Merge pull request 'Fixed payment information form in address recipient book and fixed some headers' (#163) from SEND016 into main

Reviewed-on: #163
Reviewed-by: tech <tech.sendico@proton.me>

.gitignore

@@ -9,4 +9,5 @@ untranslated.txt
 generate_protos.sh
 update_dep.sh
 .vscode/
-.gocache/
+.gocache/
+.cache/

api/billing/fees/go.mod

@@ -11,7 +11,7 @@ require (
 	github.com/tech/sendico/pkg v0.1.0
 	go.mongodb.org/mongo-driver v1.17.6
 	go.uber.org/zap v1.27.1
-	google.golang.org/grpc v1.77.0
+	google.golang.org/grpc v1.78.0
 	gopkg.in/yaml.v3 v3.0.1
 )
 
@@ -31,7 +31,7 @@ require (
 	github.com/mitchellh/mapstructure v1.5.0 // indirect
 	github.com/montanaflynn/stats v0.7.1 // indirect
 	github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 // indirect
-	github.com/nats-io/nats.go v1.47.0 // indirect
+	github.com/nats-io/nats.go v1.48.0 // indirect
 	github.com/nats-io/nkeys v0.4.12 // indirect
 	github.com/nats-io/nuid v1.0.1 // indirect
 	github.com/prometheus/client_golang v1.23.2
@@ -49,6 +49,6 @@ require (
 	golang.org/x/sync v0.19.0 // indirect
 	golang.org/x/sys v0.39.0 // indirect
 	golang.org/x/text v0.32.0 // indirect
-	google.golang.org/genproto/googleapis/rpc v0.0.0-20251202230838-ff82c1b0f217 // indirect
-	google.golang.org/protobuf v1.36.10
+	google.golang.org/genproto/googleapis/rpc v0.0.0-20251222181119-0a764e51fe1b // indirect
+	google.golang.org/protobuf v1.36.11
 )

api/billing/fees/go.sum

@@ -95,8 +95,8 @@ github.com/morikuni/aec v1.0.0 h1:nP9CBfwrvYnBRgY6qfDQkygYDmYwOilePFkwzv4dU8A=
 github.com/morikuni/aec v1.0.0/go.mod h1:BbKIizmSmc5MMPqRYbxO4ZU0S0+P200+tUnFx7PXmsc=
 github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 h1:C3w9PqII01/Oq1c1nUAm88MOHcQC9l5mIlSMApZMrHA=
 github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822/go.mod h1:+n7T8mK8HuQTcFwEeznm/DIxMOiR9yIdICNftLE1DvQ=
-github.com/nats-io/nats.go v1.47.0 h1:YQdADw6J/UfGUd2Oy6tn4Hq6YHxCaJrVKayxxFqYrgM=
-github.com/nats-io/nats.go v1.47.0/go.mod h1:iRWIPokVIFbVijxuMQq4y9ttaBTMe0SFdlZfMDd+33g=
+github.com/nats-io/nats.go v1.48.0 h1:pSFyXApG+yWU/TgbKCjmm5K4wrHu86231/w84qRVR+U=
+github.com/nats-io/nats.go v1.48.0/go.mod h1:iRWIPokVIFbVijxuMQq4y9ttaBTMe0SFdlZfMDd+33g=
 github.com/nats-io/nkeys v0.4.12 h1:nssm7JKOG9/x4J8II47VWCL1Ds29avyiQDRn0ckMvDc=
 github.com/nats-io/nkeys v0.4.12/go.mod h1:MT59A1HYcjIcyQDJStTfaOY6vhy9XTUjOFo+SVsvpBg=
 github.com/nats-io/nuid v1.0.1 h1:5iA8DT8V7q8WK2EScv2padNa/rTESc1KdnPw4TC2paw=
@@ -212,12 +212,12 @@ golang.org/x/tools v0.1.12/go.mod h1:hNGJHUnrk76NpqgfD5Aqm5Crs+Hm0VOH/i9J2+nxYbc
 golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 gonum.org/v1/gonum v0.16.0 h1:5+ul4Swaf3ESvrOnidPp4GZbzf0mxVQpDCYUQE7OJfk=
 gonum.org/v1/gonum v0.16.0/go.mod h1:fef3am4MQ93R2HHpKnLk4/Tbh/s0+wqD5nfa6Pnwy4E=
-google.golang.org/genproto/googleapis/rpc v0.0.0-20251202230838-ff82c1b0f217 h1:gRkg/vSppuSQoDjxyiGfN4Upv/h/DQmIR10ZU8dh4Ww=
-google.golang.org/genproto/googleapis/rpc v0.0.0-20251202230838-ff82c1b0f217/go.mod h1:7i2o+ce6H/6BluujYR+kqX3GKH+dChPTQU19wjRPiGk=
-google.golang.org/grpc v1.77.0 h1:wVVY6/8cGA6vvffn+wWK5ToddbgdU3d8MNENr4evgXM=
-google.golang.org/grpc v1.77.0/go.mod h1:z0BY1iVj0q8E1uSQCjL9cppRj+gnZjzDnzV0dHhrNig=
-google.golang.org/protobuf v1.36.10 h1:AYd7cD/uASjIL6Q9LiTjz8JLcrh/88q5UObnmY3aOOE=
-google.golang.org/protobuf v1.36.10/go.mod h1:HTf+CrKn2C3g5S8VImy6tdcUvCska2kB7j23XfzDpco=
+google.golang.org/genproto/googleapis/rpc v0.0.0-20251222181119-0a764e51fe1b h1:Mv8VFug0MP9e5vUxfBcE3vUkV6CImK3cMNMIDFjmzxU=
+google.golang.org/genproto/googleapis/rpc v0.0.0-20251222181119-0a764e51fe1b/go.mod h1:j9x/tPzZkyxcgEFkiKEEGxfvyumM01BEtsW8xzOahRQ=
+google.golang.org/grpc v1.78.0 h1:K1XZG/yGDJnzMdd/uZHAkVqJE+xIDOcmdSFZkBUicNc=
+google.golang.org/grpc v1.78.0/go.mod h1:I47qjTo4OKbMkjA/aOOwxDIiPSBofUtQUI5EfpWvW7U=
+google.golang.org/protobuf v1.36.11 h1:fV6ZwhNocDyBLK0dj+fg8ektcVegBBuEolpbTQyBNVE=
+google.golang.org/protobuf v1.36.11/go.mod h1:HTf+CrKn2C3g5S8VImy6tdcUvCska2kB7j23XfzDpco=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c h1:Hei/4ADfdWqJk1ZMxUNpqntNwaWcugrBjAiHlqqRiVk=
 gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c/go.mod h1:JHkPIbrfpd72SG/EVd6muEfDQjcINNoR0C8j2r3qZ4Q=

api/billing/fees/internal/service/fees/internal/calculator/impl.go

@@ -90,10 +90,6 @@ func (c *quoteCalculator) Compute(ctx context.Context, plan *model.FeePlan, inte
 		}
 
 		ledgerAccountRef := strings.TrimSpace(rule.LedgerAccountRef)
-		if ledgerAccountRef == "" {
-			c.logger.Warn("fee rule missing ledger account reference", zap.String("rule_id", rule.RuleID))
-			continue
-		}
 
 		amount, scale, calcErr := c.calculateRuleAmount(baseAmount, baseScale, rule)
 		if calcErr != nil {
@@ -113,7 +109,8 @@ func (c *quoteCalculator) Compute(ctx context.Context, plan *model.FeePlan, inte
 
 		entrySide := mapEntrySide(rule.EntrySide)
 		if entrySide == accountingv1.EntrySide_ENTRY_SIDE_UNSPECIFIED {
-			entrySide = accountingv1.EntrySide_ENTRY_SIDE_CREDIT
+			// Default fees to debit (i.e. charge the customer) when entry side is not specified.
+			entrySide = accountingv1.EntrySide_ENTRY_SIDE_DEBIT
 		}
 
 		meta := map[string]string{

api/billing/fees/internal/service/fees/internal/resolver/impl.go

@@ -38,23 +38,23 @@ func New(plans storage.PlansStore, logger *zap.Logger) *feeResolver {
 	}
 }
 
-func (r *feeResolver) ResolveFeeRule(ctx context.Context, orgID *primitive.ObjectID, trigger model.Trigger, at time.Time, attrs map[string]string) (*model.FeePlan, *model.FeeRule, error) {
+func (r *feeResolver) ResolveFeeRule(ctx context.Context, orgRef *primitive.ObjectID, trigger model.Trigger, at time.Time, attrs map[string]string) (*model.FeePlan, *model.FeeRule, error) {
 	if r.plans == nil {
 		return nil, nil, merrors.InvalidArgument("fees: plans store is required")
 	}
 
 	// Try org-specific first if provided.
-	if orgID != nil && !orgID.IsZero() {
-		if plan, err := r.getOrgPlan(ctx, *orgID, at); err == nil {
+	if orgRef != nil && !orgRef.IsZero() {
+		if plan, err := r.getOrgPlan(ctx, *orgRef, at); err == nil {
 			if rule, selErr := selectRule(plan, trigger, at, attrs); selErr == nil {
 				return plan, rule, nil
 			} else if !errors.Is(selErr, ErrNoFeeRuleFound) {
-				r.logger.Warn("failed selecting rule for org plan", zap.Error(selErr), zap.String("org_ref", orgID.Hex()))
+				r.logger.Warn("failed selecting rule for org plan", zap.Error(selErr), zap.String("org_ref", orgRef.Hex()))
 				return nil, nil, selErr
 			}
-			r.logger.Debug("no matching rule in org plan; falling back to global", zap.String("org_ref", orgID.Hex()))
+			r.logger.Debug("no matching rule in org plan; falling back to global", zap.String("org_ref", orgRef.Hex()))
 		} else if !errors.Is(err, storage.ErrFeePlanNotFound) {
-			r.logger.Warn("failed resolving org fee plan", zap.Error(err), zap.String("org_ref", orgID.Hex()))
+			r.logger.Warn("failed resolving org fee plan", zap.Error(err), zap.String("org_ref", orgRef.Hex()))
 			return nil, nil, err
 		}
 	}

api/billing/fees/internal/service/fees/internal/resolver/resolver_test.go

@@ -32,8 +32,8 @@ func TestResolver_GlobalFallbackWhenOrgMissing(t *testing.T) {
 	if err != nil {
 		t.Fatalf("expected fallback to global, got error: %v", err)
 	}
-	if !plan.GetOrganizationRef().IsZero() {
-		t.Fatalf("expected global plan, got orgRef %s", plan.GetOrganizationRef().Hex())
+	if plan.OrganizationRef != nil && !plan.OrganizationRef.IsZero() {
+		t.Fatalf("expected global plan, got orgRef %s", plan.OrganizationRef.Hex())
 	}
 	if rule.RuleID != "global_capture" {
 		t.Fatalf("unexpected rule selected: %s", rule.RuleID)
@@ -59,8 +59,7 @@ func TestResolver_OrgOverridesGlobal(t *testing.T) {
 			{RuleID: "org_capture", Trigger: model.TriggerCapture, Priority: 10, Percentage: "0.03", EffectiveFrom: now.Add(-time.Hour)},
 		},
 	}
-	orgPlan.SetOrganizationRef(org)
-
+	orgPlan.OrganizationRef = &org
 	store := &memoryPlansStore{plans: []*model.FeePlan{globalPlan, orgPlan}}
 	resolver := New(store, zap.NewNop())
 
@@ -95,7 +94,7 @@ func TestResolver_SelectsHighestPriority(t *testing.T) {
 			{RuleID: "high", Trigger: model.TriggerCapture, Priority: 200, Percentage: "0.03", EffectiveFrom: now.Add(-time.Hour)},
 		},
 	}
-	plan.SetOrganizationRef(org)
+	plan.OrganizationRef = &org
 
 	store := &memoryPlansStore{plans: []*model.FeePlan{plan}}
 	resolver := New(store, zap.NewNop())
@@ -136,7 +135,7 @@ func TestResolver_EffectiveDateFiltering(t *testing.T) {
 			{RuleID: "expired", Trigger: model.TriggerCapture, Priority: 100, Percentage: "0.05", EffectiveFrom: past, EffectiveTo: &past},
 		},
 	}
-	orgPlan.SetOrganizationRef(org)
+	orgPlan.OrganizationRef = &org
 
 	globalPlan := &model.FeePlan{
 		Active:        true,
@@ -221,7 +220,7 @@ func TestResolver_MultipleActivePlansConflict(t *testing.T) {
 			{RuleID: "r1", Trigger: model.TriggerCapture, Priority: 10, Percentage: "0.05", EffectiveFrom: now.Add(-time.Hour)},
 		},
 	}
-	p1.SetOrganizationRef(org)
+	p1.OrganizationRef = &org
 	p2 := &model.FeePlan{
 		Active:        true,
 		EffectiveFrom: now.Add(-30 * time.Minute),
@@ -229,7 +228,7 @@ func TestResolver_MultipleActivePlansConflict(t *testing.T) {
 			{RuleID: "r2", Trigger: model.TriggerCapture, Priority: 20, Percentage: "0.03", EffectiveFrom: now.Add(-time.Hour)},
 		},
 	}
-	p2.SetOrganizationRef(org)
+	p2.OrganizationRef = &org
 
 	store := &memoryPlansStore{plans: []*model.FeePlan{p1, p2}}
 	resolver := New(store, zap.NewNop())
@@ -263,7 +262,7 @@ func (m *memoryPlansStore) GetActivePlan(ctx context.Context, orgRef primitive.O
 func (m *memoryPlansStore) FindActiveOrgPlan(_ context.Context, orgRef primitive.ObjectID, at time.Time) (*model.FeePlan, error) {
 	var matches []*model.FeePlan
 	for _, plan := range m.plans {
-		if plan == nil || plan.GetOrganizationRef() != orgRef {
+		if plan == nil || plan.OrganizationRef == nil || plan.OrganizationRef.IsZero() || (*plan.OrganizationRef != orgRef) {
 			continue
 		}
 		if !plan.Active {
@@ -289,7 +288,7 @@ func (m *memoryPlansStore) FindActiveOrgPlan(_ context.Context, orgRef primitive
 func (m *memoryPlansStore) FindActiveGlobalPlan(_ context.Context, at time.Time) (*model.FeePlan, error) {
 	var matches []*model.FeePlan
 	for _, plan := range m.plans {
-		if plan == nil || !plan.GetOrganizationRef().IsZero() {
+		if plan == nil || ((plan.OrganizationRef != nil) && !plan.OrganizationRef.IsZero()) {
 			continue
 		}
 		if !plan.Active {

api/billing/fees/internal/service/fees/logging.go

@@ -0,0 +1,88 @@
+package fees
+
+import (
+	"strings"
+	"time"
+
+	feesv1 "github.com/tech/sendico/pkg/proto/billing/fees/v1"
+	tracev1 "github.com/tech/sendico/pkg/proto/common/trace/v1"
+	"go.uber.org/zap"
+)
+
+func requestLogFields(meta *feesv1.RequestMeta, intent *feesv1.Intent) []zap.Field {
+	fields := logFieldsFromRequestMeta(meta)
+	fields = append(fields, logFieldsFromIntent(intent)...)
+	return fields
+}
+
+func logFieldsFromRequestMeta(meta *feesv1.RequestMeta) []zap.Field {
+	if meta == nil {
+		return nil
+	}
+	fields := make([]zap.Field, 0, 4)
+	if org := strings.TrimSpace(meta.GetOrganizationRef()); org != "" {
+		fields = append(fields, zap.String("organization_ref", org))
+	}
+	fields = append(fields, logFieldsFromTrace(meta.GetTrace())...)
+	return fields
+}
+
+func logFieldsFromIntent(intent *feesv1.Intent) []zap.Field {
+	if intent == nil {
+		return nil
+	}
+	fields := make([]zap.Field, 0, 5)
+	if trigger := intent.GetTrigger(); trigger != feesv1.Trigger_TRIGGER_UNSPECIFIED {
+		fields = append(fields, zap.String("trigger", trigger.String()))
+	}
+	if base := intent.GetBaseAmount(); base != nil {
+		if amount := strings.TrimSpace(base.GetAmount()); amount != "" {
+			fields = append(fields, zap.String("base_amount", amount))
+		}
+		if currency := strings.TrimSpace(base.GetCurrency()); currency != "" {
+			fields = append(fields, zap.String("base_currency", currency))
+		}
+	}
+	if booked := intent.GetBookedAt(); booked != nil && booked.IsValid() {
+		fields = append(fields, zap.Time("booked_at", booked.AsTime()))
+	}
+	if attrs := intent.GetAttributes(); len(attrs) > 0 {
+		fields = append(fields, zap.Int("attributes_count", len(attrs)))
+	}
+	return fields
+}
+
+func logFieldsFromTrace(trace *tracev1.TraceContext) []zap.Field {
+	if trace == nil {
+		return nil
+	}
+	fields := make([]zap.Field, 0, 3)
+	if reqRef := strings.TrimSpace(trace.GetRequestRef()); reqRef != "" {
+		fields = append(fields, zap.String("request_ref", reqRef))
+	}
+	if idem := strings.TrimSpace(trace.GetIdempotencyKey()); idem != "" {
+		fields = append(fields, zap.String("idempotency_key", idem))
+	}
+	if traceRef := strings.TrimSpace(trace.GetTraceRef()); traceRef != "" {
+		fields = append(fields, zap.String("trace_ref", traceRef))
+	}
+	return fields
+}
+
+func logFieldsFromTokenPayload(payload *feeQuoteTokenPayload) []zap.Field {
+	if payload == nil {
+		return nil
+	}
+	fields := make([]zap.Field, 0, 6)
+	if org := strings.TrimSpace(payload.OrganizationRef); org != "" {
+		fields = append(fields, zap.String("organization_ref", org))
+	}
+	if payload.ExpiresAtUnixMs > 0 {
+		fields = append(fields,
+			zap.Int64("expires_at_unix_ms", payload.ExpiresAtUnixMs),
+			zap.Time("expires_at", time.UnixMilli(payload.ExpiresAtUnixMs)))
+	}
+	fields = append(fields, logFieldsFromIntent(payload.Intent)...)
+	fields = append(fields, logFieldsFromTrace(payload.Trace)...)
+	return fields
+}

api/billing/fees/internal/service/fees/service.go

@@ -72,26 +72,57 @@ func (s *Service) Register(router routers.GRPC) error {
 }
 
 func (s *Service) QuoteFees(ctx context.Context, req *feesv1.QuoteFeesRequest) (resp *feesv1.QuoteFeesResponse, err error) {
+	var (
+		meta   *feesv1.RequestMeta
+		intent *feesv1.Intent
+	)
+	if req != nil {
+		meta = req.GetMeta()
+		intent = req.GetIntent()
+	}
+	logger := s.logger.With(requestLogFields(meta, intent)...)
+
 	start := s.clock.Now()
 	trigger := feesv1.Trigger_TRIGGER_UNSPECIFIED
-	if req != nil && req.GetIntent() != nil {
-		trigger = req.GetIntent().GetTrigger()
+	if intent != nil {
+		trigger = intent.GetTrigger()
 	}
 	var fxUsed bool
 	defer func() {
 		statusLabel := statusFromError(err)
+		linesCount := 0
+		appliedCount := 0
 		if err == nil && resp != nil {
 			fxUsed = resp.GetFxUsed() != nil
+			linesCount = len(resp.GetLines())
+			appliedCount = len(resp.GetApplied())
 		}
 		observeMetrics("quote", trigger, statusLabel, fxUsed, time.Since(start))
+
+		logFields := []zap.Field{
+			zap.String("status", statusLabel),
+			zap.Duration("duration", time.Since(start)),
+			zap.Bool("fx_used", fxUsed),
+			zap.String("trigger", trigger.String()),
+			zap.Int("lines", linesCount),
+			zap.Int("applied_rules", appliedCount),
+		}
+		if err != nil {
+			logger.Warn("QuoteFees finished", append(logFields, zap.Error(err))...)
+			return
+		}
+		logger.Info("QuoteFees finished", logFields...)
 	}()
 
+	logger.Debug("QuoteFees request received")
+
 	if err = s.validateQuoteRequest(req); err != nil {
 		return nil, err
 	}
 
 	orgRef, parseErr := primitive.ObjectIDFromHex(req.GetMeta().GetOrganizationRef())
 	if parseErr != nil {
+		logger.Warn("QuoteFees invalid organization_ref", zap.Error(parseErr))
 		err = status.Error(codes.InvalidArgument, "invalid organization_ref")
 		return nil, err
 	}
@@ -112,20 +143,59 @@ func (s *Service) QuoteFees(ctx context.Context, req *feesv1.QuoteFeesRequest) (
 }
 
 func (s *Service) PrecomputeFees(ctx context.Context, req *feesv1.PrecomputeFeesRequest) (resp *feesv1.PrecomputeFeesResponse, err error) {
+	var (
+		meta   *feesv1.RequestMeta
+		intent *feesv1.Intent
+	)
+	if req != nil {
+		meta = req.GetMeta()
+		intent = req.GetIntent()
+	}
+	logger := s.logger.With(requestLogFields(meta, intent)...)
+
 	start := s.clock.Now()
 	trigger := feesv1.Trigger_TRIGGER_UNSPECIFIED
-	if req != nil && req.GetIntent() != nil {
-		trigger = req.GetIntent().GetTrigger()
+	if intent != nil {
+		trigger = intent.GetTrigger()
 	}
-	var fxUsed bool
+	var (
+		fxUsed    bool
+		expiresAt time.Time
+	)
 	defer func() {
 		statusLabel := statusFromError(err)
+		linesCount := 0
+		appliedCount := 0
 		if err == nil && resp != nil {
 			fxUsed = resp.GetFxUsed() != nil
+			linesCount = len(resp.GetLines())
+			appliedCount = len(resp.GetApplied())
+			if ts := resp.GetExpiresAt(); ts != nil {
+				expiresAt = ts.AsTime()
+			}
 		}
 		observeMetrics("precompute", trigger, statusLabel, fxUsed, time.Since(start))
+
+		logFields := []zap.Field{
+			zap.String("status", statusLabel),
+			zap.Duration("duration", time.Since(start)),
+			zap.Bool("fx_used", fxUsed),
+			zap.String("trigger", trigger.String()),
+			zap.Int("lines", linesCount),
+			zap.Int("applied_rules", appliedCount),
+		}
+		if !expiresAt.IsZero() {
+			logFields = append(logFields, zap.Time("expires_at", expiresAt))
+		}
+		if err != nil {
+			logger.Warn("PrecomputeFees finished", append(logFields, zap.Error(err))...)
+			return
+		}
+		logger.Info("PrecomputeFees finished", logFields...)
 	}()
 
+	logger.Debug("PrecomputeFees request received")
+
 	if err = s.validatePrecomputeRequest(req); err != nil {
 		return nil, err
 	}
@@ -134,6 +204,7 @@ func (s *Service) PrecomputeFees(ctx context.Context, req *feesv1.PrecomputeFees
 
 	orgRef, parseErr := primitive.ObjectIDFromHex(req.GetMeta().GetOrganizationRef())
 	if parseErr != nil {
+		logger.Warn("PrecomputeFees invalid organization_ref", zap.Error(parseErr))
 		err = status.Error(codes.InvalidArgument, "invalid organization_ref")
 		return nil, err
 	}
@@ -148,7 +219,7 @@ func (s *Service) PrecomputeFees(ctx context.Context, req *feesv1.PrecomputeFees
 	if ttl <= 0 {
 		ttl = 60000
 	}
-	expiresAt := now.Add(time.Duration(ttl) * time.Millisecond)
+	expiresAt = now.Add(time.Duration(ttl) * time.Millisecond)
 
 	payload := feeQuoteTokenPayload{
 		OrganizationRef: req.GetMeta().GetOrganizationRef(),
@@ -159,7 +230,7 @@ func (s *Service) PrecomputeFees(ctx context.Context, req *feesv1.PrecomputeFees
 
 	var token string
 	if token, err = encodeTokenPayload(payload); err != nil {
-		s.logger.Warn("failed to encode fee quote token", zap.Error(err))
+		logger.Warn("failed to encode fee quote token", zap.Error(err))
 		err = status.Error(codes.Internal, "failed to encode fee quote token")
 		return nil, err
 	}
@@ -176,9 +247,18 @@ func (s *Service) PrecomputeFees(ctx context.Context, req *feesv1.PrecomputeFees
 }
 
 func (s *Service) ValidateFeeToken(ctx context.Context, req *feesv1.ValidateFeeTokenRequest) (resp *feesv1.ValidateFeeTokenResponse, err error) {
+	tokenLen := 0
+	if req != nil {
+		tokenLen = len(strings.TrimSpace(req.GetFeeQuoteToken()))
+	}
+	logger := s.logger.With(zap.Int("token_length", tokenLen))
+
 	start := s.clock.Now()
 	trigger := feesv1.Trigger_TRIGGER_UNSPECIFIED
-	var fxUsed bool
+	var (
+		fxUsed       bool
+		resultReason string
+	)
 	defer func() {
 		statusLabel := statusFromError(err)
 		if err == nil && resp != nil {
@@ -191,9 +271,28 @@ func (s *Service) ValidateFeeToken(ctx context.Context, req *feesv1.ValidateFeeT
 			}
 		}
 		observeMetrics("validate", trigger, statusLabel, fxUsed, time.Since(start))
+
+		logFields := []zap.Field{
+			zap.String("status", statusLabel),
+			zap.Duration("duration", time.Since(start)),
+			zap.Bool("fx_used", fxUsed),
+			zap.String("trigger", trigger.String()),
+			zap.Bool("valid", resp != nil && resp.GetValid()),
+		}
+		if resultReason != "" {
+			logFields = append(logFields, zap.String("reason", resultReason))
+		}
+		if err != nil {
+			logger.Warn("ValidateFeeToken finished", append(logFields, zap.Error(err))...)
+			return
+		}
+		logger.Info("ValidateFeeToken finished", logFields...)
 	}()
 
+	logger.Debug("ValidateFeeToken request received")
+
 	if req == nil || strings.TrimSpace(req.GetFeeQuoteToken()) == "" {
+		resultReason = "missing_token"
 		err = status.Error(codes.InvalidArgument, "fee_quote_token is required")
 		return nil, err
 	}
@@ -202,21 +301,29 @@ func (s *Service) ValidateFeeToken(ctx context.Context, req *feesv1.ValidateFeeT
 
 	payload, decodeErr := decodeTokenPayload(req.GetFeeQuoteToken())
 	if decodeErr != nil {
-		s.logger.Warn("failed to decode fee quote token", zap.Error(decodeErr))
+		resultReason = "invalid_token"
+		logger.Warn("failed to decode fee quote token", zap.Error(decodeErr))
 		resp = &feesv1.ValidateFeeTokenResponse{Meta: &feesv1.ResponseMeta{}, Valid: false, Reason: "invalid_token"}
 		return resp, nil
 	}
 
-	trigger = payload.Intent.GetTrigger()
+	logger = logger.With(logFieldsFromTokenPayload(&payload)...)
+
+	if payload.Intent != nil {
+		trigger = payload.Intent.GetTrigger()
+	}
 
 	if now.UnixMilli() > payload.ExpiresAtUnixMs {
+		resultReason = "expired"
+		logger.Info("fee quote token expired")
 		resp = &feesv1.ValidateFeeTokenResponse{Meta: &feesv1.ResponseMeta{}, Valid: false, Reason: "expired"}
 		return resp, nil
 	}
 
 	orgRef, parseErr := primitive.ObjectIDFromHex(payload.OrganizationRef)
 	if parseErr != nil {
-		s.logger.Warn("token contained invalid organization reference", zap.Error(parseErr))
+		resultReason = "invalid_token"
+		logger.Warn("token contained invalid organization reference", zap.Error(parseErr))
 		resp = &feesv1.ValidateFeeTokenResponse{Meta: &feesv1.ResponseMeta{}, Valid: false, Reason: "invalid_token"}
 		return resp, nil
 	}
@@ -280,6 +387,16 @@ func (s *Service) computeQuoteWithTime(ctx context.Context, orgRef primitive.Obj
 		bookedAt = intent.GetBookedAt().AsTime()
 	}
 
+	logFields := []zap.Field{
+		zap.Time("booked_at_used", bookedAt),
+	}
+	if !orgRef.IsZero() {
+		logFields = append(logFields, zap.String("organization_ref", orgRef.Hex()))
+	}
+	logFields = append(logFields, logFieldsFromIntent(intent)...)
+	logFields = append(logFields, logFieldsFromTrace(trace)...)
+	logger := s.logger.With(logFields...)
+
 	var orgPtr *primitive.ObjectID
 	if !orgRef.IsZero() {
 		orgPtr = &orgRef
@@ -288,7 +405,7 @@ func (s *Service) computeQuoteWithTime(ctx context.Context, orgRef primitive.Obj
 	plan, rule, err := s.resolver.ResolveFeeRule(ctx, orgPtr, convertTrigger(intent.GetTrigger()), bookedAt, intent.GetAttributes())
 	if err != nil {
 		switch {
-	case errors.Is(err, merrors.ErrNoData):
+		case errors.Is(err, merrors.ErrNoData):
 			return nil, nil, nil, status.Error(codes.NotFound, "fee rule not found")
 		case errors.Is(err, merrors.ErrDataConflict):
 			return nil, nil, nil, status.Error(codes.FailedPrecondition, "conflicting fee rules")
@@ -297,7 +414,7 @@ func (s *Service) computeQuoteWithTime(ctx context.Context, orgRef primitive.Obj
 		case errors.Is(err, storage.ErrFeePlanNotFound):
 			return nil, nil, nil, status.Error(codes.NotFound, "fee plan not found")
 		default:
-			s.logger.Warn("failed to resolve fee rule", zap.Error(err))
+			logger.Warn("failed to resolve fee rule", zap.Error(err))
 			return nil, nil, nil, status.Error(codes.Internal, "failed to resolve fee rule")
 		}
 	}
@@ -313,7 +430,7 @@ func (s *Service) computeQuoteWithTime(ctx context.Context, orgRef primitive.Obj
 		if errors.Is(calcErr, merrors.ErrInvalidArg) {
 			return nil, nil, nil, status.Error(codes.InvalidArgument, calcErr.Error())
 		}
-		s.logger.Warn("failed to compute fee quote", zap.Error(calcErr))
+		logger.Warn("failed to compute fee quote", zap.Error(calcErr))
 		return nil, nil, nil, status.Error(codes.Internal, "failed to compute fee quote")
 	}
 

api/billing/fees/internal/service/fees/service_test.go

@@ -49,7 +49,7 @@ func TestQuoteFees_ComputesDerivedLines(t *testing.T) {
 		},
 	}
 	plan.SetID(primitive.NewObjectID())
-	plan.SetOrganizationRef(orgRef)
+	plan.OrganizationRef = &orgRef
 
 	service := NewService(
 		zap.NewNop(),
@@ -163,7 +163,7 @@ func TestQuoteFees_FiltersByAttributesAndDates(t *testing.T) {
 		},
 	}
 	plan.SetID(primitive.NewObjectID())
-	plan.SetOrganizationRef(orgRef)
+	plan.OrganizationRef = &orgRef
 
 	service := NewService(
 		zap.NewNop(),
@@ -224,7 +224,7 @@ func TestQuoteFees_RoundingDown(t *testing.T) {
 		},
 	}
 	plan.SetID(primitive.NewObjectID())
-	plan.SetOrganizationRef(orgRef)
+	plan.OrganizationRef = &orgRef
 
 	service := NewService(
 		zap.NewNop(),
@@ -277,7 +277,7 @@ func TestQuoteFees_UsesInjectedCalculator(t *testing.T) {
 		},
 	}
 	plan.SetID(primitive.NewObjectID())
-	plan.SetOrganizationRef(orgRef)
+	plan.OrganizationRef = &orgRef
 
 	result := &types.CalculationResult{
 		Lines: []*feesv1.DerivedPostingLine{
@@ -353,7 +353,7 @@ func TestQuoteFees_PopulatesFxUsed(t *testing.T) {
 		},
 	}
 	plan.SetID(primitive.NewObjectID())
-	plan.SetOrganizationRef(orgRef)
+	plan.OrganizationRef = &orgRef
 
 	fakeOracle := &oracleclient.Fake{
 		LatestRateFn: func(ctx context.Context, req oracleclient.LatestRateParams) (*oracleclient.RateSnapshot, error) {
@@ -452,7 +452,7 @@ func (s *stubPlansStore) FindActiveOrgPlan(_ context.Context, orgRef primitive.O
 	if s.plan == nil {
 		return nil, storage.ErrFeePlanNotFound
 	}
-	if s.plan.GetOrganizationRef() != orgRef {
+	if (s.plan.OrganizationRef != nil) && (*s.plan.OrganizationRef != orgRef) {
 		return nil, storage.ErrFeePlanNotFound
 	}
 	if !s.plan.Active {

api/billing/fees/storage/model/plan.go

@@ -5,6 +5,7 @@ import (
 
 	"github.com/tech/sendico/pkg/db/storable"
 	"github.com/tech/sendico/pkg/model"
+	"go.mongodb.org/mongo-driver/bson/primitive"
 )
 
 const (
@@ -25,14 +26,14 @@ const (
 
 // FeePlan describes a collection of fee rules for an organisation.
 type FeePlan struct {
-	storable.Base               `bson:",inline" json:",inline"`
-	model.OrganizationBoundBase `bson:",inline" json:",inline"`
-	model.Describable           `bson:",inline" json:",inline"`
-	Active                      bool              `bson:"active"             json:"active"`
-	EffectiveFrom               time.Time         `bson:"effectiveFrom"      json:"effectiveFrom"`
-	EffectiveTo                 *time.Time        `bson:"effectiveTo,omitempty" json:"effectiveTo,omitempty"`
-	Rules                       []FeeRule         `bson:"rules,omitempty"    json:"rules,omitempty"`
-	Metadata                    map[string]string `bson:"metadata,omitempty" json:"metadata,omitempty"`
+	storable.Base     `bson:",inline" json:",inline"`
+	model.Describable `bson:",inline" json:",inline"`
+	OrganizationRef   *primitive.ObjectID `bson:"organizationRef,omitempty" json:"organizationRef,omitempty"`
+	Active            bool                `bson:"active"             json:"active"`
+	EffectiveFrom     time.Time           `bson:"effectiveFrom"      json:"effectiveFrom"`
+	EffectiveTo       *time.Time          `bson:"effectiveTo,omitempty" json:"effectiveTo,omitempty"`
+	Rules             []FeeRule           `bson:"rules,omitempty"    json:"rules,omitempty"`
+	Metadata          map[string]string   `bson:"metadata,omitempty" json:"metadata,omitempty"`
 }
 
 // Collection implements storable.Storable.

api/fx/ingestor/config.yml

@@ -11,12 +11,18 @@ market:
     - driver: CBR
       settings:
         base_url: "https://www.cbr.ru"
+        user_agent: "Mozilla/5.0 (compatible; SendicoFX/1.0; +https://app.sendico.io)"
+        accept_header: "application/xml,text/xml;q=0.9,*/*;q=0.8"
   pairs:
     BINANCE:
       - base: "USDT"
         quote: "EUR"
         symbol: "EURUSDT"
         invert: true
+      - base: "USD"
+        quote: "USDT"
+        symbol: "USDTUSD"
+        invert: true
       - base: "UAH"
         quote: "USDT"
         symbol: "USDTUAH"

api/fx/ingestor/go.mod

@@ -32,7 +32,7 @@ require (
 	github.com/mitchellh/mapstructure v1.5.0 // indirect
 	github.com/montanaflynn/stats v0.7.1 // indirect
 	github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 // indirect
-	github.com/nats-io/nats.go v1.47.0 // indirect
+	github.com/nats-io/nats.go v1.48.0 // indirect
 	github.com/nats-io/nkeys v0.4.12 // indirect
 	github.com/nats-io/nuid v1.0.1 // indirect
 	github.com/prometheus/client_model v0.6.2 // indirect
@@ -49,7 +49,7 @@ require (
 	golang.org/x/sync v0.19.0 // indirect
 	golang.org/x/sys v0.39.0 // indirect
 	golang.org/x/text v0.32.0 // indirect
-	google.golang.org/genproto/googleapis/rpc v0.0.0-20251202230838-ff82c1b0f217 // indirect
-	google.golang.org/grpc v1.77.0 // indirect
-	google.golang.org/protobuf v1.36.10 // indirect
+	google.golang.org/genproto/googleapis/rpc v0.0.0-20251222181119-0a764e51fe1b // indirect
+	google.golang.org/grpc v1.78.0 // indirect
+	google.golang.org/protobuf v1.36.11 // indirect
 )

api/fx/ingestor/go.sum

@@ -95,8 +95,8 @@ github.com/morikuni/aec v1.0.0 h1:nP9CBfwrvYnBRgY6qfDQkygYDmYwOilePFkwzv4dU8A=
 github.com/morikuni/aec v1.0.0/go.mod h1:BbKIizmSmc5MMPqRYbxO4ZU0S0+P200+tUnFx7PXmsc=
 github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 h1:C3w9PqII01/Oq1c1nUAm88MOHcQC9l5mIlSMApZMrHA=
 github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822/go.mod h1:+n7T8mK8HuQTcFwEeznm/DIxMOiR9yIdICNftLE1DvQ=
-github.com/nats-io/nats.go v1.47.0 h1:YQdADw6J/UfGUd2Oy6tn4Hq6YHxCaJrVKayxxFqYrgM=
-github.com/nats-io/nats.go v1.47.0/go.mod h1:iRWIPokVIFbVijxuMQq4y9ttaBTMe0SFdlZfMDd+33g=
+github.com/nats-io/nats.go v1.48.0 h1:pSFyXApG+yWU/TgbKCjmm5K4wrHu86231/w84qRVR+U=
+github.com/nats-io/nats.go v1.48.0/go.mod h1:iRWIPokVIFbVijxuMQq4y9ttaBTMe0SFdlZfMDd+33g=
 github.com/nats-io/nkeys v0.4.12 h1:nssm7JKOG9/x4J8II47VWCL1Ds29avyiQDRn0ckMvDc=
 github.com/nats-io/nkeys v0.4.12/go.mod h1:MT59A1HYcjIcyQDJStTfaOY6vhy9XTUjOFo+SVsvpBg=
 github.com/nats-io/nuid v1.0.1 h1:5iA8DT8V7q8WK2EScv2padNa/rTESc1KdnPw4TC2paw=
@@ -212,12 +212,12 @@ golang.org/x/tools v0.1.12/go.mod h1:hNGJHUnrk76NpqgfD5Aqm5Crs+Hm0VOH/i9J2+nxYbc
 golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 gonum.org/v1/gonum v0.16.0 h1:5+ul4Swaf3ESvrOnidPp4GZbzf0mxVQpDCYUQE7OJfk=
 gonum.org/v1/gonum v0.16.0/go.mod h1:fef3am4MQ93R2HHpKnLk4/Tbh/s0+wqD5nfa6Pnwy4E=
-google.golang.org/genproto/googleapis/rpc v0.0.0-20251202230838-ff82c1b0f217 h1:gRkg/vSppuSQoDjxyiGfN4Upv/h/DQmIR10ZU8dh4Ww=
-google.golang.org/genproto/googleapis/rpc v0.0.0-20251202230838-ff82c1b0f217/go.mod h1:7i2o+ce6H/6BluujYR+kqX3GKH+dChPTQU19wjRPiGk=
-google.golang.org/grpc v1.77.0 h1:wVVY6/8cGA6vvffn+wWK5ToddbgdU3d8MNENr4evgXM=
-google.golang.org/grpc v1.77.0/go.mod h1:z0BY1iVj0q8E1uSQCjL9cppRj+gnZjzDnzV0dHhrNig=
-google.golang.org/protobuf v1.36.10 h1:AYd7cD/uASjIL6Q9LiTjz8JLcrh/88q5UObnmY3aOOE=
-google.golang.org/protobuf v1.36.10/go.mod h1:HTf+CrKn2C3g5S8VImy6tdcUvCska2kB7j23XfzDpco=
+google.golang.org/genproto/googleapis/rpc v0.0.0-20251222181119-0a764e51fe1b h1:Mv8VFug0MP9e5vUxfBcE3vUkV6CImK3cMNMIDFjmzxU=
+google.golang.org/genproto/googleapis/rpc v0.0.0-20251222181119-0a764e51fe1b/go.mod h1:j9x/tPzZkyxcgEFkiKEEGxfvyumM01BEtsW8xzOahRQ=
+google.golang.org/grpc v1.78.0 h1:K1XZG/yGDJnzMdd/uZHAkVqJE+xIDOcmdSFZkBUicNc=
+google.golang.org/grpc v1.78.0/go.mod h1:I47qjTo4OKbMkjA/aOOwxDIiPSBofUtQUI5EfpWvW7U=
+google.golang.org/protobuf v1.36.11 h1:fV6ZwhNocDyBLK0dj+fg8ektcVegBBuEolpbTQyBNVE=
+google.golang.org/protobuf v1.36.11/go.mod h1:HTf+CrKn2C3g5S8VImy6tdcUvCska2kB7j23XfzDpco=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c h1:Hei/4ADfdWqJk1ZMxUNpqntNwaWcugrBjAiHlqqRiVk=
 gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c/go.mod h1:JHkPIbrfpd72SG/EVd6muEfDQjcINNoR0C8j2r3qZ4Q=

api/fx/ingestor/internal/ingestor/service.go

@@ -85,6 +85,7 @@ func (s *Service) executePoll(ctx context.Context) error {
 
 func (s *Service) pollOnce(ctx context.Context) error {
 	var firstErr error
+	failures := 0
 	for _, pair := range s.pairs {
 		start := time.Now()
 		err := s.upsertPair(ctx, pair)
@@ -96,14 +97,24 @@ func (s *Service) pollOnce(ctx context.Context) error {
 			if firstErr == nil {
 				firstErr = err
 			}
+			failures++
 			s.logger.Warn("Failed to ingest pair",
 				zap.String("symbol", pair.Symbol),
 				zap.String("source", pair.Source.String()),
+				zap.String("provider", pair.Provider),
+				zap.String("base", pair.Base),
+				zap.String("quote", pair.Quote),
+				zap.Bool("invert", pair.Invert),
 				zap.Duration("elapsed", elapsed),
 				zap.Error(err),
 			)
 		}
 	}
+	if failures > 0 {
+		s.logger.Warn("Ingestion poll completed with failures", zap.Int("failures", failures), zap.Int("total", len(s.pairs)))
+	} else {
+		s.logger.Info("Ingestion poll completed", zap.Int("total", len(s.pairs)))
+	}
 	return firstErr
 }
 
@@ -115,7 +126,7 @@ func (s *Service) upsertPair(ctx context.Context, pair config.Pair) error {
 
 	ticker, err := connector.FetchTicker(ctx, pair.Symbol)
 	if err != nil {
-		return merrors.InternalWrap(err, "fetch ticker")
+		return merrors.InternalWrap(err, "fetch ticker: "+pair.Symbol)
 	}
 
 	bid, err := parseDecimal(ticker.BidPrice)
@@ -172,9 +183,14 @@ func (s *Service) upsertPair(ctx context.Context, pair config.Pair) error {
 	s.logger.Debug("Snapshot ingested",
 		zap.String("pair", pair.Base+"/"+pair.Quote),
 		zap.String("provider", pair.Provider),
+		zap.String("source", pair.Source.String()),
+		zap.String("provider_ref", snapshot.ProviderRef),
 		zap.String("bid", snapshot.Bid),
 		zap.String("ask", snapshot.Ask),
 		zap.String("mid", snapshot.Mid),
+		zap.String("spread_bps", snapshot.SpreadBps),
+		zap.Int64("asof_unix_ms", snapshot.AsOfUnixMs),
+		zap.String("rate_ref", snapshot.RateRef),
 	)
 
 	return nil

api/fx/ingestor/internal/market/cbr/connector.go

@@ -23,7 +23,7 @@ import (
 type cbrConnector struct {
 	id            mmodel.Driver
 	provider      string
-	client        *http.Client
+	http          *httpClient
 	base          string
 	dailyPath     string
 	directoryPath string
@@ -60,6 +60,8 @@ func NewConnector(logger mlogger.Logger, settings model.SettingsT) (mmodel.Conne
 	directoryPath := defaultDirectoryPath
 	dailyPath := defaultDailyPath
 	dynamicPath := defaultDynamicPath
+	userAgent := defaultUserAgent
+	acceptHeader := defaultAccept
 
 	if settings != nil {
 		if value, ok := settings["base_url"].(string); ok && strings.TrimSpace(value) != "" {
@@ -77,6 +79,12 @@ func NewConnector(logger mlogger.Logger, settings model.SettingsT) (mmodel.Conne
 		if value, ok := settings["dynamic_path"].(string); ok && strings.TrimSpace(value) != "" {
 			dynamicPath = strings.TrimSpace(value)
 		}
+		if value, ok := settings["user_agent"].(string); ok && strings.TrimSpace(value) != "" {
+			userAgent = strings.TrimSpace(value)
+		}
+		if value, ok := settings["accept_header"].(string); ok && strings.TrimSpace(value) != "" {
+			acceptHeader = strings.TrimSpace(value)
+		}
 		dialTimeout = common.DurationSetting(settings, "dial_timeout_seconds", dialTimeout)
 		dialKeepAlive = common.DurationSetting(settings, "dial_keep_alive_seconds", dialKeepAlive)
 		tlsHandshakeTimeout = common.DurationSetting(settings, "tls_handshake_timeout_seconds", tlsHandshakeTimeout)
@@ -99,13 +107,24 @@ func NewConnector(logger mlogger.Logger, settings model.SettingsT) (mmodel.Conne
 		transport = customTransport
 	}
 
+	client := &http.Client{
+		Timeout:   requestTimeout,
+		Transport: transport,
+	}
+	referer := parsed.String()
+
 	connector := &cbrConnector{
 		id:       mmodel.DriverCBR,
 		provider: provider,
-		client: &http.Client{
-			Timeout:   requestTimeout,
-			Transport: transport,
-		},
+		http: newHTTPClient(
+			logger,
+			client,
+			httpClientOptions{
+				userAgent: userAgent,
+				accept:    acceptHeader,
+				referer:   referer,
+			},
+		),
 		base:          strings.TrimRight(parsed.String(), "/"),
 		dailyPath:     dailyPath,
 		directoryPath: directoryPath,
@@ -161,20 +180,32 @@ func (c *cbrConnector) refreshDirectory() error {
 		return err
 	}
 
-	req, err := http.NewRequest(http.MethodGet, endpoint, nil)
+	req, err := c.http.NewRequest(context.Background(), http.MethodGet, endpoint)
 	if err != nil {
 		return merrors.InternalWrap(err, "cbr: build directory request")
 	}
 
-	resp, err := c.client.Do(req)
+	resp, err := c.http.Do(req)
 	if err != nil {
-		c.logger.Warn("CBR directory request failed", zap.Error(err))
+		c.logger.Warn(
+			"CBR directory request failed",
+			zap.Error(err),
+			zap.String("endpoint", endpoint),
+			zap.String("referer", c.http.headerValue("Referer")),
+			zap.String("user_agent", c.http.headerValue("User-Agent")),
+		)
 		return merrors.InternalWrap(err, "cbr: directory request failed")
 	}
 	defer resp.Body.Close()
 
 	if resp.StatusCode != http.StatusOK {
-		c.logger.Warn("CBR directory returned non-OK status", zap.Int("status", resp.StatusCode))
+		c.logger.Warn(
+			"CBR directory returned non-OK status",
+			zap.Int("status", resp.StatusCode),
+			zap.String("endpoint", endpoint),
+			zap.String("referer", c.http.headerValue("Referer")),
+			zap.String("user_agent", c.http.headerValue("User-Agent")),
+		)
 		return merrors.Internal("cbr: unexpected status " + strconv.Itoa(resp.StatusCode))
 	}
 
@@ -183,12 +214,13 @@ func (c *cbrConnector) refreshDirectory() error {
 
 	var directory valuteDirectory
 	if err := decoder.Decode(&directory); err != nil {
-		c.logger.Warn("CBR directory decode failed", zap.Error(err))
+		c.logger.Warn("CBR directory decode failed", zap.Error(err), zap.String("endpoint", endpoint))
 		return merrors.InternalWrap(err, "cbr: decode directory")
 	}
 
-	mapping, err := buildValuteMapping(directory.Items)
+	mapping, err := buildValuteMapping(c.logger.Named("mapper"), directory.Items)
 	if err != nil {
+		c.logger.Warn("Failed to build currencies mapping", zap.Error(err), zap.String("endpoint", endpoint))
 		return err
 	}
 
@@ -200,23 +232,32 @@ func (c *cbrConnector) refreshDirectory() error {
 func (c *cbrConnector) fetchDailyRate(ctx context.Context, valute valuteInfo) (string, error) {
 	endpoint, err := c.buildURL(c.dailyPath, nil)
 	if err != nil {
+		c.logger.Warn("Failed to build daily fetch URL", zap.Error(err), zap.String("path", c.dailyPath))
 		return "", err
 	}
 
-	req, err := http.NewRequestWithContext(ctx, http.MethodGet, endpoint, nil)
+	req, err := c.http.NewRequest(ctx, http.MethodGet, endpoint)
 	if err != nil {
+		c.logger.Warn("Failed to request daily rate", zap.Error(err), zap.String("endpoint", endpoint))
 		return "", merrors.InternalWrap(err, "cbr: build daily request")
 	}
 
-	resp, err := c.client.Do(req)
+	resp, err := c.http.Do(req)
 	if err != nil {
-		c.logger.Warn("CBR daily request failed", zap.String("currency", valute.ISOCharCode), zap.Error(err))
+		c.logger.Warn("CBR daily request failed",
+			zap.Error(err), zap.String("currency", valute.ISOCharCode),
+			zap.String("endpoint", endpoint), zap.String("referer", c.http.headerValue("Referer")),
+			zap.String("user_agent", c.http.headerValue("User-Agent")),
+		)
 		return "", merrors.InternalWrap(err, "cbr: daily request failed")
 	}
 	defer resp.Body.Close()
 
 	if resp.StatusCode != http.StatusOK {
-		c.logger.Warn("CBR daily returned non-OK status", zap.Int("status", resp.StatusCode))
+		c.logger.Warn(
+			"CBR daily returned non-OK status", zap.Int("status", resp.StatusCode),
+			zap.String("currency", valute.ISOCharCode), zap.String("endpoint", endpoint),
+		)
 		return "", merrors.Internal("cbr: unexpected status " + strconv.Itoa(resp.StatusCode))
 	}
 
@@ -225,7 +266,9 @@ func (c *cbrConnector) fetchDailyRate(ctx context.Context, valute valuteInfo) (s
 
 	var payload dailyRates
 	if err := decoder.Decode(&payload); err != nil {
-		c.logger.Warn("CBR daily decode failed", zap.Error(err))
+		c.logger.Warn("CBR daily decode failed", zap.Error(err),
+			zap.String("currency", valute.ISOCharCode), zap.String("endpoint", endpoint),
+		)
 		return "", merrors.InternalWrap(err, "cbr: decode daily response")
 	}
 
@@ -247,25 +290,40 @@ func (c *cbrConnector) fetchHistoricalRate(ctx context.Context, valute valuteInf
 		"date_req2": date.Format("02/01/2006"),
 		"VAL_NM_RQ": valute.ID,
 	}
+	dateStr := date.Format("2006-01-02")
 	endpoint, err := c.buildURL(c.dynamicPath, query)
 	if err != nil {
 		return "", err
 	}
 
-	req, err := http.NewRequestWithContext(ctx, http.MethodGet, endpoint, nil)
+	req, err := c.http.NewRequest(ctx, http.MethodGet, endpoint)
 	if err != nil {
 		return "", merrors.InternalWrap(err, "cbr: build historical request")
 	}
 
-	resp, err := c.client.Do(req)
+	resp, err := c.http.Do(req)
 	if err != nil {
-		c.logger.Warn("CBR historical request failed", zap.String("currency", valute.ISOCharCode), zap.Error(err))
+		c.logger.Warn(
+			"CBR historical request failed",
+			zap.String("currency", valute.ISOCharCode),
+			zap.String("date", dateStr),
+			zap.String("endpoint", endpoint),
+			zap.String("referer", c.http.headerValue("Referer")),
+			zap.String("user_agent", c.http.headerValue("User-Agent")),
+			zap.Error(err),
+		)
 		return "", merrors.InternalWrap(err, "cbr: historical request failed")
 	}
 	defer resp.Body.Close()
 
 	if resp.StatusCode != http.StatusOK {
-		c.logger.Warn("CBR historical returned non-OK status", zap.Int("status", resp.StatusCode))
+		c.logger.Warn(
+			"CBR historical returned non-OK status",
+			zap.Int("status", resp.StatusCode),
+			zap.String("currency", valute.ISOCharCode),
+			zap.String("date", dateStr),
+			zap.String("endpoint", endpoint),
+		)
 		return "", merrors.Internal("cbr: unexpected status " + strconv.Itoa(resp.StatusCode))
 	}
 
@@ -274,7 +332,13 @@ func (c *cbrConnector) fetchHistoricalRate(ctx context.Context, valute valuteInf
 
 	var payload dynamicRates
 	if err := decoder.Decode(&payload); err != nil {
-		c.logger.Warn("CBR historical decode failed", zap.Error(err))
+		c.logger.Warn(
+			"CBR historical decode failed",
+			zap.String("currency", valute.ISOCharCode),
+			zap.String("date", dateStr),
+			zap.String("endpoint", endpoint),
+			zap.Error(err),
+		)
 		return "", merrors.InternalWrap(err, "cbr: decode historical response")
 	}
 
@@ -337,7 +401,7 @@ type valuteMapping struct {
 	byID  map[string]valuteInfo
 }
 
-func buildValuteMapping(items []valuteItem) (*valuteMapping, error) {
+func buildValuteMapping(logger *zap.Logger, items []valuteItem) (*valuteMapping, error) {
 	byISO := make(map[string]valuteInfo, len(items))
 	byID := make(map[string]valuteInfo, len(items))
 	byNum := make(map[string]string, len(items))
@@ -348,12 +412,19 @@ func buildValuteMapping(items []valuteItem) (*valuteMapping, error) {
 		isoNum := strings.TrimSpace(item.ISONum)
 		name := strings.TrimSpace(item.Name)
 		engName := strings.TrimSpace(item.EngName)
+
 		nominal, err := parseNominal(item.NominalStr)
 		if err != nil {
 			return nil, merrors.InvalidDataType("cbr: parse directory nominal: " + err.Error())
 		}
+
 		if id == "" || isoChar == "" {
-			return nil, merrors.InvalidDataType("cbr: directory contains entry with empty id or iso code")
+			logger.Info("Skipping invalid currency entry",
+				zap.String("id", id),
+				zap.String("iso_char", isoChar),
+				zap.String("name", name),
+			)
+			continue
 		}
 
 		info := valuteInfo{
@@ -365,12 +436,76 @@ func buildValuteMapping(items []valuteItem) (*valuteMapping, error) {
 			Nominal:     nominal,
 		}
 
-		if existing, ok := byISO[isoChar]; ok && existing.ID != id {
-			return nil, merrors.InvalidDataType("cbr: duplicate ISO code " + isoChar)
+		// Handle duplicate ISO char codes (e.g. DEM with different IDs / nominals).
+		if existing, ok := byISO[isoChar]; ok {
+			// Same ISO + same ID: duplicate entry, just ignore.
+			if existing.ID == id {
+				logger.Debug("Duplicate directory entry for same ISO and ID, ignoring",
+					zap.String("iso_code", isoChar),
+					zap.String("id", id),
+				)
+				continue
+			}
+
+			// Different IDs but same ISO char.
+			// Choose canonical entry:
+			//  1) Prefer nominal == 1
+			//  2) Otherwise prefer smaller nominal
+			keepExisting := true
+
+			if existing.Nominal != 1 && info.Nominal == 1 {
+				keepExisting = false
+			} else if existing.Nominal == 1 && info.Nominal != 1 {
+				keepExisting = true
+			} else if info.Nominal < existing.Nominal {
+				keepExisting = false
+			}
+
+			if keepExisting {
+				logger.Warn("Ignoring duplicate ISO currency entry with less preferred nominal",
+					zap.String("iso_code", isoChar),
+					zap.String("existing_id", existing.ID),
+					zap.Int64("existing_nominal", existing.Nominal),
+					zap.String("new_id", info.ID),
+					zap.Int64("new_nominal", info.Nominal),
+				)
+				// We keep the old one, just skip the new.
+				continue
+			}
+
+			// Replace existing mapping with the new, more canonical one.
+			logger.Warn("Replacing currency mapping due to more canonical nominal",
+				zap.String("iso_code", isoChar),
+				zap.String("old_id", existing.ID),
+				zap.Int64("old_nominal", existing.Nominal),
+				zap.String("new_id", info.ID),
+				zap.Int64("new_nominal", info.Nominal),
+			)
+
+			// Update byID: drop old ID, add new one
+			delete(byID, existing.ID)
+			byID[id] = info
+
+			// Update ISO mapping
+			byISO[isoChar] = info
+
+			// Update numeric-code index if present
+			if isoNum != "" {
+				if existingID, ok := byNum[isoNum]; ok && existingID != id {
+					return nil, merrors.InvalidDataType("cbr: duplicate ISO numeric code " + isoNum)
+				}
+				byNum[isoNum] = id
+			}
+
+			continue
 		}
+
+		// No existing ISO entry, do normal uniqueness checks.
+
 		if existing, ok := byID[id]; ok && existing.ISOCharCode != isoChar {
 			return nil, merrors.InvalidDataType("cbr: duplicate valute id " + id)
 		}
+
 		if isoNum != "" {
 			if existingID, ok := byNum[isoNum]; ok && existingID != id {
 				return nil, merrors.InvalidDataType("cbr: duplicate ISO numeric code " + isoNum)
@@ -378,6 +513,8 @@ func buildValuteMapping(items []valuteItem) (*valuteMapping, error) {
 			byNum[isoNum] = id
 		}
 
+		logger.Info("Installing currency code", zap.String("iso_code", isoChar), zap.String("id", id), zap.Int64("nominal", nominal))
+
 		byISO[isoChar] = info
 		byID[id] = info
 	}

api/fx/ingestor/internal/market/cbr/http_client.go

@@ -0,0 +1,85 @@
+package cbr
+
+import (
+	"context"
+	"net/http"
+	"strings"
+
+	"go.uber.org/zap"
+)
+
+const (
+	defaultUserAgent = "Mozilla/5.0 (compatible; SendicoFX/1.0; +https://app.sendico.io)"
+	defaultAccept    = "application/xml,text/xml;q=0.9,*/*;q=0.8"
+)
+
+// httpClient wraps http.Client to ensure CBR requests always carry required headers.
+type httpClient struct {
+	client  *http.Client
+	headers http.Header
+	logger  *zap.Logger
+}
+
+type httpClientOptions struct {
+	userAgent string
+	accept    string
+	referer   string
+}
+
+func newHTTPClient(logger *zap.Logger, client *http.Client, opts httpClientOptions) *httpClient {
+	userAgent := opts.userAgent
+	if strings.TrimSpace(userAgent) == "" {
+		userAgent = defaultUserAgent
+	}
+
+	accept := opts.accept
+	if strings.TrimSpace(accept) == "" {
+		accept = defaultAccept
+	}
+
+	referer := opts.referer
+	if strings.TrimSpace(referer) == "" {
+		referer = defaultCBRBaseURL
+	}
+	l := logger.Named("http_client")
+
+	headers := make(http.Header, 3)
+	headers.Set("User-Agent", userAgent)
+	headers.Set("Accept", accept)
+	headers.Set("Referer", referer)
+
+	l.Info("HTTP client initialized", zap.String("user_agent", userAgent),
+		zap.String("accept", accept), zap.String("referrer", referer))
+
+	return &httpClient{
+		client:  client,
+		headers: headers,
+		logger:  l,
+	}
+}
+
+func (h *httpClient) NewRequest(ctx context.Context, method, endpoint string) (*http.Request, error) {
+	return http.NewRequestWithContext(ctx, method, endpoint, nil)
+}
+
+func (h *httpClient) Do(req *http.Request) (*http.Response, error) {
+	enriched := req.Clone(req.Context())
+	for key, values := range h.headers {
+		if enriched.Header.Get(key) != "" {
+			continue
+		}
+		for _, value := range values {
+			enriched.Header.Add(key, value)
+		}
+	}
+	r, err := h.client.Do(enriched)
+	if err != nil {
+		h.logger.Warn("HTTP request failed", zap.Error(err), zap.String("method", req.Method),
+			zap.String("url", req.URL.String()))
+	}
+	return r, err
+}
+
+func (h *httpClient) headerValue(name string) string {
+	return h.headers.Get(name)
+}

api/fx/ingestor/main.go

@@ -40,15 +40,15 @@ func main() {
 
 	application, err := app.New(logger, *configFile)
 	if err != nil {
-		logger.Fatal("Failed to initialise application", zap.Error(err))
-	}
-
-	if err := application.Run(ctx); err != nil {
-		if errors.Is(err, context.Canceled) {
-			logger.Info("FX ingestor stopped")
-			return
+		logger.Error("Failed to initialise application", zap.Error(err))
+	} else {
+		if err := application.Run(ctx); err != nil {
+			if errors.Is(err, context.Canceled) {
+				logger.Info("FX ingestor stopped")
+				return
+			}
+			logger.Error("Ingestor terminated with error", zap.Error(err))
 		}
-		logger.Fatal("Ingestor terminated with error", zap.Error(err))
 	}
 
 	logger.Info("FX ingestor stopped")

api/fx/oracle/go.mod

@@ -13,8 +13,8 @@ require (
 	github.com/tech/sendico/pkg v0.1.0
 	go.mongodb.org/mongo-driver v1.17.6
 	go.uber.org/zap v1.27.1
-	google.golang.org/grpc v1.77.0
-	google.golang.org/protobuf v1.36.10
+	google.golang.org/grpc v1.78.0
+	google.golang.org/protobuf v1.36.11
 	gopkg.in/yaml.v3 v3.0.1
 )
 
@@ -33,7 +33,7 @@ require (
 	github.com/mitchellh/mapstructure v1.5.0 // indirect
 	github.com/montanaflynn/stats v0.7.1 // indirect
 	github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 // indirect
-	github.com/nats-io/nats.go v1.47.0 // indirect
+	github.com/nats-io/nats.go v1.48.0 // indirect
 	github.com/nats-io/nkeys v0.4.12 // indirect
 	github.com/nats-io/nuid v1.0.1 // indirect
 	github.com/prometheus/client_model v0.6.2 // indirect
@@ -50,5 +50,5 @@ require (
 	golang.org/x/sync v0.19.0 // indirect
 	golang.org/x/sys v0.39.0 // indirect
 	golang.org/x/text v0.32.0 // indirect
-	google.golang.org/genproto/googleapis/rpc v0.0.0-20251202230838-ff82c1b0f217 // indirect
+	google.golang.org/genproto/googleapis/rpc v0.0.0-20251222181119-0a764e51fe1b // indirect
 )

api/fx/oracle/go.sum

@@ -95,8 +95,8 @@ github.com/morikuni/aec v1.0.0 h1:nP9CBfwrvYnBRgY6qfDQkygYDmYwOilePFkwzv4dU8A=
 github.com/morikuni/aec v1.0.0/go.mod h1:BbKIizmSmc5MMPqRYbxO4ZU0S0+P200+tUnFx7PXmsc=
 github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 h1:C3w9PqII01/Oq1c1nUAm88MOHcQC9l5mIlSMApZMrHA=
 github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822/go.mod h1:+n7T8mK8HuQTcFwEeznm/DIxMOiR9yIdICNftLE1DvQ=
-github.com/nats-io/nats.go v1.47.0 h1:YQdADw6J/UfGUd2Oy6tn4Hq6YHxCaJrVKayxxFqYrgM=
-github.com/nats-io/nats.go v1.47.0/go.mod h1:iRWIPokVIFbVijxuMQq4y9ttaBTMe0SFdlZfMDd+33g=
+github.com/nats-io/nats.go v1.48.0 h1:pSFyXApG+yWU/TgbKCjmm5K4wrHu86231/w84qRVR+U=
+github.com/nats-io/nats.go v1.48.0/go.mod h1:iRWIPokVIFbVijxuMQq4y9ttaBTMe0SFdlZfMDd+33g=
 github.com/nats-io/nkeys v0.4.12 h1:nssm7JKOG9/x4J8II47VWCL1Ds29avyiQDRn0ckMvDc=
 github.com/nats-io/nkeys v0.4.12/go.mod h1:MT59A1HYcjIcyQDJStTfaOY6vhy9XTUjOFo+SVsvpBg=
 github.com/nats-io/nuid v1.0.1 h1:5iA8DT8V7q8WK2EScv2padNa/rTESc1KdnPw4TC2paw=
@@ -212,12 +212,12 @@ golang.org/x/tools v0.1.12/go.mod h1:hNGJHUnrk76NpqgfD5Aqm5Crs+Hm0VOH/i9J2+nxYbc
 golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 gonum.org/v1/gonum v0.16.0 h1:5+ul4Swaf3ESvrOnidPp4GZbzf0mxVQpDCYUQE7OJfk=
 gonum.org/v1/gonum v0.16.0/go.mod h1:fef3am4MQ93R2HHpKnLk4/Tbh/s0+wqD5nfa6Pnwy4E=
-google.golang.org/genproto/googleapis/rpc v0.0.0-20251202230838-ff82c1b0f217 h1:gRkg/vSppuSQoDjxyiGfN4Upv/h/DQmIR10ZU8dh4Ww=
-google.golang.org/genproto/googleapis/rpc v0.0.0-20251202230838-ff82c1b0f217/go.mod h1:7i2o+ce6H/6BluujYR+kqX3GKH+dChPTQU19wjRPiGk=
-google.golang.org/grpc v1.77.0 h1:wVVY6/8cGA6vvffn+wWK5ToddbgdU3d8MNENr4evgXM=
-google.golang.org/grpc v1.77.0/go.mod h1:z0BY1iVj0q8E1uSQCjL9cppRj+gnZjzDnzV0dHhrNig=
-google.golang.org/protobuf v1.36.10 h1:AYd7cD/uASjIL6Q9LiTjz8JLcrh/88q5UObnmY3aOOE=
-google.golang.org/protobuf v1.36.10/go.mod h1:HTf+CrKn2C3g5S8VImy6tdcUvCska2kB7j23XfzDpco=
+google.golang.org/genproto/googleapis/rpc v0.0.0-20251222181119-0a764e51fe1b h1:Mv8VFug0MP9e5vUxfBcE3vUkV6CImK3cMNMIDFjmzxU=
+google.golang.org/genproto/googleapis/rpc v0.0.0-20251222181119-0a764e51fe1b/go.mod h1:j9x/tPzZkyxcgEFkiKEEGxfvyumM01BEtsW8xzOahRQ=
+google.golang.org/grpc v1.78.0 h1:K1XZG/yGDJnzMdd/uZHAkVqJE+xIDOcmdSFZkBUicNc=
+google.golang.org/grpc v1.78.0/go.mod h1:I47qjTo4OKbMkjA/aOOwxDIiPSBofUtQUI5EfpWvW7U=
+google.golang.org/protobuf v1.36.11 h1:fV6ZwhNocDyBLK0dj+fg8ektcVegBBuEolpbTQyBNVE=
+google.golang.org/protobuf v1.36.11/go.mod h1:HTf+CrKn2C3g5S8VImy6tdcUvCska2kB7j23XfzDpco=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c h1:Hei/4ADfdWqJk1ZMxUNpqntNwaWcugrBjAiHlqqRiVk=
 gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c/go.mod h1:JHkPIbrfpd72SG/EVd6muEfDQjcINNoR0C8j2r3qZ4Q=

api/fx/oracle/internal/service/oracle/logging.go

@@ -0,0 +1,90 @@
+package oracle
+
+import (
+	"strings"
+
+	fxv1 "github.com/tech/sendico/pkg/proto/common/fx/v1"
+	moneyv1 "github.com/tech/sendico/pkg/proto/common/money/v1"
+	tracev1 "github.com/tech/sendico/pkg/proto/common/trace/v1"
+	oraclev1 "github.com/tech/sendico/pkg/proto/oracle/v1"
+	"go.uber.org/zap"
+)
+
+func quoteRequestFields(req *oraclev1.GetQuoteRequest) []zap.Field {
+	if req == nil {
+		return nil
+	}
+	fields := requestMetaFields(req.GetMeta())
+	if pair := req.GetPair(); pair != nil {
+		if base := strings.TrimSpace(pair.GetBase()); base != "" {
+			fields = append(fields, zap.String("pair_base", base))
+		}
+		if quote := strings.TrimSpace(pair.GetQuote()); quote != "" {
+			fields = append(fields, zap.String("pair_quote", quote))
+		}
+	}
+	if side := req.GetSide(); side != fxv1.Side_SIDE_UNSPECIFIED {
+		fields = append(fields, zap.String("side", side.String()))
+	}
+	if req.GetFirm() {
+		fields = append(fields, zap.Bool("firm", req.GetFirm()))
+	}
+	if ttl := req.GetTtlMs(); ttl > 0 {
+		fields = append(fields, zap.Int64("ttl_ms", ttl))
+	}
+	if maxAge := req.GetMaxAgeMs(); maxAge > 0 {
+		fields = append(fields, zap.Int32("max_age_ms", maxAge))
+	}
+	if provider := strings.TrimSpace(req.GetPreferredProvider()); provider != "" {
+		fields = append(fields, zap.String("preferred_provider", provider))
+	}
+	fields = append(fields, moneyFields("base_amount", req.GetBaseAmount())...)
+	fields = append(fields, moneyFields("quote_amount", req.GetQuoteAmount())...)
+	return fields
+}
+
+func requestMetaFields(meta *oraclev1.RequestMeta) []zap.Field {
+	if meta == nil {
+		return nil
+	}
+	fields := make([]zap.Field, 0, 4)
+	if org := strings.TrimSpace(meta.GetOrganizationRef()); org != "" {
+		fields = append(fields, zap.String("organization_ref", org))
+	}
+	if tenant := strings.TrimSpace(meta.GetTenantRef()); tenant != "" {
+		fields = append(fields, zap.String("tenant_ref", tenant))
+	}
+	fields = append(fields, traceFields(meta.GetTrace())...)
+	return fields
+}
+
+func moneyFields(prefix string, money *moneyv1.Money) []zap.Field {
+	if money == nil {
+		return nil
+	}
+	fields := make([]zap.Field, 0, 2)
+	if amt := strings.TrimSpace(money.GetAmount()); amt != "" {
+		fields = append(fields, zap.String(prefix, amt))
+	}
+	if ccy := strings.TrimSpace(money.GetCurrency()); ccy != "" {
+		fields = append(fields, zap.String(prefix+"_currency", ccy))
+	}
+	return fields
+}
+
+func traceFields(trace *tracev1.TraceContext) []zap.Field {
+	if trace == nil {
+		return nil
+	}
+	fields := make([]zap.Field, 0, 3)
+	if ref := strings.TrimSpace(trace.GetTraceRef()); ref != "" {
+		fields = append(fields, zap.String("trace_ref", ref))
+	}
+	if idem := strings.TrimSpace(trace.GetIdempotencyKey()); idem != "" {
+		fields = append(fields, zap.String("idempotency_key", idem))
+	}
+	if req := strings.TrimSpace(trace.GetRequestRef()); req != "" {
+		fields = append(fields, zap.String("request_ref", req))
+	}
+	return fields
+}

api/fx/oracle/internal/service/oracle/service.go

@@ -101,22 +101,27 @@ func (s *Service) getQuoteResponder(ctx context.Context, req *oraclev1.GetQuoteR
 	if req == nil {
 		req = &oraclev1.GetQuoteRequest{}
 	}
-	s.logger.Debug("Handling GetQuote", zap.String("pair", req.GetPair().GetBase()+"/"+req.GetPair().GetQuote()), zap.Bool("firm", req.GetFirm()))
+	logger := s.logger.With(quoteRequestFields(req)...)
+	logger.Debug("Handling GetQuote")
 	if req.GetSide() == fxv1.Side_SIDE_UNSPECIFIED {
+		logger.Warn("GetQuote invalid: side missing")
 		return gsresponse.InvalidArgument[oraclev1.GetQuoteResponse](s.logger, mservice.FXOracle, errSideRequired)
 	}
 	if req.GetBaseAmount() != nil && req.GetQuoteAmount() != nil {
+		logger.Warn("GetQuote invalid: both base_amount and quote_amount provided")
 		return gsresponse.InvalidArgument[oraclev1.GetQuoteResponse](s.logger, mservice.FXOracle, errAmountsMutuallyExclusive)
 	}
 	if req.GetBaseAmount() == nil && req.GetQuoteAmount() == nil {
+		logger.Warn("GetQuote invalid: amount missing")
 		return gsresponse.InvalidArgument[oraclev1.GetQuoteResponse](s.logger, mservice.FXOracle, errAmountRequired)
 	}
 	if err := s.pingStorage(ctx); err != nil {
-		s.logger.Warn("Storage unavailable during GetQuote", zap.Error(err))
+		logger.Warn("Storage unavailable during GetQuote", zap.Error(err))
 		return gsresponse.Unavailable[oraclev1.GetQuoteResponse](s.logger, mservice.FXOracle, err)
 	}
 	pairMsg := req.GetPair()
 	if pairMsg == nil || strings.TrimSpace(pairMsg.GetBase()) == "" || strings.TrimSpace(pairMsg.GetQuote()) == "" {
+		logger.Warn("GetQuote invalid: pair missing")
 		return gsresponse.InvalidArgument[oraclev1.GetQuoteResponse](s.logger, mservice.FXOracle, errEmptyRequest)
 	}
 	pairKey := model.CurrencyPair{Base: strings.ToUpper(pairMsg.GetBase()), Quote: strings.ToUpper(pairMsg.GetQuote())}
@@ -125,8 +130,10 @@ func (s *Service) getQuoteResponder(ctx context.Context, req *oraclev1.GetQuoteR
 	if err != nil {
 		switch {
 		case errors.Is(err, merrors.ErrNoData):
+			logger.Warn("pair not supported", zap.String("pair", pairKey.Base+"/"+pairKey.Quote))
 			return gsresponse.InvalidArgument[oraclev1.GetQuoteResponse](s.logger, mservice.FXOracle, merrors.InvalidArgument("pair_not_supported"))
 		default:
+			logger.Warn("GetQuote failed to load pair", zap.Error(err))
 			return gsresponse.Internal[oraclev1.GetQuoteResponse](s.logger, mservice.FXOracle, err)
 		}
 	}
@@ -143,8 +150,10 @@ func (s *Service) getQuoteResponder(ctx context.Context, req *oraclev1.GetQuoteR
 	if err != nil {
 		switch {
 		case errors.Is(err, merrors.ErrNoData):
+			logger.Warn("rate not found", zap.String("pair", pairKey.Base+"/"+pairKey.Quote), zap.String("provider", provider))
 			return gsresponse.FailedPrecondition[oraclev1.GetQuoteResponse](s.logger, mservice.FXOracle, "rate_not_found", err)
 		default:
+			logger.Warn("GetQuote failed to load rate", zap.Error(err), zap.String("pair", pairKey.Base+"/"+pairKey.Quote), zap.String("provider", provider))
 			return gsresponse.Internal[oraclev1.GetQuoteResponse](s.logger, mservice.FXOracle, err)
 		}
 	}
@@ -153,27 +162,31 @@ func (s *Service) getQuoteResponder(ctx context.Context, req *oraclev1.GetQuoteR
 	if maxAge := req.GetMaxAgeMs(); maxAge > 0 {
 		age := now.UnixMilli() - rate.AsOfUnixMs
 		if age > int64(maxAge) {
-			s.logger.Warn("Rate snapshot stale", zap.Int64("age_ms", age), zap.Int32("max_age_ms", req.GetMaxAgeMs()), zap.String("pair", pairKey.Base+"/"+pairKey.Quote), zap.String("provider", provider))
+			logger.Warn("Rate snapshot stale", zap.Int64("age_ms", age), zap.Int32("max_age_ms", req.GetMaxAgeMs()), zap.String("pair", pairKey.Base+"/"+pairKey.Quote), zap.String("provider", provider))
 			return gsresponse.FailedPrecondition[oraclev1.GetQuoteResponse](s.logger, mservice.FXOracle, "stale_rate", merrors.InvalidArgument("rate older than allowed window"))
 		}
 	}
 
 	comp, err := newQuoteComputation(pair, rate, req.GetSide(), provider)
 	if err != nil {
+		logger.Warn("GetQuote invalid input", zap.Error(err))
 		return gsresponse.InvalidArgument[oraclev1.GetQuoteResponse](s.logger, mservice.FXOracle, err)
 	}
 
 	if req.GetBaseAmount() != nil {
 		if err := comp.withBaseInput(req.GetBaseAmount()); err != nil {
+			logger.Warn("GetQuote invalid base input", zap.Error(err))
 			return gsresponse.InvalidArgument[oraclev1.GetQuoteResponse](s.logger, mservice.FXOracle, err)
 		}
 	} else if req.GetQuoteAmount() != nil {
 		if err := comp.withQuoteInput(req.GetQuoteAmount()); err != nil {
+			logger.Warn("GetQuote invalid quote input", zap.Error(err))
 			return gsresponse.InvalidArgument[oraclev1.GetQuoteResponse](s.logger, mservice.FXOracle, err)
 		}
 	}
 
 	if err := comp.compute(); err != nil {
+		logger.Warn("GetQuote computation failed", zap.Error(err))
 		return gsresponse.Internal[oraclev1.GetQuoteResponse](s.logger, mservice.FXOracle, err)
 	}
 
@@ -195,12 +208,14 @@ func (s *Service) getQuoteResponder(ctx context.Context, req *oraclev1.GetQuoteR
 		if err := s.storage.Quotes().Issue(ctx, quoteModel); err != nil {
 			switch {
 			case errors.Is(err, merrors.ErrDataConflict):
+				logger.Warn("GetQuote conflict issuing firm quote", zap.Error(err), zap.String("quote_ref", quoteModel.QuoteRef))
 				return gsresponse.Conflict[oraclev1.GetQuoteResponse](s.logger, mservice.FXOracle, err)
 			default:
+				logger.Warn("GetQuote failed to issue firm quote", zap.Error(err), zap.String("quote_ref", quoteModel.QuoteRef))
 				return gsresponse.Internal[oraclev1.GetQuoteResponse](s.logger, mservice.FXOracle, err)
 			}
 		}
-		s.logger.Info("Firm quote stored", zap.String("quote_ref", quoteModel.QuoteRef), zap.String("pair", pairKey.Base+"/"+pairKey.Quote), zap.String("provider", quoteModel.Provider), zap.Int64("expires_at_ms", quoteModel.ExpiresAtUnixMs))
+		logger.Info("Firm quote stored", zap.String("quote_ref", quoteModel.QuoteRef), zap.String("pair", pairKey.Base+"/"+pairKey.Quote), zap.String("provider", quoteModel.Provider), zap.Int64("expires_at_ms", quoteModel.ExpiresAtUnixMs))
 	}
 
 	resp := &oraclev1.GetQuoteResponse{
@@ -214,18 +229,24 @@ func (s *Service) validateQuoteResponder(ctx context.Context, req *oraclev1.Vali
 	if req == nil {
 		req = &oraclev1.ValidateQuoteRequest{}
 	}
-	s.logger.Debug("Handling ValidateQuote", zap.String("quote_ref", req.GetQuoteRef()))
+	logger := s.logger.With(requestMetaFields(req.GetMeta())...)
+	if ref := strings.TrimSpace(req.GetQuoteRef()); ref != "" {
+		logger = logger.With(zap.String("quote_ref", ref))
+	}
+	logger.Debug("Handling ValidateQuote")
 	if req.GetQuoteRef() == "" {
+		logger.Warn("ValidateQuote invalid: quote_ref missing")
 		return gsresponse.InvalidArgument[oraclev1.ValidateQuoteResponse](s.logger, mservice.FXOracle, errQuoteRefRequired)
 	}
 	if err := s.pingStorage(ctx); err != nil {
-		s.logger.Warn("Storage unavailable during ValidateQuote", zap.Error(err))
+		logger.Warn("Storage unavailable during ValidateQuote", zap.Error(err))
 		return gsresponse.Unavailable[oraclev1.ValidateQuoteResponse](s.logger, mservice.FXOracle, err)
 	}
 	quote, err := s.storage.Quotes().GetByRef(ctx, req.GetQuoteRef())
 	if err != nil {
 		switch {
 		case errors.Is(err, merrors.ErrNoData):
+			logger.Warn("ValidateQuote: quote not found", zap.String("quote_ref", req.GetQuoteRef()))
 			resp := &oraclev1.ValidateQuoteResponse{
 				Meta:   buildResponseMeta(req.GetMeta()),
 				Quote:  nil,
@@ -234,6 +255,7 @@ func (s *Service) validateQuoteResponder(ctx context.Context, req *oraclev1.Vali
 			}
 			return gsresponse.Success(resp)
 		default:
+			logger.Warn("ValidateQuote failed", zap.Error(err))
 			return gsresponse.Internal[oraclev1.ValidateQuoteResponse](s.logger, mservice.FXOracle, err)
 		}
 	}
@@ -255,6 +277,11 @@ func (s *Service) validateQuoteResponder(ctx context.Context, req *oraclev1.Vali
 		Valid:  valid,
 		Reason: reason,
 	}
+	if !valid {
+		logger.Info("ValidateQuote invalid", zap.String("reason", reason), zap.Bool("firm", quote.Firm))
+	} else {
+		logger.Debug("ValidateQuote valid", zap.Bool("firm", quote.Firm))
+	}
 	return gsresponse.Success(resp)
 }
 
@@ -262,29 +289,43 @@ func (s *Service) consumeQuoteResponder(ctx context.Context, req *oraclev1.Consu
 	if req == nil {
 		req = &oraclev1.ConsumeQuoteRequest{}
 	}
-	s.logger.Debug("Handling ConsumeQuote", zap.String("quote_ref", req.GetQuoteRef()), zap.String("ledger_txn_ref", req.GetLedgerTxnRef()))
+	logger := s.logger.With(requestMetaFields(req.GetMeta())...)
+	if ref := strings.TrimSpace(req.GetQuoteRef()); ref != "" {
+		logger = logger.With(zap.String("quote_ref", ref))
+	}
+	if ledger := strings.TrimSpace(req.GetLedgerTxnRef()); ledger != "" {
+		logger = logger.With(zap.String("ledger_txn_ref", ledger))
+	}
+	logger.Debug("Handling ConsumeQuote")
 	if req.GetQuoteRef() == "" {
+		logger.Warn("ConsumeQuote invalid: quote_ref missing")
 		return gsresponse.InvalidArgument[oraclev1.ConsumeQuoteResponse](s.logger, mservice.FXOracle, errQuoteRefRequired)
 	}
 	if req.GetLedgerTxnRef() == "" {
+		logger.Warn("ConsumeQuote invalid: ledger_txn_ref missing")
 		return gsresponse.InvalidArgument[oraclev1.ConsumeQuoteResponse](s.logger, mservice.FXOracle, errLedgerTxnRefRequired)
 	}
 	if err := s.pingStorage(ctx); err != nil {
-		s.logger.Warn("Storage unavailable during ConsumeQuote", zap.Error(err))
+		logger.Warn("Storage unavailable during ConsumeQuote", zap.Error(err))
 		return gsresponse.Unavailable[oraclev1.ConsumeQuoteResponse](s.logger, mservice.FXOracle, err)
 	}
 	_, err := s.storage.Quotes().Consume(ctx, req.GetQuoteRef(), req.GetLedgerTxnRef(), time.Now())
 	if err != nil {
 		switch {
 		case errors.Is(err, storage.ErrQuoteExpired):
+			logger.Warn("ConsumeQuote failed: expired")
 			return gsresponse.FailedPrecondition[oraclev1.ConsumeQuoteResponse](s.logger, mservice.FXOracle, "expired", err)
 		case errors.Is(err, storage.ErrQuoteConsumed):
+			logger.Warn("ConsumeQuote failed: already consumed")
 			return gsresponse.FailedPrecondition[oraclev1.ConsumeQuoteResponse](s.logger, mservice.FXOracle, "consumed", err)
 		case errors.Is(err, storage.ErrQuoteNotFirm):
+			logger.Warn("ConsumeQuote failed: quote not firm")
 			return gsresponse.FailedPrecondition[oraclev1.ConsumeQuoteResponse](s.logger, mservice.FXOracle, "not_firm", err)
 		case errors.Is(err, merrors.ErrNoData):
+			logger.Warn("ConsumeQuote failed: quote not found")
 			return gsresponse.NotFound[oraclev1.ConsumeQuoteResponse](s.logger, mservice.FXOracle, err)
 		default:
+			logger.Warn("ConsumeQuote failed", zap.Error(err))
 			return gsresponse.Internal[oraclev1.ConsumeQuoteResponse](s.logger, mservice.FXOracle, err)
 		}
 	}
@@ -294,7 +335,7 @@ func (s *Service) consumeQuoteResponder(ctx context.Context, req *oraclev1.Consu
 		Consumed: true,
 		Reason:   "consumed",
 	}
-	s.logger.Debug("Quote consumed", zap.String("quote_ref", req.GetQuoteRef()), zap.String("ledger_txn_ref", req.GetLedgerTxnRef()))
+	logger.Info("Quote consumed")
 	return gsresponse.Success(resp)
 }
 
@@ -302,13 +343,21 @@ func (s *Service) latestRateResponder(ctx context.Context, req *oraclev1.LatestR
 	if req == nil {
 		req = &oraclev1.LatestRateRequest{}
 	}
-	s.logger.Debug("Handling LatestRate", zap.String("pair", req.GetPair().GetBase()+"/"+req.GetPair().GetQuote()))
+	logger := s.logger.With(requestMetaFields(req.GetMeta())...)
+	if pair := req.GetPair(); pair != nil {
+		logger = logger.With(zap.String("pair_base", strings.TrimSpace(pair.GetBase())), zap.String("pair_quote", strings.TrimSpace(pair.GetQuote())))
+	}
+	if provider := strings.TrimSpace(req.GetProvider()); provider != "" {
+		logger = logger.With(zap.String("provider", provider))
+	}
+	logger.Debug("Handling LatestRate")
 	if err := s.pingStorage(ctx); err != nil {
-		s.logger.Warn("Storage unavailable during LatestRate", zap.Error(err))
+		logger.Warn("Storage unavailable during LatestRate", zap.Error(err))
 		return gsresponse.Unavailable[oraclev1.LatestRateResponse](s.logger, mservice.FXOracle, err)
 	}
 	pairMsg := req.GetPair()
 	if pairMsg == nil || strings.TrimSpace(pairMsg.GetBase()) == "" || strings.TrimSpace(pairMsg.GetQuote()) == "" {
+		logger.Warn("LatestRate invalid: pair missing")
 		return gsresponse.InvalidArgument[oraclev1.LatestRateResponse](s.logger, mservice.FXOracle, errEmptyRequest)
 	}
 	pair := model.CurrencyPair{Base: strings.ToUpper(pairMsg.GetBase()), Quote: strings.ToUpper(pairMsg.GetQuote())}
@@ -317,8 +366,10 @@ func (s *Service) latestRateResponder(ctx context.Context, req *oraclev1.LatestR
 	if err != nil {
 		switch {
 		case errors.Is(err, merrors.ErrNoData):
+			logger.Warn("LatestRate pair not found")
 			return gsresponse.NotFound[oraclev1.LatestRateResponse](s.logger, mservice.FXOracle, err)
 		default:
+			logger.Warn("LatestRate failed to load pair", zap.Error(err))
 			return gsresponse.Internal[oraclev1.LatestRateResponse](s.logger, mservice.FXOracle, err)
 		}
 	}
@@ -335,8 +386,10 @@ func (s *Service) latestRateResponder(ctx context.Context, req *oraclev1.LatestR
 	if err != nil {
 		switch {
 		case errors.Is(err, merrors.ErrNoData):
+			logger.Warn("LatestRate not found", zap.String("provider", provider))
 			return gsresponse.NotFound[oraclev1.LatestRateResponse](s.logger, mservice.FXOracle, err)
 		default:
+			logger.Warn("LatestRate failed", zap.Error(err))
 			return gsresponse.Internal[oraclev1.LatestRateResponse](s.logger, mservice.FXOracle, err)
 		}
 	}
@@ -345,6 +398,7 @@ func (s *Service) latestRateResponder(ctx context.Context, req *oraclev1.LatestR
 		Meta: buildResponseMeta(req.GetMeta()),
 		Rate: rateModelToProto(rate),
 	}
+	logger.Debug("LatestRate succeeded", zap.String("provider", provider), zap.Int64("asof_unix_ms", rate.AsOfUnixMs))
 	return gsresponse.Success(resp)
 }
 
@@ -352,13 +406,15 @@ func (s *Service) listPairsResponder(ctx context.Context, req *oraclev1.ListPair
 	if req == nil {
 		req = &oraclev1.ListPairsRequest{}
 	}
-	s.logger.Debug("Handling ListPairs")
+	logger := s.logger.With(requestMetaFields(req.GetMeta())...)
+	logger.Debug("Handling ListPairs")
 	if err := s.pingStorage(ctx); err != nil {
-		s.logger.Warn("Storage unavailable during ListPairs", zap.Error(err))
+		logger.Warn("Storage unavailable during ListPairs", zap.Error(err))
 		return gsresponse.Unavailable[oraclev1.ListPairsResponse](s.logger, mservice.FXOracle, err)
 	}
 	pairs, err := s.storage.Pairs().ListEnabled(ctx)
 	if err != nil {
+		logger.Warn("ListPairs failed", zap.Error(err))
 		return gsresponse.Internal[oraclev1.ListPairsResponse](s.logger, mservice.FXOracle, err)
 	}
 	result := make([]*oraclev1.PairMeta, 0, len(pairs))
@@ -369,7 +425,7 @@ func (s *Service) listPairsResponder(ctx context.Context, req *oraclev1.ListPair
 		Meta:  buildResponseMeta(req.GetMeta()),
 		Pairs: result,
 	}
-	s.logger.Debug("ListPairs returning metadata", zap.Int("pairs", len(resp.GetPairs())))
+	logger.Debug("ListPairs returning metadata", zap.Int("pairs", len(resp.GetPairs())))
 	return gsresponse.Success(resp)
 }
 

api/fx/storage/go.mod

@@ -28,5 +28,5 @@ require (
 	golang.org/x/crypto v0.46.0 // indirect
 	golang.org/x/sync v0.19.0 // indirect
 	golang.org/x/text v0.32.0 // indirect
-	google.golang.org/protobuf v1.36.10 // indirect
+	google.golang.org/protobuf v1.36.11 // indirect
 )

api/fx/storage/go.sum

@@ -169,7 +169,7 @@ golang.org/x/tools v0.0.0-20190425150028-36563e24a262/go.mod h1:RgjU9mgBXZiqYHBn
 golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
 golang.org/x/tools v0.1.12/go.mod h1:hNGJHUnrk76NpqgfD5Aqm5Crs+Hm0VOH/i9J2+nxYbc=
 golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
-google.golang.org/protobuf v1.36.10 h1:AYd7cD/uASjIL6Q9LiTjz8JLcrh/88q5UObnmY3aOOE=
-google.golang.org/protobuf v1.36.10/go.mod h1:HTf+CrKn2C3g5S8VImy6tdcUvCska2kB7j23XfzDpco=
+google.golang.org/protobuf v1.36.11 h1:fV6ZwhNocDyBLK0dj+fg8ektcVegBBuEolpbTQyBNVE=
+google.golang.org/protobuf v1.36.11/go.mod h1:HTf+CrKn2C3g5S8VImy6tdcUvCska2kB7j23XfzDpco=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

api/gateway/chain/client/client.go

@@ -24,6 +24,8 @@ type Client interface {
 	GetTransfer(ctx context.Context, req *chainv1.GetTransferRequest) (*chainv1.GetTransferResponse, error)
 	ListTransfers(ctx context.Context, req *chainv1.ListTransfersRequest) (*chainv1.ListTransfersResponse, error)
 	EstimateTransferFee(ctx context.Context, req *chainv1.EstimateTransferFeeRequest) (*chainv1.EstimateTransferFeeResponse, error)
+	ComputeGasTopUp(ctx context.Context, req *chainv1.ComputeGasTopUpRequest) (*chainv1.ComputeGasTopUpResponse, error)
+	EnsureGasTopUp(ctx context.Context, req *chainv1.EnsureGasTopUpRequest) (*chainv1.EnsureGasTopUpResponse, error)
 	Close() error
 }
 
@@ -36,6 +38,8 @@ type grpcGatewayClient interface {
 	GetTransfer(ctx context.Context, in *chainv1.GetTransferRequest, opts ...grpc.CallOption) (*chainv1.GetTransferResponse, error)
 	ListTransfers(ctx context.Context, in *chainv1.ListTransfersRequest, opts ...grpc.CallOption) (*chainv1.ListTransfersResponse, error)
 	EstimateTransferFee(ctx context.Context, in *chainv1.EstimateTransferFeeRequest, opts ...grpc.CallOption) (*chainv1.EstimateTransferFeeResponse, error)
+	ComputeGasTopUp(ctx context.Context, in *chainv1.ComputeGasTopUpRequest, opts ...grpc.CallOption) (*chainv1.ComputeGasTopUpResponse, error)
+	EnsureGasTopUp(ctx context.Context, in *chainv1.EnsureGasTopUpRequest, opts ...grpc.CallOption) (*chainv1.EnsureGasTopUpResponse, error)
 }
 
 type chainGatewayClient struct {
@@ -139,6 +143,18 @@ func (c *chainGatewayClient) EstimateTransferFee(ctx context.Context, req *chain
 	return c.client.EstimateTransferFee(ctx, req)
 }
 
+func (c *chainGatewayClient) ComputeGasTopUp(ctx context.Context, req *chainv1.ComputeGasTopUpRequest) (*chainv1.ComputeGasTopUpResponse, error) {
+	ctx, cancel := c.callContext(ctx)
+	defer cancel()
+	return c.client.ComputeGasTopUp(ctx, req)
+}
+
+func (c *chainGatewayClient) EnsureGasTopUp(ctx context.Context, req *chainv1.EnsureGasTopUpRequest) (*chainv1.EnsureGasTopUpResponse, error) {
+	ctx, cancel := c.callContext(ctx)
+	defer cancel()
+	return c.client.EnsureGasTopUp(ctx, req)
+}
+
 func (c *chainGatewayClient) callContext(ctx context.Context) (context.Context, context.CancelFunc) {
 	timeout := c.cfg.CallTimeout
 	if timeout <= 0 {

api/gateway/chain/client/fake.go

@@ -16,6 +16,8 @@ type Fake struct {
 	GetTransferFn         func(ctx context.Context, req *chainv1.GetTransferRequest) (*chainv1.GetTransferResponse, error)
 	ListTransfersFn       func(ctx context.Context, req *chainv1.ListTransfersRequest) (*chainv1.ListTransfersResponse, error)
 	EstimateTransferFeeFn func(ctx context.Context, req *chainv1.EstimateTransferFeeRequest) (*chainv1.EstimateTransferFeeResponse, error)
+	ComputeGasTopUpFn     func(ctx context.Context, req *chainv1.ComputeGasTopUpRequest) (*chainv1.ComputeGasTopUpResponse, error)
+	EnsureGasTopUpFn      func(ctx context.Context, req *chainv1.EnsureGasTopUpRequest) (*chainv1.EnsureGasTopUpResponse, error)
 	CloseFn               func() error
 }
 
@@ -75,6 +77,20 @@ func (f *Fake) EstimateTransferFee(ctx context.Context, req *chainv1.EstimateTra
 	return &chainv1.EstimateTransferFeeResponse{}, nil
 }
 
+func (f *Fake) ComputeGasTopUp(ctx context.Context, req *chainv1.ComputeGasTopUpRequest) (*chainv1.ComputeGasTopUpResponse, error) {
+	if f.ComputeGasTopUpFn != nil {
+		return f.ComputeGasTopUpFn(ctx, req)
+	}
+	return &chainv1.ComputeGasTopUpResponse{}, nil
+}
+
+func (f *Fake) EnsureGasTopUp(ctx context.Context, req *chainv1.EnsureGasTopUpRequest) (*chainv1.EnsureGasTopUpResponse, error) {
+	if f.EnsureGasTopUpFn != nil {
+		return f.EnsureGasTopUpFn(ctx, req)
+	}
+	return &chainv1.EnsureGasTopUpResponse{}, nil
+}
+
 func (f *Fake) Close() error {
 	if f.CloseFn != nil {
 		return f.CloseFn()

api/gateway/chain/config.yml

@@ -34,16 +34,23 @@ messaging:
     reconnect_wait: 5
 
 chains:
-  - name: arbitrum_one
-    rpc_url_env: CHAIN_GATEWAY_ARBITRUM_RPC_URL
+  - name: tron_mainnet
+    chain_id: 728126428 # 0x2b6653dc
+    native_token: TRX
+    rpc_url_env: CHAIN_GATEWAY_RPC_URL
+    gas_topup_policy:
+      buffer_percent: 0.10
+      min_native_balance_trx: 10
+      rounding_unit_trx: 1
+      max_topup_trx: 100
     tokens:
-      - symbol: USDC
-        contract: "0xaf88d065e77c8cc2239327c5edb3a432268e5831"
       - symbol: USDT
-        contract: "0xfd086bc7cd5c481dcc9c85ebe478a1c0b69fcbb9"
+        contract: "0xa614f803b6fd780986a42c78ec9c7f77e6ded13c"
+      - symbol: USDC
+        contract: "0x3487b63d30b5b2c87fb7ffa8bcfade38eaac1abe"
 
 service_wallet:
-  chain: arbitrum_one
+  chain: tron_mainnet
   address_env: CHAIN_GATEWAY_SERVICE_WALLET_ADDRESS
   private_key_env: CHAIN_GATEWAY_SERVICE_WALLET_KEY
 
@@ -58,3 +65,4 @@ key_management:
 
 cache:
   wallet_balance_ttl_seconds: 120
+  rpc_request_timeout_seconds: 15

api/gateway/chain/go.mod

@@ -15,14 +15,14 @@ require (
 	github.com/tech/sendico/pkg v0.1.0
 	go.mongodb.org/mongo-driver v1.17.6
 	go.uber.org/zap v1.27.1
-	google.golang.org/grpc v1.77.0
-	google.golang.org/protobuf v1.36.10
+	google.golang.org/grpc v1.78.0
+	google.golang.org/protobuf v1.36.11
 	gopkg.in/yaml.v3 v3.0.1
 )
 
 require (
 	github.com/Microsoft/go-winio v0.6.2 // indirect
-	github.com/ProjectZKM/Ziren/crates/go-runtime/zkvm_runtime v0.0.0-20251208031133-be43a854e4be // indirect
+	github.com/ProjectZKM/Ziren/crates/go-runtime/zkvm_runtime v0.0.0-20251225023818-8886bb81c549 // indirect
 	github.com/beorn7/perks v1.0.1 // indirect
 	github.com/bits-and-blooms/bitset v1.24.4 // indirect
 	github.com/bmatcuk/doublestar/v4 v4.9.1 // indirect
@@ -60,7 +60,7 @@ require (
 	github.com/mitchellh/go-homedir v1.1.0 // indirect
 	github.com/montanaflynn/stats v0.7.1 // indirect
 	github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 // indirect
-	github.com/nats-io/nats.go v1.47.0 // indirect
+	github.com/nats-io/nats.go v1.48.0 // indirect
 	github.com/nats-io/nkeys v0.4.12 // indirect
 	github.com/nats-io/nuid v1.0.1 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
@@ -86,5 +86,5 @@ require (
 	golang.org/x/sys v0.39.0 // indirect
 	golang.org/x/text v0.32.0 // indirect
 	golang.org/x/time v0.14.0 // indirect
-	google.golang.org/genproto/googleapis/rpc v0.0.0-20251202230838-ff82c1b0f217 // indirect
+	google.golang.org/genproto/googleapis/rpc v0.0.0-20251222181119-0a764e51fe1b // indirect
 )

api/gateway/chain/go.sum

@@ -6,8 +6,8 @@ github.com/DataDog/zstd v1.4.5 h1:EndNeuB0l9syBZhut0wns3gV1hL8zX8LIu6ZiVHWLIQ=
 github.com/DataDog/zstd v1.4.5/go.mod h1:1jcaCB/ufaK+sKp1NBhlGmpz41jOoPQ35bpF36t7BBo=
 github.com/Microsoft/go-winio v0.6.2 h1:F2VQgta7ecxGYO8k3ZZz3RS8fVIXVxONVUPlNERoyfY=
 github.com/Microsoft/go-winio v0.6.2/go.mod h1:yd8OoFMLzJbo9gZq8j5qaps8bJ9aShtEA8Ipt1oGCvU=
-github.com/ProjectZKM/Ziren/crates/go-runtime/zkvm_runtime v0.0.0-20251208031133-be43a854e4be h1:1LtMLkGIqE5IQZ7Vdh4zv8A6LECInKF86/fTVxKxYLE=
-github.com/ProjectZKM/Ziren/crates/go-runtime/zkvm_runtime v0.0.0-20251208031133-be43a854e4be/go.mod h1:ioLG6R+5bUSO1oeGSDxOV3FADARuMoytZCSX6MEMQkI=
+github.com/ProjectZKM/Ziren/crates/go-runtime/zkvm_runtime v0.0.0-20251225023818-8886bb81c549 h1:NERDcANvDCnspxdMEMLXOMnuITWIWrTQvvhEA8ewBBM=
+github.com/ProjectZKM/Ziren/crates/go-runtime/zkvm_runtime v0.0.0-20251225023818-8886bb81c549/go.mod h1:ioLG6R+5bUSO1oeGSDxOV3FADARuMoytZCSX6MEMQkI=
 github.com/VictoriaMetrics/fastcache v1.13.0 h1:AW4mheMR5Vd9FkAPUv+NH6Nhw+fmbTMGMsNAoA/+4G0=
 github.com/VictoriaMetrics/fastcache v1.13.0/go.mod h1:hHXhl4DA2fTL2HTZDJFXWgW0LNjo6B+4aj2Wmng3TjU=
 github.com/beorn7/perks v1.0.1 h1:VlbKKnNfV8bJzeqoa4cOKqO6bYr3WgKZxO8Z16+hsOM=
@@ -207,8 +207,8 @@ github.com/morikuni/aec v1.0.0 h1:nP9CBfwrvYnBRgY6qfDQkygYDmYwOilePFkwzv4dU8A=
 github.com/morikuni/aec v1.0.0/go.mod h1:BbKIizmSmc5MMPqRYbxO4ZU0S0+P200+tUnFx7PXmsc=
 github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 h1:C3w9PqII01/Oq1c1nUAm88MOHcQC9l5mIlSMApZMrHA=
 github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822/go.mod h1:+n7T8mK8HuQTcFwEeznm/DIxMOiR9yIdICNftLE1DvQ=
-github.com/nats-io/nats.go v1.47.0 h1:YQdADw6J/UfGUd2Oy6tn4Hq6YHxCaJrVKayxxFqYrgM=
-github.com/nats-io/nats.go v1.47.0/go.mod h1:iRWIPokVIFbVijxuMQq4y9ttaBTMe0SFdlZfMDd+33g=
+github.com/nats-io/nats.go v1.48.0 h1:pSFyXApG+yWU/TgbKCjmm5K4wrHu86231/w84qRVR+U=
+github.com/nats-io/nats.go v1.48.0/go.mod h1:iRWIPokVIFbVijxuMQq4y9ttaBTMe0SFdlZfMDd+33g=
 github.com/nats-io/nkeys v0.4.12 h1:nssm7JKOG9/x4J8II47VWCL1Ds29avyiQDRn0ckMvDc=
 github.com/nats-io/nkeys v0.4.12/go.mod h1:MT59A1HYcjIcyQDJStTfaOY6vhy9XTUjOFo+SVsvpBg=
 github.com/nats-io/nuid v1.0.1 h1:5iA8DT8V7q8WK2EScv2padNa/rTESc1KdnPw4TC2paw=
@@ -362,12 +362,12 @@ golang.org/x/tools v0.1.12/go.mod h1:hNGJHUnrk76NpqgfD5Aqm5Crs+Hm0VOH/i9J2+nxYbc
 golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 gonum.org/v1/gonum v0.16.0 h1:5+ul4Swaf3ESvrOnidPp4GZbzf0mxVQpDCYUQE7OJfk=
 gonum.org/v1/gonum v0.16.0/go.mod h1:fef3am4MQ93R2HHpKnLk4/Tbh/s0+wqD5nfa6Pnwy4E=
-google.golang.org/genproto/googleapis/rpc v0.0.0-20251202230838-ff82c1b0f217 h1:gRkg/vSppuSQoDjxyiGfN4Upv/h/DQmIR10ZU8dh4Ww=
-google.golang.org/genproto/googleapis/rpc v0.0.0-20251202230838-ff82c1b0f217/go.mod h1:7i2o+ce6H/6BluujYR+kqX3GKH+dChPTQU19wjRPiGk=
-google.golang.org/grpc v1.77.0 h1:wVVY6/8cGA6vvffn+wWK5ToddbgdU3d8MNENr4evgXM=
-google.golang.org/grpc v1.77.0/go.mod h1:z0BY1iVj0q8E1uSQCjL9cppRj+gnZjzDnzV0dHhrNig=
-google.golang.org/protobuf v1.36.10 h1:AYd7cD/uASjIL6Q9LiTjz8JLcrh/88q5UObnmY3aOOE=
-google.golang.org/protobuf v1.36.10/go.mod h1:HTf+CrKn2C3g5S8VImy6tdcUvCska2kB7j23XfzDpco=
+google.golang.org/genproto/googleapis/rpc v0.0.0-20251222181119-0a764e51fe1b h1:Mv8VFug0MP9e5vUxfBcE3vUkV6CImK3cMNMIDFjmzxU=
+google.golang.org/genproto/googleapis/rpc v0.0.0-20251222181119-0a764e51fe1b/go.mod h1:j9x/tPzZkyxcgEFkiKEEGxfvyumM01BEtsW8xzOahRQ=
+google.golang.org/grpc v1.78.0 h1:K1XZG/yGDJnzMdd/uZHAkVqJE+xIDOcmdSFZkBUicNc=
+google.golang.org/grpc v1.78.0/go.mod h1:I47qjTo4OKbMkjA/aOOwxDIiPSBofUtQUI5EfpWvW7U=
+google.golang.org/protobuf v1.36.11 h1:fV6ZwhNocDyBLK0dj+fg8ektcVegBBuEolpbTQyBNVE=
+google.golang.org/protobuf v1.36.11/go.mod h1:HTf+CrKn2C3g5S8VImy6tdcUvCska2kB7j23XfzDpco=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c h1:Hei/4ADfdWqJk1ZMxUNpqntNwaWcugrBjAiHlqqRiVk=
 gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c/go.mod h1:JHkPIbrfpd72SG/EVd6muEfDQjcINNoR0C8j2r3qZ4Q=

api/gateway/chain/internal/server/internal/serverimp.go

@@ -2,14 +2,18 @@ package serverimp
 
 import (
 	"context"
+	"fmt"
 	"os"
 	"strings"
 	"time"
 
 	"github.com/mitchellh/mapstructure"
+	"github.com/shopspring/decimal"
 	"github.com/tech/sendico/gateway/chain/internal/keymanager"
 	vaultmanager "github.com/tech/sendico/gateway/chain/internal/keymanager/vault"
 	gatewayservice "github.com/tech/sendico/gateway/chain/internal/service/gateway"
+	"github.com/tech/sendico/gateway/chain/internal/service/gateway/drivers"
+	"github.com/tech/sendico/gateway/chain/internal/service/gateway/rpcclient"
 	gatewayshared "github.com/tech/sendico/gateway/chain/internal/service/gateway/shared"
 	"github.com/tech/sendico/gateway/chain/storage"
 	gatewaymongo "github.com/tech/sendico/gateway/chain/storage/mongo"
@@ -30,6 +34,8 @@ type Imp struct {
 
 	config *config
 	app    *grpcapp.App[storage.Repository]
+
+	rpcClients *rpcclient.Clients
 }
 
 type config struct {
@@ -41,11 +47,12 @@ type config struct {
 }
 
 type chainConfig struct {
-	Name        string        `yaml:"name"`
-	RPCURLEnv   string        `yaml:"rpc_url_env"`
-	ChainID     uint64        `yaml:"chain_id"`
-	NativeToken string        `yaml:"native_token"`
-	Tokens      []tokenConfig `yaml:"tokens"`
+	Name           string                `yaml:"name"`
+	RPCURLEnv      string                `yaml:"rpc_url_env"`
+	ChainID        uint64                `yaml:"chain_id"`
+	NativeToken    string                `yaml:"native_token"`
+	Tokens         []tokenConfig         `yaml:"tokens"`
+	GasTopUpPolicy *gasTopUpPolicyConfig `yaml:"gas_topup_policy"`
 }
 
 type serviceWalletConfig struct {
@@ -61,6 +68,19 @@ type tokenConfig struct {
 	ContractEnv string `yaml:"contract_env"`
 }
 
+type gasTopUpPolicyConfig struct {
+	gasTopUpRuleConfig `yaml:",inline"`
+	Native             *gasTopUpRuleConfig `yaml:"native"`
+	Contract           *gasTopUpRuleConfig `yaml:"contract"`
+}
+
+type gasTopUpRuleConfig struct {
+	BufferPercent       float64 `yaml:"buffer_percent"`
+	MinNativeBalanceTRX float64 `yaml:"min_native_balance_trx"`
+	RoundingUnitTRX     float64 `yaml:"rounding_unit_trx"`
+	MaxTopUpTRX         float64 `yaml:"max_topup_trx"`
+}
+
 // Create initialises the chain gateway server implementation.
 func Create(logger mlogger.Logger, file string, debug bool) (*Imp, error) {
 	return &Imp{
@@ -84,6 +104,9 @@ func (i *Imp) Shutdown() {
 	defer cancel()
 
 	i.app.Shutdown(ctx)
+	if i.rpcClients != nil {
+		i.rpcClients.Close()
+	}
 }
 
 func (i *Imp) Start() error {
@@ -98,20 +121,34 @@ func (i *Imp) Start() error {
 	}
 
 	cl := i.logger.Named("config")
-	networkConfigs := resolveNetworkConfigs(cl.Named("network"), cfg.Chains)
+	networkConfigs, err := resolveNetworkConfigs(cl.Named("network"), cfg.Chains)
+	if err != nil {
+		i.logger.Error("invalid chain network configuration", zap.Error(err))
+		return err
+	}
+	rpcClients, err := rpcclient.Prepare(context.Background(), i.logger.Named("rpc"), networkConfigs)
+	if err != nil {
+		i.logger.Error("failed to prepare rpc clients", zap.Error(err))
+		return err
+	}
+	i.rpcClients = rpcClients
 	walletConfig := resolveServiceWallet(cl.Named("wallet"), cfg.ServiceWallet)
 	keyManager, err := resolveKeyManager(i.logger.Named("key_manager"), cfg.KeyManagement)
 	if err != nil {
 		return err
 	}
+	driverRegistry, err := drivers.NewRegistry(i.logger.Named("drivers"), networkConfigs)
+	if err != nil {
+		return err
+	}
 
 	serviceFactory := func(logger mlogger.Logger, repo storage.Repository, producer msg.Producer) (grpcapp.Service, error) {
-		executor := gatewayservice.NewOnChainExecutor(logger, keyManager)
 		opts := []gatewayservice.Option{
 			gatewayservice.WithNetworks(networkConfigs),
 			gatewayservice.WithServiceWallet(walletConfig),
 			gatewayservice.WithKeyManager(keyManager),
-			gatewayservice.WithTransferExecutor(executor),
+			gatewayservice.WithRPCClients(rpcClients),
+			gatewayservice.WithDriverRegistry(driverRegistry),
 			gatewayservice.WithSettings(cfg.Settings),
 		}
 		return gatewayservice.NewService(logger, repo, producer, opts...), nil
@@ -157,7 +194,7 @@ func (i *Imp) loadConfig() (*config, error) {
 	return cfg, nil
 }
 
-func resolveNetworkConfigs(logger mlogger.Logger, chains []chainConfig) []gatewayshared.Network {
+func resolveNetworkConfigs(logger mlogger.Logger, chains []chainConfig) ([]gatewayshared.Network, error) {
 	result := make([]gatewayshared.Network, 0, len(chains))
 	for _, chain := range chains {
 		if strings.TrimSpace(chain.Name) == "" {
@@ -166,7 +203,8 @@ func resolveNetworkConfigs(logger mlogger.Logger, chains []chainConfig) []gatewa
 		}
 		rpcURL := strings.TrimSpace(os.Getenv(chain.RPCURLEnv))
 		if rpcURL == "" {
-			logger.Warn("chain RPC endpoint not configured", zap.String("chain", chain.Name), zap.String("env", chain.RPCURLEnv))
+			logger.Error("RPC url not configured", zap.String("chain", chain.Name), zap.String("env", chain.RPCURLEnv))
+			return nil, merrors.InvalidArgument(fmt.Sprintf("chain RPC endpoint not configured (chain=%s env=%s)", chain.Name, chain.RPCURLEnv))
 		}
 		contracts := make([]gatewayshared.TokenContract, 0, len(chain.Tokens))
 		for _, token := range chain.Tokens {
@@ -194,15 +232,84 @@ func resolveNetworkConfigs(logger mlogger.Logger, chains []chainConfig) []gatewa
 			})
 		}
 
+		gasPolicy, err := buildGasTopUpPolicy(chain.Name, chain.GasTopUpPolicy)
+		if err != nil {
+			logger.Error("invalid gas top-up policy", zap.String("chain", chain.Name), zap.Error(err))
+			return nil, err
+		}
+
 		result = append(result, gatewayshared.Network{
-			Name:         chain.Name,
-			RPCURL:       rpcURL,
-			ChainID:      chain.ChainID,
-			NativeToken:  chain.NativeToken,
-			TokenConfigs: contracts,
+			Name:           chain.Name,
+			RPCURL:         rpcURL,
+			ChainID:        chain.ChainID,
+			NativeToken:    chain.NativeToken,
+			TokenConfigs:   contracts,
+			GasTopUpPolicy: gasPolicy,
 		})
 	}
-	return result
+	return result, nil
+}
+
+func buildGasTopUpPolicy(chainName string, cfg *gasTopUpPolicyConfig) (*gatewayshared.GasTopUpPolicy, error) {
+	if cfg == nil {
+		return nil, nil
+	}
+	defaultRule, defaultSet, err := parseGasTopUpRule(chainName, "default", cfg.gasTopUpRuleConfig)
+	if err != nil {
+		return nil, err
+	}
+	if !defaultSet {
+		return nil, merrors.InvalidArgument(fmt.Sprintf("chain %s gas_topup_policy is required", chainName))
+	}
+
+	policy := &gatewayshared.GasTopUpPolicy{
+		Default: defaultRule,
+	}
+
+	if cfg.Native != nil {
+		rule, set, err := parseGasTopUpRule(chainName, "native", *cfg.Native)
+		if err != nil {
+			return nil, err
+		}
+		if set {
+			policy.Native = &rule
+		}
+	}
+	if cfg.Contract != nil {
+		rule, set, err := parseGasTopUpRule(chainName, "contract", *cfg.Contract)
+		if err != nil {
+			return nil, err
+		}
+		if set {
+			policy.Contract = &rule
+		}
+	}
+
+	return policy, nil
+}
+
+func parseGasTopUpRule(chainName, label string, cfg gasTopUpRuleConfig) (gatewayshared.GasTopUpRule, bool, error) {
+	if cfg.BufferPercent == 0 && cfg.MinNativeBalanceTRX == 0 && cfg.RoundingUnitTRX == 0 && cfg.MaxTopUpTRX == 0 {
+		return gatewayshared.GasTopUpRule{}, false, nil
+	}
+	if cfg.BufferPercent < 0 {
+		return gatewayshared.GasTopUpRule{}, true, merrors.InvalidArgument(fmt.Sprintf("chain %s gas_topup_policy %s buffer_percent must be >= 0", chainName, label))
+	}
+	if cfg.MinNativeBalanceTRX < 0 {
+		return gatewayshared.GasTopUpRule{}, true, merrors.InvalidArgument(fmt.Sprintf("chain %s gas_topup_policy %s min_native_balance_trx must be >= 0", chainName, label))
+	}
+	if cfg.RoundingUnitTRX <= 0 {
+		return gatewayshared.GasTopUpRule{}, true, merrors.InvalidArgument(fmt.Sprintf("chain %s gas_topup_policy %s rounding_unit_trx must be > 0", chainName, label))
+	}
+	if cfg.MaxTopUpTRX <= 0 {
+		return gatewayshared.GasTopUpRule{}, true, merrors.InvalidArgument(fmt.Sprintf("chain %s gas_topup_policy %s max_topup_trx must be > 0", chainName, label))
+	}
+	return gatewayshared.GasTopUpRule{
+		BufferPercent:    decimal.NewFromFloat(cfg.BufferPercent),
+		MinNativeBalance: decimal.NewFromFloat(cfg.MinNativeBalanceTRX),
+		RoundingUnit:     decimal.NewFromFloat(cfg.RoundingUnitTRX),
+		MaxTopUp:         decimal.NewFromFloat(cfg.MaxTopUpTRX),
+	}, true, nil
 }
 
 func resolveServiceWallet(logger mlogger.Logger, cfg serviceWalletConfig) gatewayshared.ServiceWallet {

api/gateway/chain/internal/service/gateway/commands/registry.go

@@ -23,6 +23,8 @@ type Registry struct {
 	GetTransfer      Unary[chainv1.GetTransferRequest, chainv1.GetTransferResponse]
 	ListTransfers    Unary[chainv1.ListTransfersRequest, chainv1.ListTransfersResponse]
 	EstimateTransfer Unary[chainv1.EstimateTransferFeeRequest, chainv1.EstimateTransferFeeResponse]
+	ComputeGasTopUp  Unary[chainv1.ComputeGasTopUpRequest, chainv1.ComputeGasTopUpResponse]
+	EnsureGasTopUp   Unary[chainv1.EnsureGasTopUpRequest, chainv1.EnsureGasTopUpResponse]
 }
 
 type RegistryDeps struct {
@@ -40,5 +42,7 @@ func NewRegistry(deps RegistryDeps) Registry {
 		GetTransfer:         transfer.NewGetTransfer(deps.Transfer.WithLogger("transfer.get")),
 		ListTransfers:       transfer.NewListTransfers(deps.Transfer.WithLogger("transfer.list")),
 		EstimateTransfer:    transfer.NewEstimateTransfer(deps.Transfer.WithLogger("transfer.estimate_fee")),
+		ComputeGasTopUp:     transfer.NewComputeGasTopUp(deps.Transfer.WithLogger("gas_topup.compute")),
+		EnsureGasTopUp:      transfer.NewEnsureGasTopUp(deps.Transfer.WithLogger("gas_topup.ensure")),
 	}
 }

api/gateway/chain/internal/service/gateway/commands/transfer/deps.go

@@ -2,7 +2,10 @@ package transfer
 
 import (
 	"context"
+	"time"
 
+	"github.com/tech/sendico/gateway/chain/internal/service/gateway/drivers"
+	"github.com/tech/sendico/gateway/chain/internal/service/gateway/rpcclient"
 	"github.com/tech/sendico/gateway/chain/internal/service/gateway/shared"
 	"github.com/tech/sendico/gateway/chain/storage"
 	clockpkg "github.com/tech/sendico/pkg/clock"
@@ -11,9 +14,11 @@ import (
 
 type Deps struct {
 	Logger           mlogger.Logger
-	Networks         map[string]shared.Network
+	Drivers          *drivers.Registry
+	Networks         *rpcclient.Registry
 	Storage          storage.Repository
 	Clock            clockpkg.Clock
+	RPCTimeout       time.Duration
 	EnsureRepository func(context.Context) error
 	LaunchExecution  func(transferRef, sourceWalletRef string, network shared.Network)
 }

api/gateway/chain/internal/service/gateway/commands/transfer/destination.go

@@ -43,8 +43,22 @@ func resolveDestination(ctx context.Context, deps Deps, dest *chainv1.TransferDe
 		deps.Logger.Warn("destination external address missing")
 		return model.TransferDestination{}, merrors.InvalidArgument("destination is required")
 	}
+	if deps.Drivers == nil {
+		deps.Logger.Warn("chain drivers missing", zap.String("network", source.Network))
+		return model.TransferDestination{}, merrors.Internal("chain drivers not configured")
+	}
+	chainDriver, err := deps.Drivers.Driver(source.Network)
+	if err != nil {
+		deps.Logger.Warn("unsupported chain driver", zap.String("network", source.Network), zap.Error(err))
+		return model.TransferDestination{}, merrors.InvalidArgument("unsupported chain for wallet")
+	}
+	normalized, err := chainDriver.NormalizeAddress(external)
+	if err != nil {
+		deps.Logger.Warn("invalid external address", zap.Error(err))
+		return model.TransferDestination{}, err
+	}
 	return model.TransferDestination{
-		ExternalAddress: strings.ToLower(external),
+		ExternalAddress: normalized,
 		Memo:            strings.TrimSpace(dest.GetMemo()),
 	}, nil
 }

api/gateway/chain/internal/service/gateway/commands/transfer/destination_address.go

@@ -4,11 +4,12 @@ import (
 	"context"
 	"strings"
 
+	"github.com/tech/sendico/gateway/chain/internal/service/gateway/driver"
 	"github.com/tech/sendico/gateway/chain/storage/model"
 	"github.com/tech/sendico/pkg/merrors"
 )
 
-func destinationAddress(ctx context.Context, deps Deps, dest model.TransferDestination) (string, error) {
+func destinationAddress(ctx context.Context, deps Deps, chainDriver driver.Driver, dest model.TransferDestination) (string, error) {
 	if ref := strings.TrimSpace(dest.ManagedWalletRef); ref != "" {
 		wallet, err := deps.Storage.Wallets().Get(ctx, ref)
 		if err != nil {
@@ -17,10 +18,10 @@ func destinationAddress(ctx context.Context, deps Deps, dest model.TransferDesti
 		if strings.TrimSpace(wallet.DepositAddress) == "" {
 			return "", merrors.Internal("destination wallet missing deposit address")
 		}
-		return wallet.DepositAddress, nil
+		return chainDriver.NormalizeAddress(wallet.DepositAddress)
 	}
 	if addr := strings.TrimSpace(dest.ExternalAddress); addr != "" {
-		return strings.ToLower(addr), nil
+		return chainDriver.NormalizeAddress(addr)
 	}
 	return "", merrors.InvalidArgument("transfer destination address not resolved")
 }

api/gateway/chain/internal/service/gateway/commands/transfer/fee.go

@@ -3,22 +3,12 @@ package transfer
 import (
 	"context"
 	"errors"
-	"math/big"
 	"strings"
-	"time"
 
-	"github.com/ethereum/go-ethereum"
-	"github.com/ethereum/go-ethereum/accounts/abi"
-	"github.com/ethereum/go-ethereum/common"
-	"github.com/ethereum/go-ethereum/ethclient"
-	"github.com/shopspring/decimal"
-	"github.com/tech/sendico/gateway/chain/internal/service/gateway/shared"
-	"github.com/tech/sendico/gateway/chain/storage/model"
+	"github.com/tech/sendico/gateway/chain/internal/service/gateway/driver"
 	"github.com/tech/sendico/pkg/api/routers/gsresponse"
 	"github.com/tech/sendico/pkg/merrors"
-	"github.com/tech/sendico/pkg/mlogger"
 	"github.com/tech/sendico/pkg/mservice"
-	moneyv1 "github.com/tech/sendico/pkg/proto/common/money/v1"
 	chainv1 "github.com/tech/sendico/pkg/proto/gateway/chain/v1"
 	"go.uber.org/zap"
 )
@@ -63,11 +53,20 @@ func (c *estimateTransferFeeCommand) Execute(ctx context.Context, req *chainv1.E
 	}
 
 	networkKey := strings.ToLower(strings.TrimSpace(sourceWallet.Network))
-	networkCfg, ok := c.deps.Networks[networkKey]
+	networkCfg, ok := c.deps.Networks.Network(networkKey)
 	if !ok {
 		c.deps.Logger.Warn("unsupported chain", zap.String("network", networkKey))
 		return gsresponse.InvalidArgument[chainv1.EstimateTransferFeeResponse](c.deps.Logger, mservice.ChainGateway, merrors.InvalidArgument("unsupported chain for wallet"))
 	}
+	if c.deps.Drivers == nil {
+		c.deps.Logger.Warn("chain drivers missing", zap.String("network", networkKey))
+		return gsresponse.Internal[chainv1.EstimateTransferFeeResponse](c.deps.Logger, mservice.ChainGateway, merrors.Internal("chain drivers not configured"))
+	}
+	chainDriver, err := c.deps.Drivers.Driver(networkKey)
+	if err != nil {
+		c.deps.Logger.Warn("unsupported chain driver", zap.String("network", networkKey), zap.Error(err))
+		return gsresponse.InvalidArgument[chainv1.EstimateTransferFeeResponse](c.deps.Logger, mservice.ChainGateway, merrors.InvalidArgument("unsupported chain for wallet"))
+	}
 
 	dest, err := resolveDestination(ctx, c.deps, req.GetDestination(), sourceWallet)
 	if err != nil {
@@ -79,170 +78,30 @@ func (c *estimateTransferFeeCommand) Execute(ctx context.Context, req *chainv1.E
 		return gsresponse.InvalidArgument[chainv1.EstimateTransferFeeResponse](c.deps.Logger, mservice.ChainGateway, err)
 	}
 
-	destinationAddress, err := destinationAddress(ctx, c.deps, dest)
+	destinationAddress, err := destinationAddress(ctx, c.deps, chainDriver, dest)
 	if err != nil {
 		c.deps.Logger.Warn("failed to resolve destination address", zap.Error(err))
 		return gsresponse.InvalidArgument[chainv1.EstimateTransferFeeResponse](c.deps.Logger, mservice.ChainGateway, err)
 	}
 
-	feeMoney, err := estimateNetworkFee(ctx, c.deps.Logger, networkCfg, sourceWallet, destinationAddress, amount)
+	driverDeps := driver.Deps{
+		Logger:     c.deps.Logger,
+		Registry:   c.deps.Networks,
+		RPCTimeout: c.deps.RPCTimeout,
+	}
+	feeMoney, err := chainDriver.EstimateFee(ctx, driverDeps, networkCfg, sourceWallet, destinationAddress, amount)
 	if err != nil {
 		c.deps.Logger.Warn("fee estimation failed", zap.Error(err))
 		return gsresponse.Auto[chainv1.EstimateTransferFeeResponse](c.deps.Logger, mservice.ChainGateway, err)
 	}
 
+	contextLabel := "erc20_transfer"
+	if strings.TrimSpace(sourceWallet.ContractAddress) == "" {
+		contextLabel = "native_transfer"
+	}
 	resp := &chainv1.EstimateTransferFeeResponse{
 		NetworkFee:        feeMoney,
-		EstimationContext: "erc20_transfer",
+		EstimationContext: contextLabel,
 	}
 	return gsresponse.Success(resp)
 }
-
-func estimateNetworkFee(ctx context.Context, logger mlogger.Logger, network shared.Network, wallet *model.ManagedWallet, destination string, amount *moneyv1.Money) (*moneyv1.Money, error) {
-	rpcURL := strings.TrimSpace(network.RPCURL)
-	if rpcURL == "" {
-		return nil, merrors.InvalidArgument("network rpc url not configured")
-	}
-	if strings.TrimSpace(wallet.ContractAddress) == "" {
-		return nil, merrors.NotImplemented("native token transfers not supported")
-	}
-	if !common.IsHexAddress(wallet.ContractAddress) {
-		return nil, merrors.InvalidArgument("invalid token contract address")
-	}
-	if !common.IsHexAddress(wallet.DepositAddress) {
-		return nil, merrors.InvalidArgument("invalid source wallet address")
-	}
-	if !common.IsHexAddress(destination) {
-		return nil, merrors.InvalidArgument("invalid destination address")
-	}
-
-	client, err := ethclient.DialContext(ctx, rpcURL)
-	if err != nil {
-		return nil, merrors.Internal("failed to connect to rpc: " + err.Error())
-	}
-	defer client.Close()
-
-	timeoutCtx, cancel := context.WithTimeout(ctx, 15*time.Second)
-	defer cancel()
-
-	tokenABI, err := abi.JSON(strings.NewReader(erc20TransferABI))
-	if err != nil {
-		return nil, merrors.Internal("failed to parse erc20 abi: " + err.Error())
-	}
-	tokenAddr := common.HexToAddress(wallet.ContractAddress)
-	toAddr := common.HexToAddress(destination)
-	fromAddr := common.HexToAddress(wallet.DepositAddress)
-
-	decimals, err := erc20Decimals(timeoutCtx, client, tokenABI, tokenAddr)
-	if err != nil {
-		logger.Warn("failed to read token decimals", zap.Error(err))
-		return nil, err
-	}
-
-	amountBase, err := toBaseUnits(strings.TrimSpace(amount.GetAmount()), decimals)
-	if err != nil {
-		return nil, err
-	}
-
-	input, err := tokenABI.Pack("transfer", toAddr, amountBase)
-	if err != nil {
-		return nil, merrors.Internal("failed to encode transfer call: " + err.Error())
-	}
-
-	gasPrice, err := client.SuggestGasPrice(timeoutCtx)
-	if err != nil {
-		return nil, merrors.Internal("failed to suggest gas price: " + err.Error())
-	}
-
-	callMsg := ethereum.CallMsg{
-		From:     fromAddr,
-		To:       &tokenAddr,
-		GasPrice: gasPrice,
-		Data:     input,
-	}
-	gasLimit, err := client.EstimateGas(timeoutCtx, callMsg)
-	if err != nil {
-		return nil, merrors.Internal("failed to estimate gas: " + err.Error())
-	}
-
-	fee := new(big.Int).Mul(gasPrice, new(big.Int).SetUint64(gasLimit))
-	feeDec := decimal.NewFromBigInt(fee, 0)
-
-	currency := strings.ToUpper(strings.TrimSpace(network.NativeToken))
-	if currency == "" {
-		currency = strings.ToUpper(network.Name)
-	}
-
-	return &moneyv1.Money{
-		Currency: currency,
-		Amount:   feeDec.String(),
-	}, nil
-}
-
-func erc20Decimals(ctx context.Context, client *ethclient.Client, tokenABI abi.ABI, token common.Address) (uint8, error) {
-	callData, err := tokenABI.Pack("decimals")
-	if err != nil {
-		return 0, merrors.Internal("failed to encode decimals call: " + err.Error())
-	}
-	msg := ethereum.CallMsg{
-		To:   &token,
-		Data: callData,
-	}
-	output, err := client.CallContract(ctx, msg, nil)
-	if err != nil {
-		return 0, merrors.Internal("decimals call failed: " + err.Error())
-	}
-	values, err := tokenABI.Unpack("decimals", output)
-	if err != nil {
-		return 0, merrors.Internal("failed to unpack decimals: " + err.Error())
-	}
-	if len(values) == 0 {
-		return 0, merrors.Internal("decimals call returned no data")
-	}
-	decimals, ok := values[0].(uint8)
-	if !ok {
-		return 0, merrors.Internal("decimals call returned unexpected type")
-	}
-	return decimals, nil
-}
-
-func toBaseUnits(amount string, decimals uint8) (*big.Int, error) {
-	value, err := decimal.NewFromString(strings.TrimSpace(amount))
-	if err != nil {
-		return nil, merrors.InvalidArgument("invalid amount " + amount + ": " + err.Error())
-	}
-	if value.IsNegative() {
-		return nil, merrors.InvalidArgument("amount must be positive")
-	}
-	multiplier := decimal.NewFromInt(1).Shift(int32(decimals))
-	scaled := value.Mul(multiplier)
-	if !scaled.Equal(scaled.Truncate(0)) {
-		return nil, merrors.InvalidArgument("amount " + amount + " exceeds token precision")
-	}
-	return scaled.BigInt(), nil
-}
-
-const erc20TransferABI = `
-[
-	{
-		"constant": true,
-		"inputs": [],
-		"name": "decimals",
-		"outputs": [{ "name": "", "type": "uint8" }],
-		"payable": false,
-		"stateMutability": "view",
-        "type": "function"
-	},
-	{
-		"constant": false,
-		"inputs": [
-			{ "name": "_to", "type": "address" },
-			{ "name": "_value", "type": "uint256" }
-		],
-		"name": "transfer",
-		"outputs": [{ "name": "", "type": "bool" }],
-		"payable": false,
-		"stateMutability": "nonpayable",
-		"type": "function"
-	}
-]`

api/gateway/chain/internal/service/gateway/commands/transfer/gas_topup.go

@@ -0,0 +1,290 @@
+package transfer
+
+import (
+	"context"
+	"strings"
+
+	"github.com/shopspring/decimal"
+	"github.com/tech/sendico/gateway/chain/internal/service/gateway/commands/wallet"
+	"github.com/tech/sendico/gateway/chain/internal/service/gateway/driver/evm"
+	"github.com/tech/sendico/gateway/chain/internal/service/gateway/driver/tron"
+	"github.com/tech/sendico/gateway/chain/internal/service/gateway/shared"
+	"github.com/tech/sendico/gateway/chain/storage/model"
+	"github.com/tech/sendico/pkg/api/routers/gsresponse"
+	"github.com/tech/sendico/pkg/merrors"
+	"github.com/tech/sendico/pkg/mlogger"
+	"github.com/tech/sendico/pkg/mservice"
+	moneyv1 "github.com/tech/sendico/pkg/proto/common/money/v1"
+	chainv1 "github.com/tech/sendico/pkg/proto/gateway/chain/v1"
+	"go.uber.org/zap"
+)
+
+type computeGasTopUpCommand struct {
+	deps Deps
+}
+
+func NewComputeGasTopUp(deps Deps) *computeGasTopUpCommand {
+	return &computeGasTopUpCommand{deps: deps}
+}
+
+func (c *computeGasTopUpCommand) Execute(ctx context.Context, req *chainv1.ComputeGasTopUpRequest) gsresponse.Responder[chainv1.ComputeGasTopUpResponse] {
+	if err := c.deps.EnsureRepository(ctx); err != nil {
+		c.deps.Logger.Warn("repository unavailable", zap.Error(err))
+		return gsresponse.Unavailable[chainv1.ComputeGasTopUpResponse](c.deps.Logger, mservice.ChainGateway, err)
+	}
+	if req == nil {
+		c.deps.Logger.Warn("nil request")
+		return gsresponse.InvalidArgument[chainv1.ComputeGasTopUpResponse](c.deps.Logger, mservice.ChainGateway, merrors.InvalidArgument("request is required"))
+	}
+
+	walletRef := strings.TrimSpace(req.GetWalletRef())
+	if walletRef == "" {
+		c.deps.Logger.Warn("wallet ref missing")
+		return gsresponse.InvalidArgument[chainv1.ComputeGasTopUpResponse](c.deps.Logger, mservice.ChainGateway, merrors.InvalidArgument("wallet_ref is required"))
+	}
+	estimatedFee := req.GetEstimatedTotalFee()
+	if estimatedFee == nil || strings.TrimSpace(estimatedFee.GetAmount()) == "" || strings.TrimSpace(estimatedFee.GetCurrency()) == "" {
+		c.deps.Logger.Warn("estimated fee missing")
+		return gsresponse.InvalidArgument[chainv1.ComputeGasTopUpResponse](c.deps.Logger, mservice.ChainGateway, merrors.InvalidArgument("estimated_total_fee is required"))
+	}
+
+	topUp, capHit, decision, nativeBalance, walletModel, err := computeGasTopUp(ctx, c.deps, walletRef, estimatedFee)
+	if err != nil {
+		return gsresponse.Auto[chainv1.ComputeGasTopUpResponse](c.deps.Logger, mservice.ChainGateway, err)
+	}
+
+	logDecision(c.deps.Logger, walletRef, estimatedFee, nativeBalance, topUp, capHit, decision, walletModel)
+
+	return gsresponse.Success(&chainv1.ComputeGasTopUpResponse{
+		TopupAmount: topUp,
+		CapHit:      capHit,
+	})
+}
+
+type ensureGasTopUpCommand struct {
+	deps Deps
+}
+
+func NewEnsureGasTopUp(deps Deps) *ensureGasTopUpCommand {
+	return &ensureGasTopUpCommand{deps: deps}
+}
+
+func (c *ensureGasTopUpCommand) Execute(ctx context.Context, req *chainv1.EnsureGasTopUpRequest) gsresponse.Responder[chainv1.EnsureGasTopUpResponse] {
+	if err := c.deps.EnsureRepository(ctx); err != nil {
+		c.deps.Logger.Warn("repository unavailable", zap.Error(err))
+		return gsresponse.Unavailable[chainv1.EnsureGasTopUpResponse](c.deps.Logger, mservice.ChainGateway, err)
+	}
+	if req == nil {
+		c.deps.Logger.Warn("nil request")
+		return gsresponse.InvalidArgument[chainv1.EnsureGasTopUpResponse](c.deps.Logger, mservice.ChainGateway, merrors.InvalidArgument("request is required"))
+	}
+
+	idempotencyKey := strings.TrimSpace(req.GetIdempotencyKey())
+	if idempotencyKey == "" {
+		c.deps.Logger.Warn("idempotency key missing")
+		return gsresponse.InvalidArgument[chainv1.EnsureGasTopUpResponse](c.deps.Logger, mservice.ChainGateway, merrors.InvalidArgument("idempotency_key is required"))
+	}
+	organizationRef := strings.TrimSpace(req.GetOrganizationRef())
+	if organizationRef == "" {
+		c.deps.Logger.Warn("organization ref missing")
+		return gsresponse.InvalidArgument[chainv1.EnsureGasTopUpResponse](c.deps.Logger, mservice.ChainGateway, merrors.InvalidArgument("organization_ref is required"))
+	}
+	sourceWalletRef := strings.TrimSpace(req.GetSourceWalletRef())
+	if sourceWalletRef == "" {
+		c.deps.Logger.Warn("source wallet ref missing")
+		return gsresponse.InvalidArgument[chainv1.EnsureGasTopUpResponse](c.deps.Logger, mservice.ChainGateway, merrors.InvalidArgument("source_wallet_ref is required"))
+	}
+	targetWalletRef := strings.TrimSpace(req.GetTargetWalletRef())
+	if targetWalletRef == "" {
+		c.deps.Logger.Warn("target wallet ref missing")
+		return gsresponse.InvalidArgument[chainv1.EnsureGasTopUpResponse](c.deps.Logger, mservice.ChainGateway, merrors.InvalidArgument("target_wallet_ref is required"))
+	}
+	estimatedFee := req.GetEstimatedTotalFee()
+	if estimatedFee == nil || strings.TrimSpace(estimatedFee.GetAmount()) == "" || strings.TrimSpace(estimatedFee.GetCurrency()) == "" {
+		c.deps.Logger.Warn("estimated fee missing")
+		return gsresponse.InvalidArgument[chainv1.EnsureGasTopUpResponse](c.deps.Logger, mservice.ChainGateway, merrors.InvalidArgument("estimated_total_fee is required"))
+	}
+
+	topUp, capHit, decision, nativeBalance, walletModel, err := computeGasTopUp(ctx, c.deps, targetWalletRef, estimatedFee)
+	if err != nil {
+		return gsresponse.Auto[chainv1.EnsureGasTopUpResponse](c.deps.Logger, mservice.ChainGateway, err)
+	}
+
+	logDecision(c.deps.Logger, targetWalletRef, estimatedFee, nativeBalance, topUp, capHit, decision, walletModel)
+
+	if topUp == nil || strings.TrimSpace(topUp.GetAmount()) == "" {
+		return gsresponse.Success(&chainv1.EnsureGasTopUpResponse{
+			TopupAmount: nil,
+			CapHit:      capHit,
+		})
+	}
+
+	submitReq := &chainv1.SubmitTransferRequest{
+		IdempotencyKey:  idempotencyKey,
+		OrganizationRef: organizationRef,
+		SourceWalletRef: sourceWalletRef,
+		Destination: &chainv1.TransferDestination{
+			Destination: &chainv1.TransferDestination_ManagedWalletRef{ManagedWalletRef: targetWalletRef},
+		},
+		Amount:          topUp,
+		Metadata:        shared.CloneMetadata(req.GetMetadata()),
+		ClientReference: strings.TrimSpace(req.GetClientReference()),
+	}
+
+	submitResponder := NewSubmitTransfer(c.deps.WithLogger("transfer.submit")).Execute(ctx, submitReq)
+	return func(ctx context.Context) (*chainv1.EnsureGasTopUpResponse, error) {
+		submitResp, err := submitResponder(ctx)
+		if err != nil {
+			return nil, err
+		}
+		return &chainv1.EnsureGasTopUpResponse{
+			TopupAmount: topUp,
+			CapHit:      capHit,
+			Transfer:    submitResp.GetTransfer(),
+		}, nil
+	}
+}
+
+func computeGasTopUp(ctx context.Context, deps Deps, walletRef string, estimatedFee *moneyv1.Money) (*moneyv1.Money, bool, *tron.GasTopUpDecision, *moneyv1.Money, *model.ManagedWallet, error) {
+	walletRef = strings.TrimSpace(walletRef)
+	estimatedFee = shared.CloneMoney(estimatedFee)
+	walletModel, err := deps.Storage.Wallets().Get(ctx, walletRef)
+	if err != nil {
+		return nil, false, nil, nil, nil, err
+	}
+
+	networkKey := strings.ToLower(strings.TrimSpace(walletModel.Network))
+	networkCfg, ok := deps.Networks.Network(networkKey)
+	if !ok {
+		return nil, false, nil, nil, nil, merrors.InvalidArgument("unsupported chain for wallet")
+	}
+
+	nativeBalance, err := nativeBalanceForWallet(ctx, deps, walletModel)
+	if err != nil {
+		return nil, false, nil, nil, nil, err
+	}
+
+	if strings.HasPrefix(networkKey, "tron") {
+		topUp, decision, err := tron.ComputeGasTopUp(networkCfg, walletModel, estimatedFee, nativeBalance)
+		if err != nil {
+			return nil, false, nil, nil, nil, err
+		}
+		return topUp, decision.CapHit, &decision, nativeBalance, walletModel, nil
+	}
+
+	if networkCfg.GasTopUpPolicy != nil {
+		topUp, capHit, err := evm.ComputeGasTopUp(networkCfg, walletModel, estimatedFee, nativeBalance)
+		if err != nil {
+			return nil, false, nil, nil, nil, err
+		}
+		return topUp, capHit, nil, nativeBalance, walletModel, nil
+	}
+
+	topUp, err := defaultGasTopUp(estimatedFee, nativeBalance)
+	if err != nil {
+		return nil, false, nil, nil, nil, err
+	}
+	return topUp, false, nil, nativeBalance, walletModel, nil
+}
+
+func nativeBalanceForWallet(ctx context.Context, deps Deps, walletModel *model.ManagedWallet) (*moneyv1.Money, error) {
+	if walletModel == nil {
+		return nil, merrors.InvalidArgument("wallet is required")
+	}
+	walletDeps := wallet.Deps{
+		Logger:           deps.Logger.Named("wallet"),
+		Drivers:          deps.Drivers,
+		Networks:         deps.Networks,
+		KeyManager:       nil,
+		Storage:          deps.Storage,
+		Clock:            deps.Clock,
+		BalanceCacheTTL:  0,
+		RPCTimeout:       deps.RPCTimeout,
+		EnsureRepository: deps.EnsureRepository,
+	}
+	_, nativeBalance, err := wallet.OnChainWalletBalances(ctx, walletDeps, walletModel)
+	if err != nil {
+		return nil, err
+	}
+	if nativeBalance == nil || strings.TrimSpace(nativeBalance.GetAmount()) == "" || strings.TrimSpace(nativeBalance.GetCurrency()) == "" {
+		return nil, merrors.InvalidArgument("native balance is unavailable")
+	}
+	return nativeBalance, nil
+}
+
+func defaultGasTopUp(estimatedFee *moneyv1.Money, currentBalance *moneyv1.Money) (*moneyv1.Money, error) {
+	if estimatedFee == nil || strings.TrimSpace(estimatedFee.GetAmount()) == "" || strings.TrimSpace(estimatedFee.GetCurrency()) == "" {
+		return nil, merrors.InvalidArgument("estimated fee is required")
+	}
+	if currentBalance == nil || strings.TrimSpace(currentBalance.GetAmount()) == "" || strings.TrimSpace(currentBalance.GetCurrency()) == "" {
+		return nil, merrors.InvalidArgument("native balance is required")
+	}
+	if !strings.EqualFold(estimatedFee.GetCurrency(), currentBalance.GetCurrency()) {
+		return nil, merrors.InvalidArgument("native balance currency mismatch")
+	}
+
+	estimated, err := decimal.NewFromString(strings.TrimSpace(estimatedFee.GetAmount()))
+	if err != nil {
+		return nil, err
+	}
+	current, err := decimal.NewFromString(strings.TrimSpace(currentBalance.GetAmount()))
+	if err != nil {
+		return nil, err
+	}
+	required := estimated.Sub(current)
+	if !required.IsPositive() {
+		return nil, nil
+	}
+	return &moneyv1.Money{
+		Currency: strings.ToUpper(strings.TrimSpace(estimatedFee.GetCurrency())),
+		Amount:   required.String(),
+	}, nil
+}
+
+func logDecision(logger mlogger.Logger, walletRef string, estimatedFee *moneyv1.Money, nativeBalance *moneyv1.Money, topUp *moneyv1.Money, capHit bool, decision *tron.GasTopUpDecision, walletModel *model.ManagedWallet) {
+	if logger == nil {
+		return
+	}
+	fields := []zap.Field{
+		zap.String("wallet_ref", walletRef),
+		zap.String("estimated_total_fee", amountString(estimatedFee)),
+		zap.String("current_native_balance", amountString(nativeBalance)),
+		zap.String("topup_amount", amountString(topUp)),
+		zap.Bool("cap_hit", capHit),
+	}
+	if walletModel != nil {
+		fields = append(fields, zap.String("network", strings.TrimSpace(walletModel.Network)))
+	}
+	if decision != nil {
+		fields = append(fields,
+			zap.String("estimated_total_fee_trx", decision.EstimatedFeeTRX.String()),
+			zap.String("current_native_balance_trx", decision.CurrentBalanceTRX.String()),
+			zap.String("required_trx", decision.RequiredTRX.String()),
+			zap.String("buffered_required_trx", decision.BufferedRequiredTRX.String()),
+			zap.String("min_balance_topup_trx", decision.MinBalanceTopUpTRX.String()),
+			zap.String("raw_topup_trx", decision.RawTopUpTRX.String()),
+			zap.String("rounded_topup_trx", decision.RoundedTopUpTRX.String()),
+			zap.String("topup_trx", decision.TopUpTRX.String()),
+			zap.String("operation_type", decision.OperationType),
+		)
+	}
+	logger.Info("gas top-up decision", fields...)
+}
+
+func amountString(m *moneyv1.Money) string {
+	if m == nil {
+		return ""
+	}
+	amount := strings.TrimSpace(m.GetAmount())
+	currency := strings.TrimSpace(m.GetCurrency())
+	if amount == "" && currency == "" {
+		return ""
+	}
+	if currency == "" {
+		return amount
+	}
+	if amount == "" {
+		return currency
+	}
+	return amount + " " + currency
+}

api/gateway/chain/internal/service/gateway/commands/transfer/submit.go

@@ -78,7 +78,7 @@ func (c *submitTransferCommand) Execute(ctx context.Context, req *chainv1.Submit
 		return gsresponse.InvalidArgument[chainv1.SubmitTransferResponse](c.deps.Logger, mservice.ChainGateway, merrors.InvalidArgument("organization_ref mismatch with wallet"))
 	}
 	networkKey := strings.ToLower(strings.TrimSpace(sourceWallet.Network))
-	networkCfg, ok := c.deps.Networks[networkKey]
+	networkCfg, ok := c.deps.Networks.Network(networkKey)
 	if !ok {
 		c.deps.Logger.Warn("unsupported chain", zap.String("network", networkKey))
 		return gsresponse.InvalidArgument[chainv1.SubmitTransferResponse](c.deps.Logger, mservice.ChainGateway, merrors.InvalidArgument("unsupported chain for wallet"))

api/gateway/chain/internal/service/gateway/commands/wallet/balance.go

@@ -51,7 +51,7 @@ func (c *getWalletBalanceCommand) Execute(ctx context.Context, req *chainv1.GetW
 		return gsresponse.Auto[chainv1.GetWalletBalanceResponse](c.deps.Logger, mservice.ChainGateway, err)
 	}
 
-	balance, chainErr := onChainWalletBalance(ctx, c.deps, wallet)
+	tokenBalance, nativeBalance, chainErr := OnChainWalletBalances(ctx, c.deps, wallet)
 	if chainErr != nil {
 		c.deps.Logger.Warn("on-chain balance fetch failed, attempting cached balance", zap.Error(chainErr), zap.String("wallet_ref", walletRef))
 		stored, err := c.deps.Storage.Wallets().GetBalance(ctx, walletRef)
@@ -74,37 +74,47 @@ func (c *getWalletBalanceCommand) Execute(ctx context.Context, req *chainv1.GetW
 	}
 
 	calculatedAt := c.now()
-	c.persistCachedBalance(ctx, walletRef, balance, calculatedAt)
+	c.persistCachedBalance(ctx, walletRef, tokenBalance, nativeBalance, calculatedAt)
 
 	return gsresponse.Success(&chainv1.GetWalletBalanceResponse{
-		Balance: onChainBalanceToProto(balance, calculatedAt),
+		Balance: onChainBalanceToProto(tokenBalance, nativeBalance, calculatedAt),
 	})
 }
 
-func onChainBalanceToProto(balance *moneyv1.Money, calculatedAt time.Time) *chainv1.WalletBalance {
-	if balance == nil {
+func onChainBalanceToProto(balance *moneyv1.Money, native *moneyv1.Money, calculatedAt time.Time) *chainv1.WalletBalance {
+	if balance == nil && native == nil {
 		return nil
 	}
-	zero := zeroMoney(balance.Currency)
+	currency := ""
+	if balance != nil {
+		currency = balance.Currency
+	}
+	zero := zeroMoney(currency)
 	return &chainv1.WalletBalance{
 		Available:       balance,
+		NativeAvailable: native,
 		PendingInbound:  zero,
 		PendingOutbound: zero,
 		CalculatedAt:    timestamppb.New(calculatedAt.UTC()),
 	}
 }
 
-func (c *getWalletBalanceCommand) persistCachedBalance(ctx context.Context, walletRef string, available *moneyv1.Money, calculatedAt time.Time) {
-	if available == nil {
+func (c *getWalletBalanceCommand) persistCachedBalance(ctx context.Context, walletRef string, available *moneyv1.Money, nativeAvailable *moneyv1.Money, calculatedAt time.Time) {
+	if available == nil && nativeAvailable == nil {
 		return
 	}
 	record := &model.WalletBalance{
 		WalletRef:       walletRef,
 		Available:       shared.CloneMoney(available),
-		PendingInbound:  zeroMoney(available.Currency),
-		PendingOutbound: zeroMoney(available.Currency),
+		NativeAvailable: shared.CloneMoney(nativeAvailable),
 		CalculatedAt:    calculatedAt,
 	}
+	currency := ""
+	if available != nil {
+		currency = available.Currency
+	}
+	record.PendingInbound = zeroMoney(currency)
+	record.PendingOutbound = zeroMoney(currency)
 	if err := c.deps.Storage.Wallets().SaveBalance(ctx, record); err != nil {
 		c.deps.Logger.Warn("failed to cache wallet balance", zap.String("wallet_ref", walletRef), zap.Error(err))
 	}

api/gateway/chain/internal/service/gateway/commands/wallet/create.go

@@ -9,6 +9,7 @@ import (
 	"github.com/tech/sendico/gateway/chain/storage/model"
 	"github.com/tech/sendico/pkg/api/routers/gsresponse"
 	"github.com/tech/sendico/pkg/merrors"
+	pkgmodel "github.com/tech/sendico/pkg/model"
 	"github.com/tech/sendico/pkg/mservice"
 	chainv1 "github.com/tech/sendico/pkg/proto/gateway/chain/v1"
 	"go.uber.org/zap"
@@ -59,11 +60,20 @@ func (c *createManagedWalletCommand) Execute(ctx context.Context, req *chainv1.C
 		c.deps.Logger.Warn("unsupported chain", zap.Any("chain", asset.GetChain()))
 		return gsresponse.InvalidArgument[chainv1.CreateManagedWalletResponse](c.deps.Logger, mservice.ChainGateway, merrors.InvalidArgument("unsupported chain"))
 	}
-	networkCfg, ok := c.deps.Networks[chainKey]
+	networkCfg, ok := c.deps.Networks.Network(chainKey)
 	if !ok {
 		c.deps.Logger.Warn("unsupported chain in config", zap.String("chain", chainKey))
 		return gsresponse.InvalidArgument[chainv1.CreateManagedWalletResponse](c.deps.Logger, mservice.ChainGateway, merrors.InvalidArgument("unsupported chain"))
 	}
+	if c.deps.Drivers == nil {
+		c.deps.Logger.Warn("chain drivers missing", zap.String("chain", chainKey))
+		return gsresponse.Internal[chainv1.CreateManagedWalletResponse](c.deps.Logger, mservice.ChainGateway, merrors.Internal("chain drivers not configured"))
+	}
+	chainDriver, err := c.deps.Drivers.Driver(chainKey)
+	if err != nil {
+		c.deps.Logger.Warn("unsupported chain driver", zap.String("chain", chainKey), zap.Error(err))
+		return gsresponse.InvalidArgument[chainv1.CreateManagedWalletResponse](c.deps.Logger, mservice.ChainGateway, merrors.InvalidArgument("unsupported chain"))
+	}
 
 	tokenSymbol := strings.ToUpper(strings.TrimSpace(asset.GetTokenSymbol()))
 	if tokenSymbol == "" {
@@ -72,10 +82,12 @@ func (c *createManagedWalletCommand) Execute(ctx context.Context, req *chainv1.C
 	}
 	contractAddress := strings.ToLower(strings.TrimSpace(asset.GetContractAddress()))
 	if contractAddress == "" {
-		contractAddress = shared.ResolveContractAddress(networkCfg.TokenConfigs, tokenSymbol)
-		if contractAddress == "" {
-			c.deps.Logger.Warn("unsupported token", zap.String("token", tokenSymbol), zap.String("chain", chainKey))
-			return gsresponse.InvalidArgument[chainv1.CreateManagedWalletResponse](c.deps.Logger, mservice.ChainGateway, merrors.InvalidArgument("unsupported token for chain"))
+		if !strings.EqualFold(tokenSymbol, networkCfg.NativeToken) {
+			contractAddress = shared.ResolveContractAddress(networkCfg.TokenConfigs, tokenSymbol)
+			if contractAddress == "" {
+				c.deps.Logger.Warn("unsupported token", zap.String("token", tokenSymbol), zap.String("chain", chainKey))
+				return gsresponse.InvalidArgument[chainv1.CreateManagedWalletResponse](c.deps.Logger, mservice.ChainGateway, merrors.InvalidArgument("unsupported token for chain"))
+			}
 		}
 	}
 
@@ -94,8 +106,37 @@ func (c *createManagedWalletCommand) Execute(ctx context.Context, req *chainv1.C
 		c.deps.Logger.Warn("key manager returned empty address")
 		return gsresponse.Internal[chainv1.CreateManagedWalletResponse](c.deps.Logger, mservice.ChainGateway, merrors.Internal("key manager returned empty address"))
 	}
+	depositAddress, err := chainDriver.FormatAddress(keyInfo.Address)
+	if err != nil {
+		c.deps.Logger.Warn("invalid derived deposit address", zap.String("wallet_ref", walletRef), zap.Error(err))
+		return gsresponse.InvalidArgument[chainv1.CreateManagedWalletResponse](c.deps.Logger, mservice.ChainGateway, err)
+	}
+
+	metadata := shared.CloneMetadata(req.GetMetadata())
+	desc := req.GetDescribable()
+	name := strings.TrimSpace(desc.GetName())
+	if name == "" {
+		name = strings.TrimSpace(metadata["name"])
+	}
+	var description *string
+	if desc != nil && desc.Description != nil {
+		if trimmed := strings.TrimSpace(desc.GetDescription()); trimmed != "" {
+			description = &trimmed
+		}
+	}
+	if description == nil {
+		if trimmed := strings.TrimSpace(metadata["description"]); trimmed != "" {
+			description = &trimmed
+		}
+	}
+	if name == "" {
+		name = walletRef
+	}
 
 	wallet := &model.ManagedWallet{
+		Describable: pkgmodel.Describable{
+			Name: name,
+		},
 		IdempotencyKey:  idempotencyKey,
 		WalletRef:       walletRef,
 		OrganizationRef: organizationRef,
@@ -103,10 +144,13 @@ func (c *createManagedWalletCommand) Execute(ctx context.Context, req *chainv1.C
 		Network:         chainKey,
 		TokenSymbol:     tokenSymbol,
 		ContractAddress: contractAddress,
-		DepositAddress:  strings.ToLower(keyInfo.Address),
+		DepositAddress:  depositAddress,
 		KeyReference:    keyInfo.KeyID,
 		Status:          model.ManagedWalletStatusActive,
-		Metadata:        shared.CloneMetadata(req.GetMetadata()),
+		Metadata:        metadata,
+	}
+	if description != nil {
+		wallet.Describable.Description = description
 	}
 
 	created, err := c.deps.Storage.Wallets().Create(ctx, wallet)

api/gateway/chain/internal/service/gateway/commands/wallet/deps.go

@@ -5,7 +5,8 @@ import (
 	"time"
 
 	"github.com/tech/sendico/gateway/chain/internal/keymanager"
-	"github.com/tech/sendico/gateway/chain/internal/service/gateway/shared"
+	"github.com/tech/sendico/gateway/chain/internal/service/gateway/drivers"
+	"github.com/tech/sendico/gateway/chain/internal/service/gateway/rpcclient"
 	"github.com/tech/sendico/gateway/chain/storage"
 	clockpkg "github.com/tech/sendico/pkg/clock"
 	"github.com/tech/sendico/pkg/mlogger"
@@ -13,17 +14,20 @@ import (
 
 type Deps struct {
 	Logger           mlogger.Logger
-	Networks         map[string]shared.Network
+	Drivers          *drivers.Registry
+	Networks         *rpcclient.Registry
 	KeyManager       keymanager.Manager
 	Storage          storage.Repository
 	Clock            clockpkg.Clock
 	BalanceCacheTTL  time.Duration
+	RPCTimeout       time.Duration
 	EnsureRepository func(context.Context) error
 }
 
 func (d Deps) WithLogger(name string) Deps {
-	if d.Logger != nil {
-		d.Logger = d.Logger.Named(name)
+	if d.Logger == nil {
+		panic("wallet deps: logger is required")
 	}
+	d.Logger = d.Logger.Named(name)
 	return d
 }

api/gateway/chain/internal/service/gateway/commands/wallet/onchain_balance.go

@@ -2,123 +2,61 @@ package wallet
 
 import (
 	"context"
-	"math/big"
+	"fmt"
 	"strings"
-	"time"
 
-	"github.com/ethereum/go-ethereum"
-	"github.com/ethereum/go-ethereum/accounts/abi"
-	"github.com/ethereum/go-ethereum/common"
-	"github.com/ethereum/go-ethereum/ethclient"
-	"github.com/shopspring/decimal"
+	"github.com/tech/sendico/gateway/chain/internal/service/gateway/driver"
 	"github.com/tech/sendico/gateway/chain/storage/model"
 	"github.com/tech/sendico/pkg/merrors"
 	moneyv1 "github.com/tech/sendico/pkg/proto/common/money/v1"
+	"go.uber.org/zap"
 )
 
-func onChainWalletBalance(ctx context.Context, deps Deps, wallet *model.ManagedWallet) (*moneyv1.Money, error) {
-	network := deps.Networks[strings.ToLower(strings.TrimSpace(wallet.Network))]
-	rpcURL := strings.TrimSpace(network.RPCURL)
-	if rpcURL == "" {
-		return nil, merrors.Internal("network rpc url is not configured")
+func OnChainWalletBalances(ctx context.Context, deps Deps, wallet *model.ManagedWallet) (*moneyv1.Money, *moneyv1.Money, error) {
+	logger := deps.Logger
+	if wallet == nil {
+		return nil, nil, merrors.InvalidArgument("wallet is required")
 	}
-	contract := strings.TrimSpace(wallet.ContractAddress)
-	if contract == "" || !common.IsHexAddress(contract) {
-		return nil, merrors.InvalidArgument("invalid contract address")
+	if deps.Networks == nil {
+		return nil, nil, merrors.Internal("rpc clients not initialised")
 	}
-	if wallet.DepositAddress == "" || !common.IsHexAddress(wallet.DepositAddress) {
-		return nil, merrors.InvalidArgument("invalid wallet address")
+	if deps.Drivers == nil {
+		return nil, nil, merrors.Internal("chain drivers not configured")
 	}
 
-	client, err := ethclient.DialContext(ctx, rpcURL)
-	if err != nil {
-		return nil, merrors.Internal("failed to connect rpc: " + err.Error())
-	}
-	defer client.Close()
-
-	timeoutCtx, cancel := context.WithTimeout(ctx, 10*time.Second)
-	defer cancel()
-
-	tokenABI, err := abi.JSON(strings.NewReader(erc20ABIJSON))
-	if err != nil {
-		return nil, merrors.Internal("failed to parse erc20 abi: " + err.Error())
-	}
-	tokenAddr := common.HexToAddress(contract)
-	walletAddr := common.HexToAddress(wallet.DepositAddress)
-
-	decimals, err := readDecimals(timeoutCtx, client, tokenABI, tokenAddr)
-	if err != nil {
-		return nil, err
-	}
-
-	bal, err := readBalanceOf(timeoutCtx, client, tokenABI, tokenAddr, walletAddr)
-	if err != nil {
-		return nil, err
-	}
-
-	dec := decimal.NewFromBigInt(bal, 0).Shift(-int32(decimals))
-	return &moneyv1.Money{Currency: wallet.TokenSymbol, Amount: dec.String()}, nil
-}
-
-func readDecimals(ctx context.Context, client *ethclient.Client, tokenABI abi.ABI, token common.Address) (uint8, error) {
-	data, err := tokenABI.Pack("decimals")
-	if err != nil {
-		return 0, merrors.Internal("failed to encode decimals call: " + err.Error())
-	}
-	msg := ethereum.CallMsg{To: &token, Data: data}
-	out, err := client.CallContract(ctx, msg, nil)
-	if err != nil {
-		return 0, merrors.Internal("decimals call failed: " + err.Error())
-	}
-	values, err := tokenABI.Unpack("decimals", out)
-	if err != nil || len(values) == 0 {
-		return 0, merrors.Internal("failed to unpack decimals")
-	}
-	if val, ok := values[0].(uint8); ok {
-		return val, nil
-	}
-	return 0, merrors.Internal("decimals returned unexpected type")
-}
-
-func readBalanceOf(ctx context.Context, client *ethclient.Client, tokenABI abi.ABI, token common.Address, wallet common.Address) (*big.Int, error) {
-	data, err := tokenABI.Pack("balanceOf", wallet)
-	if err != nil {
-		return nil, merrors.Internal("failed to encode balanceOf: " + err.Error())
-	}
-	msg := ethereum.CallMsg{To: &token, Data: data}
-	out, err := client.CallContract(ctx, msg, nil)
-	if err != nil {
-		return nil, merrors.Internal("balanceOf call failed: " + err.Error())
-	}
-	values, err := tokenABI.Unpack("balanceOf", out)
-	if err != nil || len(values) == 0 {
-		return nil, merrors.Internal("failed to unpack balanceOf")
-	}
-	raw, ok := values[0].(*big.Int)
+	networkKey := strings.ToLower(strings.TrimSpace(wallet.Network))
+	network, ok := deps.Networks.Network(networkKey)
 	if !ok {
-		return nil, merrors.Internal("balanceOf returned unexpected type")
+		logger.Warn("Requested network is not configured",
+			zap.String("wallet_ref", wallet.WalletRef),
+			zap.String("network", networkKey),
+		)
+		return nil, nil, merrors.Internal(fmt.Sprintf("Requested network '%s' is not configured", networkKey))
 	}
-	return decimal.NewFromBigInt(raw, 0).BigInt(), nil
-}
 
-const erc20ABIJSON = `
-[
-	{
-		"constant": true,
-		"inputs": [],
-		"name": "decimals",
-		"outputs": [{ "name": "", "type": "uint8" }],
-		"payable": false,
-		"stateMutability": "view",
-        "type": "function"
-	},
-	{
-		"constant": true,
-		"inputs": [{ "name": "_owner", "type": "address" }],
-		"name": "balanceOf",
-		"outputs": [{ "name": "balance", "type": "uint256" }],
-		"payable": false,
-		"stateMutability": "view",
-		"type": "function"
+	chainDriver, err := deps.Drivers.Driver(networkKey)
+	if err != nil {
+		logger.Warn("Chain driver not configured",
+			zap.String("wallet_ref", wallet.WalletRef),
+			zap.String("network", networkKey),
+			zap.Error(err),
+		)
+		return nil, nil, merrors.InvalidArgument("unsupported chain")
 	}
-]`
+
+	driverDeps := driver.Deps{
+		Logger:     deps.Logger,
+		Registry:   deps.Networks,
+		KeyManager: deps.KeyManager,
+		RPCTimeout: deps.RPCTimeout,
+	}
+	tokenBalance, err := chainDriver.Balance(ctx, driverDeps, network, wallet)
+	if err != nil {
+		return nil, nil, err
+	}
+	nativeBalance, err := chainDriver.NativeBalance(ctx, driverDeps, network, wallet)
+	if err != nil {
+		return nil, nil, err
+	}
+	return tokenBalance, nativeBalance, nil
+}

api/gateway/chain/internal/service/gateway/commands/wallet/proto.go

@@ -1,8 +1,11 @@
 package wallet
 
 import (
+	"strings"
+
 	"github.com/tech/sendico/gateway/chain/internal/service/gateway/shared"
 	"github.com/tech/sendico/gateway/chain/storage/model"
+	describablev1 "github.com/tech/sendico/pkg/proto/common/describable/v1"
 	chainv1 "github.com/tech/sendico/pkg/proto/gateway/chain/v1"
 	"google.golang.org/protobuf/types/known/timestamppb"
 )
@@ -16,6 +19,25 @@ func toProtoManagedWallet(wallet *model.ManagedWallet) *chainv1.ManagedWallet {
 		TokenSymbol:     wallet.TokenSymbol,
 		ContractAddress: wallet.ContractAddress,
 	}
+	name := strings.TrimSpace(wallet.Name)
+	if name == "" {
+		name = strings.TrimSpace(wallet.Metadata["name"])
+	}
+	if name == "" {
+		name = wallet.WalletRef
+	}
+	description := ""
+	switch {
+	case wallet.Description != nil:
+		description = strings.TrimSpace(*wallet.Description)
+	default:
+		description = strings.TrimSpace(wallet.Metadata["description"])
+	}
+	desc := &describablev1.Describable{Name: name}
+	if description != "" {
+		desc.Description = &description
+	}
+
 	return &chainv1.ManagedWallet{
 		WalletRef:       wallet.WalletRef,
 		OrganizationRef: wallet.OrganizationRef,
@@ -26,6 +48,7 @@ func toProtoManagedWallet(wallet *model.ManagedWallet) *chainv1.ManagedWallet {
 		Metadata:        shared.CloneMetadata(wallet.Metadata),
 		CreatedAt:       timestamppb.New(wallet.CreatedAt.UTC()),
 		UpdatedAt:       timestamppb.New(wallet.UpdatedAt.UTC()),
+		Describable:     desc,
 	}
 }
 
@@ -35,6 +58,7 @@ func toProtoWalletBalance(balance *model.WalletBalance) *chainv1.WalletBalance {
 	}
 	return &chainv1.WalletBalance{
 		Available:       shared.CloneMoney(balance.Available),
+		NativeAvailable: shared.CloneMoney(balance.NativeAvailable),
 		PendingInbound:  shared.CloneMoney(balance.PendingInbound),
 		PendingOutbound: shared.CloneMoney(balance.PendingOutbound),
 		CalculatedAt:    timestamppb.New(balance.CalculatedAt.UTC()),

api/gateway/chain/internal/service/gateway/driver/arbitrum/driver.go

@@ -0,0 +1,173 @@
+package arbitrum
+
+import (
+	"context"
+
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/tech/sendico/gateway/chain/internal/service/gateway/driver"
+	"github.com/tech/sendico/gateway/chain/internal/service/gateway/driver/evm"
+	"github.com/tech/sendico/gateway/chain/internal/service/gateway/shared"
+	"github.com/tech/sendico/gateway/chain/storage/model"
+	"github.com/tech/sendico/pkg/mlogger"
+	moneyv1 "github.com/tech/sendico/pkg/proto/common/money/v1"
+	"go.uber.org/zap"
+)
+
+// Driver implements Arbitrum-specific behavior using the shared EVM logic.
+type Driver struct {
+	logger mlogger.Logger
+}
+
+func New(logger mlogger.Logger) *Driver {
+	return &Driver{logger: logger.Named("arbitrum")}
+}
+
+func (d *Driver) Name() string {
+	return "arbitrum"
+}
+
+func (d *Driver) FormatAddress(address string) (string, error) {
+	d.logger.Debug("format address", zap.String("address", address))
+	normalized, err := evm.NormalizeAddress(address)
+	if err != nil {
+		d.logger.Warn("format address failed", zap.String("address", address), zap.Error(err))
+	}
+	return normalized, err
+}
+
+func (d *Driver) NormalizeAddress(address string) (string, error) {
+	d.logger.Debug("normalize address", zap.String("address", address))
+	normalized, err := evm.NormalizeAddress(address)
+	if err != nil {
+		d.logger.Warn("normalize address failed", zap.String("address", address), zap.Error(err))
+	}
+	return normalized, err
+}
+
+func (d *Driver) Balance(ctx context.Context, deps driver.Deps, network shared.Network, wallet *model.ManagedWallet) (*moneyv1.Money, error) {
+	d.logger.Debug("balance request",
+		zap.String("wallet_ref", wallet.WalletRef),
+		zap.String("network", network.Name),
+	)
+	driverDeps := deps
+	driverDeps.Logger = d.logger
+	result, err := evm.Balance(ctx, driverDeps, network, wallet, wallet.DepositAddress)
+	if err != nil {
+		d.logger.Warn("balance failed",
+			zap.String("wallet_ref", wallet.WalletRef),
+			zap.String("network", network.Name),
+			zap.Error(err),
+		)
+	} else if result != nil {
+		d.logger.Debug("balance result",
+			zap.String("wallet_ref", wallet.WalletRef),
+			zap.String("network", network.Name),
+			zap.String("amount", result.Amount),
+			zap.String("currency", result.Currency),
+		)
+	}
+	return result, err
+}
+
+func (d *Driver) NativeBalance(ctx context.Context, deps driver.Deps, network shared.Network, wallet *model.ManagedWallet) (*moneyv1.Money, error) {
+	d.logger.Debug("native balance request",
+		zap.String("wallet_ref", wallet.WalletRef),
+		zap.String("network", network.Name),
+	)
+	driverDeps := deps
+	driverDeps.Logger = d.logger
+	result, err := evm.NativeBalance(ctx, driverDeps, network, wallet, wallet.DepositAddress)
+	if err != nil {
+		d.logger.Warn("native balance failed",
+			zap.String("wallet_ref", wallet.WalletRef),
+			zap.String("network", network.Name),
+			zap.Error(err),
+		)
+	} else if result != nil {
+		d.logger.Debug("native balance result",
+			zap.String("wallet_ref", wallet.WalletRef),
+			zap.String("network", network.Name),
+			zap.String("amount", result.Amount),
+			zap.String("currency", result.Currency),
+		)
+	}
+	return result, err
+}
+
+func (d *Driver) EstimateFee(ctx context.Context, deps driver.Deps, network shared.Network, wallet *model.ManagedWallet, destination string, amount *moneyv1.Money) (*moneyv1.Money, error) {
+	d.logger.Debug("estimate fee request",
+		zap.String("wallet_ref", wallet.WalletRef),
+		zap.String("network", network.Name),
+		zap.String("destination", destination),
+	)
+	driverDeps := deps
+	driverDeps.Logger = d.logger
+	result, err := evm.EstimateFee(ctx, driverDeps, network, wallet, wallet.DepositAddress, destination, amount)
+	if err != nil {
+		d.logger.Warn("estimate fee failed",
+			zap.String("wallet_ref", wallet.WalletRef),
+			zap.String("network", network.Name),
+			zap.Error(err),
+		)
+	} else if result != nil {
+		d.logger.Debug("estimate fee result",
+			zap.String("wallet_ref", wallet.WalletRef),
+			zap.String("network", network.Name),
+			zap.String("amount", result.Amount),
+			zap.String("currency", result.Currency),
+		)
+	}
+	return result, err
+}
+
+func (d *Driver) SubmitTransfer(ctx context.Context, deps driver.Deps, network shared.Network, transfer *model.Transfer, source *model.ManagedWallet, destination string) (string, error) {
+	d.logger.Debug("submit transfer request",
+		zap.String("transfer_ref", transfer.TransferRef),
+		zap.String("network", network.Name),
+		zap.String("destination", destination),
+	)
+	driverDeps := deps
+	driverDeps.Logger = d.logger
+	txHash, err := evm.SubmitTransfer(ctx, driverDeps, network, transfer, source, source.DepositAddress, destination)
+	if err != nil {
+		d.logger.Warn("submit transfer failed",
+			zap.String("transfer_ref", transfer.TransferRef),
+			zap.String("network", network.Name),
+			zap.Error(err),
+		)
+	} else {
+		d.logger.Debug("submit transfer result",
+			zap.String("transfer_ref", transfer.TransferRef),
+			zap.String("network", network.Name),
+			zap.String("tx_hash", txHash),
+		)
+	}
+	return txHash, err
+}
+
+func (d *Driver) AwaitConfirmation(ctx context.Context, deps driver.Deps, network shared.Network, txHash string) (*types.Receipt, error) {
+	d.logger.Debug("await confirmation",
+		zap.String("tx_hash", txHash),
+		zap.String("network", network.Name),
+	)
+	driverDeps := deps
+	driverDeps.Logger = d.logger
+	receipt, err := evm.AwaitConfirmation(ctx, driverDeps, network, txHash)
+	if err != nil {
+		d.logger.Warn("await confirmation failed",
+			zap.String("tx_hash", txHash),
+			zap.String("network", network.Name),
+			zap.Error(err),
+		)
+	} else if receipt != nil {
+		d.logger.Debug("await confirmation result",
+			zap.String("tx_hash", txHash),
+			zap.String("network", network.Name),
+			zap.Uint64("block_number", receipt.BlockNumber.Uint64()),
+			zap.Uint64("status", receipt.Status),
+		)
+	}
+	return receipt, err
+}
+
+var _ driver.Driver = (*Driver)(nil)

api/gateway/chain/internal/service/gateway/driver/driver.go

@@ -0,0 +1,34 @@
+package driver
+
+import (
+	"context"
+	"time"
+
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/tech/sendico/gateway/chain/internal/keymanager"
+	"github.com/tech/sendico/gateway/chain/internal/service/gateway/rpcclient"
+	"github.com/tech/sendico/gateway/chain/internal/service/gateway/shared"
+	"github.com/tech/sendico/gateway/chain/storage/model"
+	"github.com/tech/sendico/pkg/mlogger"
+	moneyv1 "github.com/tech/sendico/pkg/proto/common/money/v1"
+)
+
+// Deps bundles dependencies shared across chain drivers.
+type Deps struct {
+	Logger     mlogger.Logger
+	Registry   *rpcclient.Registry
+	KeyManager keymanager.Manager
+	RPCTimeout time.Duration
+}
+
+// Driver defines chain-specific behavior for wallet and transfer operations.
+type Driver interface {
+	Name() string
+	FormatAddress(address string) (string, error)
+	NormalizeAddress(address string) (string, error)
+	Balance(ctx context.Context, deps Deps, network shared.Network, wallet *model.ManagedWallet) (*moneyv1.Money, error)
+	NativeBalance(ctx context.Context, deps Deps, network shared.Network, wallet *model.ManagedWallet) (*moneyv1.Money, error)
+	EstimateFee(ctx context.Context, deps Deps, network shared.Network, wallet *model.ManagedWallet, destination string, amount *moneyv1.Money) (*moneyv1.Money, error)
+	SubmitTransfer(ctx context.Context, deps Deps, network shared.Network, transfer *model.Transfer, source *model.ManagedWallet, destination string) (string, error)
+	AwaitConfirmation(ctx context.Context, deps Deps, network shared.Network, txHash string) (*types.Receipt, error)
+}

api/gateway/chain/internal/service/gateway/driver/ethereum/driver.go

@@ -0,0 +1,173 @@
+package ethereum
+
+import (
+	"context"
+
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/tech/sendico/gateway/chain/internal/service/gateway/driver"
+	"github.com/tech/sendico/gateway/chain/internal/service/gateway/driver/evm"
+	"github.com/tech/sendico/gateway/chain/internal/service/gateway/shared"
+	"github.com/tech/sendico/gateway/chain/storage/model"
+	"github.com/tech/sendico/pkg/mlogger"
+	moneyv1 "github.com/tech/sendico/pkg/proto/common/money/v1"
+	"go.uber.org/zap"
+)
+
+// Driver implements Ethereum-specific behavior using the shared EVM logic.
+type Driver struct {
+	logger mlogger.Logger
+}
+
+func New(logger mlogger.Logger) *Driver {
+	return &Driver{logger: logger.Named("ethereum")}
+}
+
+func (d *Driver) Name() string {
+	return "ethereum"
+}
+
+func (d *Driver) FormatAddress(address string) (string, error) {
+	d.logger.Debug("format address", zap.String("address", address))
+	normalized, err := evm.NormalizeAddress(address)
+	if err != nil {
+		d.logger.Warn("format address failed", zap.String("address", address), zap.Error(err))
+	}
+	return normalized, err
+}
+
+func (d *Driver) NormalizeAddress(address string) (string, error) {
+	d.logger.Debug("normalize address", zap.String("address", address))
+	normalized, err := evm.NormalizeAddress(address)
+	if err != nil {
+		d.logger.Warn("normalize address failed", zap.String("address", address), zap.Error(err))
+	}
+	return normalized, err
+}
+
+func (d *Driver) Balance(ctx context.Context, deps driver.Deps, network shared.Network, wallet *model.ManagedWallet) (*moneyv1.Money, error) {
+	d.logger.Debug("balance request",
+		zap.String("wallet_ref", wallet.WalletRef),
+		zap.String("network", network.Name),
+	)
+	driverDeps := deps
+	driverDeps.Logger = d.logger
+	result, err := evm.Balance(ctx, driverDeps, network, wallet, wallet.DepositAddress)
+	if err != nil {
+		d.logger.Warn("balance failed",
+			zap.String("wallet_ref", wallet.WalletRef),
+			zap.String("network", network.Name),
+			zap.Error(err),
+		)
+	} else if result != nil {
+		d.logger.Debug("balance result",
+			zap.String("wallet_ref", wallet.WalletRef),
+			zap.String("network", network.Name),
+			zap.String("amount", result.Amount),
+			zap.String("currency", result.Currency),
+		)
+	}
+	return result, err
+}
+
+func (d *Driver) NativeBalance(ctx context.Context, deps driver.Deps, network shared.Network, wallet *model.ManagedWallet) (*moneyv1.Money, error) {
+	d.logger.Debug("native balance request",
+		zap.String("wallet_ref", wallet.WalletRef),
+		zap.String("network", network.Name),
+	)
+	driverDeps := deps
+	driverDeps.Logger = d.logger
+	result, err := evm.NativeBalance(ctx, driverDeps, network, wallet, wallet.DepositAddress)
+	if err != nil {
+		d.logger.Warn("native balance failed",
+			zap.String("wallet_ref", wallet.WalletRef),
+			zap.String("network", network.Name),
+			zap.Error(err),
+		)
+	} else if result != nil {
+		d.logger.Debug("native balance result",
+			zap.String("wallet_ref", wallet.WalletRef),
+			zap.String("network", network.Name),
+			zap.String("amount", result.Amount),
+			zap.String("currency", result.Currency),
+		)
+	}
+	return result, err
+}
+
+func (d *Driver) EstimateFee(ctx context.Context, deps driver.Deps, network shared.Network, wallet *model.ManagedWallet, destination string, amount *moneyv1.Money) (*moneyv1.Money, error) {
+	d.logger.Debug("estimate fee request",
+		zap.String("wallet_ref", wallet.WalletRef),
+		zap.String("network", network.Name),
+		zap.String("destination", destination),
+	)
+	driverDeps := deps
+	driverDeps.Logger = d.logger
+	result, err := evm.EstimateFee(ctx, driverDeps, network, wallet, wallet.DepositAddress, destination, amount)
+	if err != nil {
+		d.logger.Warn("estimate fee failed",
+			zap.String("wallet_ref", wallet.WalletRef),
+			zap.String("network", network.Name),
+			zap.Error(err),
+		)
+	} else if result != nil {
+		d.logger.Debug("estimate fee result",
+			zap.String("wallet_ref", wallet.WalletRef),
+			zap.String("network", network.Name),
+			zap.String("amount", result.Amount),
+			zap.String("currency", result.Currency),
+		)
+	}
+	return result, err
+}
+
+func (d *Driver) SubmitTransfer(ctx context.Context, deps driver.Deps, network shared.Network, transfer *model.Transfer, source *model.ManagedWallet, destination string) (string, error) {
+	d.logger.Debug("submit transfer request",
+		zap.String("transfer_ref", transfer.TransferRef),
+		zap.String("network", network.Name),
+		zap.String("destination", destination),
+	)
+	driverDeps := deps
+	driverDeps.Logger = d.logger
+	txHash, err := evm.SubmitTransfer(ctx, driverDeps, network, transfer, source, source.DepositAddress, destination)
+	if err != nil {
+		d.logger.Warn("submit transfer failed",
+			zap.String("transfer_ref", transfer.TransferRef),
+			zap.String("network", network.Name),
+			zap.Error(err),
+		)
+	} else {
+		d.logger.Debug("submit transfer result",
+			zap.String("transfer_ref", transfer.TransferRef),
+			zap.String("network", network.Name),
+			zap.String("tx_hash", txHash),
+		)
+	}
+	return txHash, err
+}
+
+func (d *Driver) AwaitConfirmation(ctx context.Context, deps driver.Deps, network shared.Network, txHash string) (*types.Receipt, error) {
+	d.logger.Debug("await confirmation",
+		zap.String("tx_hash", txHash),
+		zap.String("network", network.Name),
+	)
+	driverDeps := deps
+	driverDeps.Logger = d.logger
+	receipt, err := evm.AwaitConfirmation(ctx, driverDeps, network, txHash)
+	if err != nil {
+		d.logger.Warn("await confirmation failed",
+			zap.String("tx_hash", txHash),
+			zap.String("network", network.Name),
+			zap.Error(err),
+		)
+	} else if receipt != nil {
+		d.logger.Debug("await confirmation result",
+			zap.String("tx_hash", txHash),
+			zap.String("network", network.Name),
+			zap.Uint64("block_number", receipt.BlockNumber.Uint64()),
+			zap.Uint64("status", receipt.Status),
+		)
+	}
+	return receipt, err
+}
+
+var _ driver.Driver = (*Driver)(nil)

api/gateway/chain/internal/service/gateway/driver/evm/evm.go

@@ -0,0 +1,680 @@
+package evm
+
+import (
+	"context"
+	"errors"
+	"math/big"
+	"strings"
+	"time"
+
+	"github.com/ethereum/go-ethereum"
+	"github.com/ethereum/go-ethereum/accounts/abi"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/rpc"
+	"github.com/shopspring/decimal"
+	"github.com/tech/sendico/gateway/chain/internal/service/gateway/driver"
+	"github.com/tech/sendico/gateway/chain/internal/service/gateway/shared"
+	"github.com/tech/sendico/gateway/chain/storage/model"
+	"github.com/tech/sendico/pkg/merrors"
+	moneyv1 "github.com/tech/sendico/pkg/proto/common/money/v1"
+	"go.uber.org/zap"
+)
+
+var (
+	erc20ABI abi.ABI
+)
+
+func init() {
+	var err error
+	erc20ABI, err = abi.JSON(strings.NewReader(erc20ABIJSON))
+	if err != nil {
+		panic("evm driver: failed to parse erc20 abi: " + err.Error())
+	}
+}
+
+const erc20ABIJSON = `
+[
+	{
+		"constant": false,
+		"inputs": [
+			{ "name": "_to", "type": "address" },
+			{ "name": "_value", "type": "uint256" }
+		],
+		"name": "transfer",
+		"outputs": [{ "name": "", "type": "bool" }],
+		"payable": false,
+		"stateMutability": "nonpayable",
+		"type": "function"
+	},
+	{
+		"constant": true,
+		"inputs": [],
+		"name": "decimals",
+		"outputs": [{ "name": "", "type": "uint8" }],
+		"payable": false,
+		"stateMutability": "view",
+        "type": "function"
+	}
+]`
+
+// NormalizeAddress validates and normalizes EVM hex addresses.
+func NormalizeAddress(address string) (string, error) {
+	trimmed := strings.TrimSpace(address)
+	if trimmed == "" {
+		return "", merrors.InvalidArgument("address is required")
+	}
+	if !common.IsHexAddress(trimmed) {
+		return "", merrors.InvalidArgument("invalid hex address")
+	}
+	return strings.ToLower(common.HexToAddress(trimmed).Hex()), nil
+}
+
+func nativeCurrency(network shared.Network) string {
+	currency := strings.ToUpper(strings.TrimSpace(network.NativeToken))
+	if currency == "" {
+		currency = strings.ToUpper(network.Name)
+	}
+	return currency
+}
+
+func parseBaseUnitAmount(amount string) (*big.Int, error) {
+	trimmed := strings.TrimSpace(amount)
+	if trimmed == "" {
+		return nil, merrors.InvalidArgument("amount is required")
+	}
+	value, ok := new(big.Int).SetString(trimmed, 10)
+	if !ok {
+		return nil, merrors.InvalidArgument("invalid amount")
+	}
+	if value.Sign() < 0 {
+		return nil, merrors.InvalidArgument("amount must be non-negative")
+	}
+	return value, nil
+}
+
+// Balance fetches ERC20 token balance for the provided address.
+func Balance(ctx context.Context, deps driver.Deps, network shared.Network, wallet *model.ManagedWallet, address string) (*moneyv1.Money, error) {
+	logger := deps.Logger
+	registry := deps.Registry
+
+	if registry == nil {
+		return nil, merrors.Internal("rpc clients not initialised")
+	}
+	if wallet == nil {
+		return nil, merrors.InvalidArgument("wallet is required")
+	}
+
+	normalizedAddress, err := NormalizeAddress(address)
+	if err != nil {
+		return nil, err
+	}
+
+	rpcURL := strings.TrimSpace(network.RPCURL)
+	logFields := []zap.Field{
+		zap.String("wallet_ref", wallet.WalletRef),
+		zap.String("network", strings.ToLower(strings.TrimSpace(network.Name))),
+		zap.String("token_symbol", strings.ToUpper(strings.TrimSpace(wallet.TokenSymbol))),
+		zap.String("contract", strings.ToLower(strings.TrimSpace(wallet.ContractAddress))),
+		zap.String("wallet_address", normalizedAddress),
+	}
+	if rpcURL == "" {
+		logger.Warn("Network rpc url is not configured", logFields...)
+		return nil, merrors.Internal("network rpc url is not configured")
+	}
+
+	contract := strings.TrimSpace(wallet.ContractAddress)
+	if contract == "" {
+		logger.Debug("Native balance requested", logFields...)
+		return NativeBalance(ctx, deps, network, wallet, normalizedAddress)
+	}
+	if !common.IsHexAddress(contract) {
+		logger.Warn("Invalid contract address for balance fetch", logFields...)
+		return nil, merrors.InvalidArgument("invalid contract address")
+	}
+
+	logger.Info("Fetching on-chain wallet balance", logFields...)
+
+	rpcClient, err := registry.RPCClient(network.Name)
+	if err != nil {
+		logger.Warn("Failed to fetch rpc client", append(logFields, zap.Error(err))...)
+		return nil, err
+	}
+
+	timeout := deps.RPCTimeout
+	if timeout <= 0 {
+		timeout = 10 * time.Second
+	}
+	timeoutCtx, cancel := context.WithTimeout(ctx, timeout)
+	defer cancel()
+
+	logger.Debug("Calling token decimals", logFields...)
+	decimals, err := readDecimals(timeoutCtx, rpcClient, contract)
+	if err != nil {
+		logger.Warn("Token decimals call failed", append(logFields, zap.Error(err))...)
+		return nil, err
+	}
+
+	logger.Debug("Calling token balanceOf", append(logFields, zap.Uint8("decimals", decimals))...)
+	bal, err := readBalanceOf(timeoutCtx, rpcClient, contract, normalizedAddress)
+	if err != nil {
+		logger.Warn("Token balanceOf call failed", append(logFields, zap.Uint8("decimals", decimals), zap.Error(err))...)
+		return nil, err
+	}
+
+	dec := decimal.NewFromBigInt(bal, 0).Shift(-int32(decimals))
+	logger.Info("On-chain wallet balance fetched",
+		append(logFields,
+			zap.Uint8("decimals", decimals),
+			zap.String("balance_raw", bal.String()),
+			zap.String("balance", dec.String()),
+		)...,
+	)
+	return &moneyv1.Money{Currency: wallet.TokenSymbol, Amount: dec.String()}, nil
+}
+
+// NativeBalance fetches native token balance for the provided address.
+func NativeBalance(ctx context.Context, deps driver.Deps, network shared.Network, wallet *model.ManagedWallet, address string) (*moneyv1.Money, error) {
+	logger := deps.Logger
+	registry := deps.Registry
+
+	if registry == nil {
+		return nil, merrors.Internal("rpc clients not initialised")
+	}
+	if wallet == nil {
+		return nil, merrors.InvalidArgument("wallet is required")
+	}
+
+	normalizedAddress, err := NormalizeAddress(address)
+	if err != nil {
+		return nil, err
+	}
+
+	rpcURL := strings.TrimSpace(network.RPCURL)
+	logFields := []zap.Field{
+		zap.String("wallet_ref", wallet.WalletRef),
+		zap.String("network", strings.ToLower(strings.TrimSpace(network.Name))),
+		zap.String("wallet_address", normalizedAddress),
+	}
+	if rpcURL == "" {
+		logger.Warn("Network rpc url is not configured", logFields...)
+		return nil, merrors.Internal("network rpc url is not configured")
+	}
+
+	client, err := registry.Client(network.Name)
+	if err != nil {
+		logger.Warn("Failed to fetch rpc client", append(logFields, zap.Error(err))...)
+		return nil, err
+	}
+
+	timeout := deps.RPCTimeout
+	if timeout <= 0 {
+		timeout = 10 * time.Second
+	}
+	timeoutCtx, cancel := context.WithTimeout(ctx, timeout)
+	defer cancel()
+
+	bal, err := client.BalanceAt(timeoutCtx, common.HexToAddress(normalizedAddress), nil)
+	if err != nil {
+		logger.Warn("Native balance call failed", append(logFields, zap.Error(err))...)
+		return nil, err
+	}
+
+	logger.Info("On-chain native balance fetched",
+		append(logFields,
+			zap.String("balance_raw", bal.String()),
+		)...,
+	)
+	return &moneyv1.Money{
+		Currency: nativeCurrency(network),
+		Amount:   bal.String(),
+	}, nil
+}
+
+// EstimateFee estimates ERC20 transfer fees for the given parameters.
+func EstimateFee(ctx context.Context, deps driver.Deps, network shared.Network, wallet *model.ManagedWallet, fromAddress, destination string, amount *moneyv1.Money) (*moneyv1.Money, error) {
+	logger := deps.Logger
+	registry := deps.Registry
+
+	if registry == nil {
+		return nil, merrors.Internal("rpc clients not initialised")
+	}
+	if wallet == nil {
+		return nil, merrors.InvalidArgument("wallet is required")
+	}
+	if amount == nil {
+		return nil, merrors.InvalidArgument("amount is required")
+	}
+
+	rpcURL := strings.TrimSpace(network.RPCURL)
+	if rpcURL == "" {
+		return nil, merrors.InvalidArgument("network rpc url not configured")
+	}
+	if _, err := NormalizeAddress(fromAddress); err != nil {
+		return nil, merrors.InvalidArgument("invalid source wallet address")
+	}
+	if _, err := NormalizeAddress(destination); err != nil {
+		return nil, merrors.InvalidArgument("invalid destination address")
+	}
+
+	client, err := registry.Client(network.Name)
+	if err != nil {
+		return nil, err
+	}
+	rpcClient, err := registry.RPCClient(network.Name)
+	if err != nil {
+		return nil, err
+	}
+
+	timeout := deps.RPCTimeout
+	if timeout <= 0 {
+		timeout = 15 * time.Second
+	}
+	timeoutCtx, cancel := context.WithTimeout(ctx, timeout)
+	defer cancel()
+
+	contract := strings.TrimSpace(wallet.ContractAddress)
+	toAddr := common.HexToAddress(destination)
+	fromAddr := common.HexToAddress(fromAddress)
+
+	if contract == "" {
+		amountBase, err := parseBaseUnitAmount(amount.GetAmount())
+		if err != nil {
+			return nil, err
+		}
+		gasPrice, err := client.SuggestGasPrice(timeoutCtx)
+		if err != nil {
+			return nil, merrors.Internal("failed to suggest gas price: " + err.Error())
+		}
+		callMsg := ethereum.CallMsg{
+			From:     fromAddr,
+			To:       &toAddr,
+			GasPrice: gasPrice,
+			Value:    amountBase,
+		}
+		gasLimit, err := client.EstimateGas(timeoutCtx, callMsg)
+		if err != nil {
+			return nil, merrors.Internal("failed to estimate gas: " + err.Error())
+		}
+		fee := new(big.Int).Mul(gasPrice, new(big.Int).SetUint64(gasLimit))
+		feeDec := decimal.NewFromBigInt(fee, 0)
+		return &moneyv1.Money{
+			Currency: nativeCurrency(network),
+			Amount:   feeDec.String(),
+		}, nil
+	}
+	if !common.IsHexAddress(contract) {
+		return nil, merrors.InvalidArgument("invalid token contract address")
+	}
+
+	tokenAddr := common.HexToAddress(contract)
+
+	decimals, err := erc20Decimals(timeoutCtx, rpcClient, tokenAddr)
+	if err != nil {
+		logger.Warn("Failed to read token decimals", zap.Error(err))
+		return nil, err
+	}
+
+	amountBase, err := toBaseUnits(strings.TrimSpace(amount.GetAmount()), decimals)
+	if err != nil {
+		return nil, err
+	}
+
+	input, err := erc20ABI.Pack("transfer", toAddr, amountBase)
+	if err != nil {
+		return nil, merrors.Internal("failed to encode transfer call: " + err.Error())
+	}
+
+	gasPrice, err := client.SuggestGasPrice(timeoutCtx)
+	if err != nil {
+		return nil, merrors.Internal("failed to suggest gas price: " + err.Error())
+	}
+
+	callMsg := ethereum.CallMsg{
+		From:     fromAddr,
+		To:       &tokenAddr,
+		GasPrice: gasPrice,
+		Data:     input,
+	}
+	gasLimit, err := client.EstimateGas(timeoutCtx, callMsg)
+	if err != nil {
+		return nil, merrors.Internal("failed to estimate gas: " + err.Error())
+	}
+
+	fee := new(big.Int).Mul(gasPrice, new(big.Int).SetUint64(gasLimit))
+	feeDec := decimal.NewFromBigInt(fee, 0)
+
+	return &moneyv1.Money{
+		Currency: nativeCurrency(network),
+		Amount:   feeDec.String(),
+	}, nil
+}
+
+// SubmitTransfer submits an ERC20 transfer on an EVM-compatible chain.
+func SubmitTransfer(ctx context.Context, deps driver.Deps, network shared.Network, transfer *model.Transfer, source *model.ManagedWallet, fromAddress, destination string) (string, error) {
+	logger := deps.Logger
+	registry := deps.Registry
+
+	if deps.KeyManager == nil {
+		logger.Warn("Key manager not configured")
+		return "", executorInternal("key manager is not configured", nil)
+	}
+	if registry == nil {
+		return "", executorInternal("rpc clients not initialised", nil)
+	}
+	rpcURL := strings.TrimSpace(network.RPCURL)
+	if rpcURL == "" {
+		logger.Warn("Network rpc url missing", zap.String("network", network.Name))
+		return "", executorInvalid("network rpc url is not configured")
+	}
+	if source == nil || transfer == nil {
+		logger.Warn("Transfer context missing")
+		return "", executorInvalid("transfer context missing")
+	}
+	if strings.TrimSpace(source.KeyReference) == "" {
+		logger.Warn("Source wallet missing key reference", zap.String("wallet_ref", source.WalletRef))
+		return "", executorInvalid("source wallet missing key reference")
+	}
+	if _, err := NormalizeAddress(fromAddress); err != nil {
+		logger.Warn("Invalid source wallet address", zap.String("wallet_ref", source.WalletRef))
+		return "", executorInvalid("invalid source wallet address")
+	}
+	if _, err := NormalizeAddress(destination); err != nil {
+		logger.Warn("Invalid destination address", zap.String("transfer_ref", transfer.TransferRef), zap.String("address", destination))
+		return "", executorInvalid("invalid destination address " + destination)
+	}
+
+	logger.Info("submitting transfer",
+		zap.String("transfer_ref", transfer.TransferRef),
+		zap.String("source_wallet_ref", source.WalletRef),
+		zap.String("network", network.Name),
+		zap.String("destination", strings.ToLower(destination)),
+	)
+
+	client, err := registry.Client(network.Name)
+	if err != nil {
+		logger.Warn("Failed to initialise rpc client", zap.Error(err), zap.String("network", network.Name))
+		return "", err
+	}
+	rpcClient, err := registry.RPCClient(network.Name)
+	if err != nil {
+		logger.Warn("failed to initialise rpc client", zap.String("network", network.Name))
+		return "", err
+	}
+
+	sourceAddress := common.HexToAddress(fromAddress)
+	destinationAddr := common.HexToAddress(destination)
+
+	ctx, cancel := context.WithTimeout(ctx, 60*time.Second)
+	defer cancel()
+
+	nonce, err := client.PendingNonceAt(ctx, sourceAddress)
+	if err != nil {
+		logger.Warn("Failed to fetch nonce", zap.Error(err),
+			zap.String("transfer_ref", transfer.TransferRef),
+			zap.String("wallet_ref", source.WalletRef),
+		)
+		return "", executorInternal("failed to fetch nonce", err)
+	}
+
+	gasPrice, err := client.SuggestGasPrice(ctx)
+	if err != nil {
+		logger.Warn("Failed to suggest gas price", zap.Error(err),
+			zap.String("transfer_ref", transfer.TransferRef),
+			zap.String("network", network.Name),
+		)
+		return "", executorInternal("failed to suggest gas price", err)
+	}
+
+	chainID := new(big.Int).SetUint64(network.ChainID)
+
+	contract := strings.TrimSpace(transfer.ContractAddress)
+	amount := transfer.NetAmount
+	if amount == nil || strings.TrimSpace(amount.Amount) == "" {
+		logger.Warn("Transfer missing net amount", zap.String("transfer_ref", transfer.TransferRef))
+		return "", executorInvalid("transfer missing net amount")
+	}
+
+	var tx *types.Transaction
+	if contract == "" {
+		amountInt, err := parseBaseUnitAmount(amount.Amount)
+		if err != nil {
+			logger.Warn("Invalid native amount", zap.Error(err), zap.String("transfer_ref", transfer.TransferRef))
+			return "", err
+		}
+		callMsg := ethereum.CallMsg{
+			From:     sourceAddress,
+			To:       &destinationAddr,
+			GasPrice: gasPrice,
+			Value:    amountInt,
+		}
+		gasLimit, err := client.EstimateGas(ctx, callMsg)
+		if err != nil {
+			logger.Warn("Failed to estimate gas", zap.Error(err),
+				zap.String("transfer_ref", transfer.TransferRef),
+			)
+			return "", executorInternal("failed to estimate gas", err)
+		}
+		tx = types.NewTransaction(nonce, destinationAddr, amountInt, gasLimit, gasPrice, nil)
+	} else {
+		if !common.IsHexAddress(contract) {
+			logger.Warn("Invalid token contract address",
+				zap.String("transfer_ref", transfer.TransferRef),
+				zap.String("contract", contract),
+			)
+			return "", executorInvalid("invalid token contract address " + contract)
+		}
+		tokenAddress := common.HexToAddress(contract)
+
+		decimals, err := erc20Decimals(ctx, rpcClient, tokenAddress)
+		if err != nil {
+			logger.Warn("Failed to read token decimals", zap.Error(err),
+				zap.String("transfer_ref", transfer.TransferRef),
+				zap.String("contract", contract),
+			)
+			return "", err
+		}
+
+		amountInt, err := toBaseUnits(amount.Amount, decimals)
+		if err != nil {
+			logger.Warn("Failed to convert amount to base units", zap.Error(err),
+				zap.String("transfer_ref", transfer.TransferRef),
+				zap.String("amount", amount.Amount),
+			)
+			return "", err
+		}
+
+		input, err := erc20ABI.Pack("transfer", destinationAddr, amountInt)
+		if err != nil {
+			logger.Warn("Failed to encode transfer call", zap.Error(err),
+				zap.String("transfer_ref", transfer.TransferRef),
+			)
+			return "", executorInternal("failed to encode transfer call", err)
+		}
+
+		callMsg := ethereum.CallMsg{
+			From:     sourceAddress,
+			To:       &tokenAddress,
+			GasPrice: gasPrice,
+			Data:     input,
+		}
+		gasLimit, err := client.EstimateGas(ctx, callMsg)
+		if err != nil {
+			logger.Warn("Failed to estimate gas", zap.Error(err),
+				zap.String("transfer_ref", transfer.TransferRef),
+			)
+			return "", executorInternal("failed to estimate gas", err)
+		}
+
+		tx = types.NewTransaction(nonce, tokenAddress, big.NewInt(0), gasLimit, gasPrice, input)
+	}
+
+	signedTx, err := deps.KeyManager.SignTransaction(ctx, source.KeyReference, tx, chainID)
+	if err != nil {
+		logger.Warn("Failed to sign transaction", zap.Error(err),
+			zap.String("transfer_ref", transfer.TransferRef),
+			zap.String("wallet_ref", source.WalletRef),
+		)
+		return "", err
+	}
+
+	if err := client.SendTransaction(ctx, signedTx); err != nil {
+		logger.Warn("Failed to send transaction", zap.Error(err),
+			zap.String("transfer_ref", transfer.TransferRef),
+		)
+		return "", executorInternal("failed to send transaction", err)
+	}
+
+	txHash := signedTx.Hash().Hex()
+	logger.Info("Transaction submitted",
+		zap.String("transfer_ref", transfer.TransferRef),
+		zap.String("tx_hash", txHash),
+		zap.String("network", network.Name),
+	)
+
+	return txHash, nil
+}
+
+// AwaitConfirmation waits for the transaction receipt.
+func AwaitConfirmation(ctx context.Context, deps driver.Deps, network shared.Network, txHash string) (*types.Receipt, error) {
+	logger := deps.Logger
+	registry := deps.Registry
+
+	if strings.TrimSpace(txHash) == "" {
+		logger.Warn("Missing transaction hash for confirmation", zap.String("network", network.Name))
+		return nil, executorInvalid("tx hash is required")
+	}
+	rpcURL := strings.TrimSpace(network.RPCURL)
+	if rpcURL == "" {
+		logger.Warn("Network rpc url missing while awaiting confirmation", zap.String("tx_hash", txHash))
+		return nil, executorInvalid("network rpc url is not configured")
+	}
+	if registry == nil {
+		return nil, executorInternal("rpc clients not initialised", nil)
+	}
+
+	client, err := registry.Client(network.Name)
+	if err != nil {
+		return nil, err
+	}
+
+	hash := common.HexToHash(txHash)
+	ticker := time.NewTicker(3 * time.Second)
+	defer ticker.Stop()
+
+	for {
+		receipt, err := client.TransactionReceipt(ctx, hash)
+		if err != nil {
+			if errors.Is(err, ethereum.NotFound) {
+				select {
+				case <-ticker.C:
+					logger.Debug("Transaction not yet mined",
+						zap.String("tx_hash", txHash),
+						zap.String("network", network.Name),
+					)
+					continue
+				case <-ctx.Done():
+					logger.Warn("Context cancelled while awaiting confirmation",
+						zap.String("tx_hash", txHash),
+						zap.String("network", network.Name),
+					)
+					return nil, ctx.Err()
+				}
+			}
+			logger.Warn("Failed to fetch transaction receipt",
+				zap.String("tx_hash", txHash),
+				zap.String("network", network.Name),
+				zap.Error(err),
+			)
+			return nil, executorInternal("failed to fetch transaction receipt", err)
+		}
+		logger.Info("Transaction confirmed",
+			zap.String("tx_hash", txHash),
+			zap.String("network", network.Name),
+			zap.Uint64("block_number", receipt.BlockNumber.Uint64()),
+			zap.Uint64("status", receipt.Status),
+		)
+		return receipt, nil
+	}
+}
+
+func readDecimals(ctx context.Context, client *rpc.Client, token string) (uint8, error) {
+	call := map[string]string{
+		"to":   strings.ToLower(common.HexToAddress(token).Hex()),
+		"data": "0x313ce567",
+	}
+	var hexResp string
+	if err := client.CallContext(ctx, &hexResp, "eth_call", call, "latest"); err != nil {
+		return 0, merrors.Internal("decimals call failed: " + err.Error())
+	}
+	val, err := shared.DecodeHexUint8(hexResp)
+	if err != nil {
+		return 0, merrors.Internal("decimals decode failed: " + err.Error())
+	}
+	return val, nil
+}
+
+func readBalanceOf(ctx context.Context, client *rpc.Client, token string, wallet string) (*big.Int, error) {
+	tokenAddr := common.HexToAddress(token)
+	walletAddr := common.HexToAddress(wallet)
+	addr := strings.TrimPrefix(walletAddr.Hex(), "0x")
+	if len(addr) < 64 {
+		addr = strings.Repeat("0", 64-len(addr)) + addr
+	}
+	call := map[string]string{
+		"to":   strings.ToLower(tokenAddr.Hex()),
+		"data": "0x70a08231" + addr,
+	}
+	var hexResp string
+	if err := client.CallContext(ctx, &hexResp, "eth_call", call, "latest"); err != nil {
+		return nil, merrors.Internal("balanceOf call failed: " + err.Error())
+	}
+	bigVal, err := shared.DecodeHexBig(hexResp)
+	if err != nil {
+		return nil, merrors.Internal("balanceOf decode failed: " + err.Error())
+	}
+	return bigVal, nil
+}
+
+func erc20Decimals(ctx context.Context, client *rpc.Client, token common.Address) (uint8, error) {
+	call := map[string]string{
+		"to":   strings.ToLower(token.Hex()),
+		"data": "0x313ce567",
+	}
+	var hexResp string
+	if err := client.CallContext(ctx, &hexResp, "eth_call", call, "latest"); err != nil {
+		return 0, executorInternal("decimals call failed", err)
+	}
+	val, err := shared.DecodeHexUint8(hexResp)
+	if err != nil {
+		return 0, executorInternal("decimals decode failed", err)
+	}
+	return val, nil
+}
+
+func toBaseUnits(amount string, decimals uint8) (*big.Int, error) {
+	value, err := decimal.NewFromString(strings.TrimSpace(amount))
+	if err != nil {
+		return nil, merrors.InvalidArgument("invalid amount " + amount + ": " + err.Error())
+	}
+	if value.IsNegative() {
+		return nil, merrors.InvalidArgument("amount must be positive")
+	}
+	multiplier := decimal.NewFromInt(1).Shift(int32(decimals))
+	scaled := value.Mul(multiplier)
+	if !scaled.Equal(scaled.Truncate(0)) {
+		return nil, merrors.InvalidArgument("amount " + amount + " exceeds token precision")
+	}
+	return scaled.BigInt(), nil
+}
+
+func executorInvalid(msg string) error {
+	return merrors.InvalidArgument("executor: " + msg)
+}
+
+func executorInternal(msg string, err error) error {
+	if err != nil {
+		msg = msg + ": " + err.Error()
+	}
+	return merrors.Internal("executor: " + msg)
+}

api/gateway/chain/internal/service/gateway/driver/evm/gas_topup.go

@@ -0,0 +1,108 @@
+package evm
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/shopspring/decimal"
+	"github.com/tech/sendico/gateway/chain/internal/service/gateway/shared"
+	"github.com/tech/sendico/gateway/chain/storage/model"
+	"github.com/tech/sendico/pkg/merrors"
+	moneyv1 "github.com/tech/sendico/pkg/proto/common/money/v1"
+)
+
+var evmBaseUnitFactor = decimal.NewFromInt(1_000_000_000_000_000_000)
+
+// ComputeGasTopUp applies the network policy to decide an EVM native-token top-up amount.
+func ComputeGasTopUp(network shared.Network, wallet *model.ManagedWallet, estimatedFee *moneyv1.Money, currentBalance *moneyv1.Money) (*moneyv1.Money, bool, error) {
+	if wallet == nil {
+		return nil, false, merrors.InvalidArgument("wallet is required")
+	}
+	if estimatedFee == nil || strings.TrimSpace(estimatedFee.GetAmount()) == "" || strings.TrimSpace(estimatedFee.GetCurrency()) == "" {
+		return nil, false, merrors.InvalidArgument("estimated fee is required")
+	}
+	if currentBalance == nil || strings.TrimSpace(currentBalance.GetAmount()) == "" || strings.TrimSpace(currentBalance.GetCurrency()) == "" {
+		return nil, false, merrors.InvalidArgument("current native balance is required")
+	}
+	if network.GasTopUpPolicy == nil {
+		return nil, false, merrors.InvalidArgument("gas top-up policy is not configured")
+	}
+
+	nativeCurrency := strings.TrimSpace(network.NativeToken)
+	if nativeCurrency == "" {
+		nativeCurrency = strings.ToUpper(strings.TrimSpace(network.Name))
+	}
+	if !strings.EqualFold(nativeCurrency, estimatedFee.GetCurrency()) {
+		return nil, false, merrors.InvalidArgument(fmt.Sprintf("estimated fee currency mismatch (expected %s)", nativeCurrency))
+	}
+	if !strings.EqualFold(nativeCurrency, currentBalance.GetCurrency()) {
+		return nil, false, merrors.InvalidArgument(fmt.Sprintf("native balance currency mismatch (expected %s)", nativeCurrency))
+	}
+
+	estimatedNative, err := evmToNative(estimatedFee)
+	if err != nil {
+		return nil, false, err
+	}
+	currentNative, err := evmToNative(currentBalance)
+	if err != nil {
+		return nil, false, err
+	}
+
+	isContract := strings.TrimSpace(wallet.ContractAddress) != ""
+	rule, ok := network.GasTopUpPolicy.Rule(isContract)
+	if !ok {
+		return nil, false, merrors.InvalidArgument("gas top-up policy is not configured")
+	}
+	if rule.RoundingUnit.LessThanOrEqual(decimal.Zero) {
+		return nil, false, merrors.InvalidArgument("gas top-up rounding unit must be > 0")
+	}
+	if rule.MaxTopUp.LessThanOrEqual(decimal.Zero) {
+		return nil, false, merrors.InvalidArgument("gas top-up max top-up must be > 0")
+	}
+
+	required := estimatedNative.Sub(currentNative)
+	if required.IsNegative() {
+		required = decimal.Zero
+	}
+	bufferedRequired := required.Mul(decimal.NewFromInt(1).Add(rule.BufferPercent))
+
+	minBalanceTopUp := rule.MinNativeBalance.Sub(currentNative)
+	if minBalanceTopUp.IsNegative() {
+		minBalanceTopUp = decimal.Zero
+	}
+
+	rawTopUp := bufferedRequired
+	if minBalanceTopUp.GreaterThan(rawTopUp) {
+		rawTopUp = minBalanceTopUp
+	}
+
+	roundedTopUp := decimal.Zero
+	if rawTopUp.IsPositive() {
+		roundedTopUp = rawTopUp.Div(rule.RoundingUnit).Ceil().Mul(rule.RoundingUnit)
+	}
+
+	topUp := roundedTopUp
+	capHit := false
+	if topUp.GreaterThan(rule.MaxTopUp) {
+		topUp = rule.MaxTopUp
+		capHit = true
+	}
+
+	if !topUp.IsPositive() {
+		return nil, capHit, nil
+	}
+
+	baseUnits := topUp.Mul(evmBaseUnitFactor).Ceil().Truncate(0)
+	return &moneyv1.Money{
+		Currency: strings.ToUpper(nativeCurrency),
+		Amount:   baseUnits.StringFixed(0),
+	}, capHit, nil
+}
+
+func evmToNative(amount *moneyv1.Money) (decimal.Decimal, error) {
+	value, err := decimal.NewFromString(strings.TrimSpace(amount.GetAmount()))
+	if err != nil {
+		return decimal.Zero, err
+	}
+	return value.Div(evmBaseUnitFactor), nil
+}

api/gateway/chain/internal/service/gateway/driver/evm/gas_topup_test.go

@@ -0,0 +1,146 @@
+package evm
+
+import (
+	"testing"
+
+	"github.com/shopspring/decimal"
+	"github.com/stretchr/testify/require"
+	"github.com/tech/sendico/gateway/chain/internal/service/gateway/shared"
+	"github.com/tech/sendico/gateway/chain/storage/model"
+	moneyv1 "github.com/tech/sendico/pkg/proto/common/money/v1"
+)
+
+func TestComputeGasTopUp_BalanceSufficient(t *testing.T) {
+	network := ethNetwork(defaultPolicy())
+	wallet := &model.ManagedWallet{}
+
+	topUp, capHit, err := ComputeGasTopUp(network, wallet, ethMoney("5"), ethMoney("30"))
+	require.NoError(t, err)
+	require.Nil(t, topUp)
+	require.False(t, capHit)
+}
+
+func TestComputeGasTopUp_BufferedRequired(t *testing.T) {
+	network := ethNetwork(defaultPolicy())
+	wallet := &model.ManagedWallet{}
+
+	topUp, capHit, err := ComputeGasTopUp(network, wallet, ethMoney("50"), ethMoney("10"))
+	require.NoError(t, err)
+	require.NotNil(t, topUp)
+	require.False(t, capHit)
+	require.Equal(t, "46000000000000000000", topUp.GetAmount())
+	require.Equal(t, "ETH", topUp.GetCurrency())
+}
+
+func TestComputeGasTopUp_MinBalanceBinding(t *testing.T) {
+	network := ethNetwork(defaultPolicy())
+	wallet := &model.ManagedWallet{}
+
+	topUp, capHit, err := ComputeGasTopUp(network, wallet, ethMoney("5"), ethMoney("1"))
+	require.NoError(t, err)
+	require.NotNil(t, topUp)
+	require.False(t, capHit)
+	require.Equal(t, "19000000000000000000", topUp.GetAmount())
+}
+
+func TestComputeGasTopUp_RoundsUp(t *testing.T) {
+	policy := shared.GasTopUpPolicy{
+		Default: shared.GasTopUpRule{
+			BufferPercent:    decimal.NewFromFloat(0),
+			MinNativeBalance: decimal.NewFromFloat(0),
+			RoundingUnit:     decimal.NewFromFloat(1),
+			MaxTopUp:         decimal.NewFromFloat(100),
+		},
+	}
+	network := ethNetwork(&policy)
+	wallet := &model.ManagedWallet{}
+
+	topUp, capHit, err := ComputeGasTopUp(network, wallet, ethMoney("1.1"), ethMoney("0"))
+	require.NoError(t, err)
+	require.NotNil(t, topUp)
+	require.False(t, capHit)
+	require.Equal(t, "2000000000000000000", topUp.GetAmount())
+}
+
+func TestComputeGasTopUp_CapHit(t *testing.T) {
+	policy := shared.GasTopUpPolicy{
+		Default: shared.GasTopUpRule{
+			BufferPercent:    decimal.NewFromFloat(0),
+			MinNativeBalance: decimal.NewFromFloat(0),
+			RoundingUnit:     decimal.NewFromFloat(1),
+			MaxTopUp:         decimal.NewFromFloat(10),
+		},
+	}
+	network := ethNetwork(&policy)
+	wallet := &model.ManagedWallet{}
+
+	topUp, capHit, err := ComputeGasTopUp(network, wallet, ethMoney("100"), ethMoney("0"))
+	require.NoError(t, err)
+	require.NotNil(t, topUp)
+	require.True(t, capHit)
+	require.Equal(t, "10000000000000000000", topUp.GetAmount())
+}
+
+func TestComputeGasTopUp_MinBalanceWhenRequiredZero(t *testing.T) {
+	network := ethNetwork(defaultPolicy())
+	wallet := &model.ManagedWallet{}
+
+	topUp, capHit, err := ComputeGasTopUp(network, wallet, ethMoney("0"), ethMoney("5"))
+	require.NoError(t, err)
+	require.NotNil(t, topUp)
+	require.False(t, capHit)
+	require.Equal(t, "15000000000000000000", topUp.GetAmount())
+}
+
+func TestComputeGasTopUp_ContractPolicyOverride(t *testing.T) {
+	policy := shared.GasTopUpPolicy{
+		Default: shared.GasTopUpRule{
+			BufferPercent:    decimal.NewFromFloat(0.1),
+			MinNativeBalance: decimal.NewFromFloat(10),
+			RoundingUnit:     decimal.NewFromFloat(1),
+			MaxTopUp:         decimal.NewFromFloat(100),
+		},
+		Contract: &shared.GasTopUpRule{
+			BufferPercent:    decimal.NewFromFloat(0.5),
+			MinNativeBalance: decimal.NewFromFloat(5),
+			RoundingUnit:     decimal.NewFromFloat(1),
+			MaxTopUp:         decimal.NewFromFloat(100),
+		},
+	}
+	network := ethNetwork(&policy)
+	wallet := &model.ManagedWallet{ContractAddress: "0xcontract"}
+
+	topUp, capHit, err := ComputeGasTopUp(network, wallet, ethMoney("10"), ethMoney("0"))
+	require.NoError(t, err)
+	require.NotNil(t, topUp)
+	require.False(t, capHit)
+	require.Equal(t, "15000000000000000000", topUp.GetAmount())
+}
+
+func defaultPolicy() *shared.GasTopUpPolicy {
+	return &shared.GasTopUpPolicy{
+		Default: shared.GasTopUpRule{
+			BufferPercent:    decimal.NewFromFloat(0.15),
+			MinNativeBalance: decimal.NewFromFloat(20),
+			RoundingUnit:     decimal.NewFromFloat(1),
+			MaxTopUp:         decimal.NewFromFloat(500),
+		},
+	}
+}
+
+func ethNetwork(policy *shared.GasTopUpPolicy) shared.Network {
+	return shared.Network{
+		Name:           "ethereum_mainnet",
+		NativeToken:    "ETH",
+		GasTopUpPolicy: policy,
+	}
+}
+
+func ethMoney(eth string) *moneyv1.Money {
+	value, _ := decimal.NewFromString(eth)
+	baseUnits := value.Mul(evmBaseUnitFactor).Truncate(0)
+	return &moneyv1.Money{
+		Currency: "ETH",
+		Amount:   baseUnits.StringFixed(0),
+	}
+}

api/gateway/chain/internal/service/gateway/driver/tron/address.go

@@ -0,0 +1,193 @@
+package tron
+
+import (
+	"bytes"
+	"crypto/sha256"
+	"encoding/hex"
+	"fmt"
+	"math/big"
+	"strings"
+
+	"github.com/tech/sendico/pkg/merrors"
+)
+
+const tronHexPrefix = "0x"
+
+var base58Alphabet = []byte("123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz")
+
+func normalizeAddress(address string) (string, error) {
+	trimmed := strings.TrimSpace(address)
+	if trimmed == "" {
+		return "", merrors.InvalidArgument("address is required")
+	}
+	if strings.HasPrefix(trimmed, tronHexPrefix) || isHexString(trimmed) {
+		return hexToBase58(trimmed)
+	}
+	decoded, err := base58Decode(trimmed)
+	if err != nil {
+		return "", err
+	}
+	if err := validateChecksum(decoded); err != nil {
+		return "", err
+	}
+	return base58Encode(decoded), nil
+}
+
+func rpcAddress(address string) (string, error) {
+	trimmed := strings.TrimSpace(address)
+	if trimmed == "" {
+		return "", merrors.InvalidArgument("address is required")
+	}
+	if strings.HasPrefix(trimmed, tronHexPrefix) || isHexString(trimmed) {
+		return normalizeHexRPC(trimmed)
+	}
+	return base58ToHex(trimmed)
+}
+
+func hexToBase58(address string) (string, error) {
+	bytesAddr, err := parseHexAddress(address)
+	if err != nil {
+		return "", err
+	}
+	payload := append(bytesAddr, checksum(bytesAddr)...)
+	return base58Encode(payload), nil
+}
+
+func base58ToHex(address string) (string, error) {
+	decoded, err := base58Decode(address)
+	if err != nil {
+		return "", err
+	}
+	if err := validateChecksum(decoded); err != nil {
+		return "", err
+	}
+	return tronHexPrefix + hex.EncodeToString(decoded[1:21]), nil
+}
+
+func parseHexAddress(address string) ([]byte, error) {
+	trimmed := strings.TrimPrefix(strings.TrimSpace(address), tronHexPrefix)
+	if trimmed == "" {
+		return nil, merrors.InvalidArgument("address is required")
+	}
+	if len(trimmed)%2 == 1 {
+		trimmed = "0" + trimmed
+	}
+	decoded, err := hex.DecodeString(trimmed)
+	if err != nil {
+		return nil, merrors.InvalidArgument("invalid hex address")
+	}
+	switch len(decoded) {
+	case 20:
+		prefixed := make([]byte, 21)
+		prefixed[0] = 0x41
+		copy(prefixed[1:], decoded)
+		return prefixed, nil
+	case 21:
+		if decoded[0] != 0x41 {
+			return nil, merrors.InvalidArgument("invalid tron address prefix")
+		}
+		return decoded, nil
+	default:
+		return nil, merrors.InvalidArgument(fmt.Sprintf("invalid tron address length %d", len(decoded)))
+	}
+}
+
+func normalizeHexRPC(address string) (string, error) {
+	decoded, err := parseHexAddress(address)
+	if err != nil {
+		return "", err
+	}
+	return tronHexPrefix + hex.EncodeToString(decoded[1:21]), nil
+}
+
+func validateChecksum(decoded []byte) error {
+	if len(decoded) != 25 {
+		return merrors.InvalidArgument("invalid tron address length")
+	}
+	payload := decoded[:21]
+	expected := checksum(payload)
+	if !bytes.Equal(expected, decoded[21:]) {
+		return merrors.InvalidArgument("invalid tron address checksum")
+	}
+	if payload[0] != 0x41 {
+		return merrors.InvalidArgument("invalid tron address prefix")
+	}
+	return nil
+}
+
+func checksum(payload []byte) []byte {
+	first := sha256.Sum256(payload)
+	second := sha256.Sum256(first[:])
+	return second[:4]
+}
+
+func base58Encode(input []byte) string {
+	if len(input) == 0 {
+		return ""
+	}
+	x := new(big.Int).SetBytes(input)
+	base := big.NewInt(58)
+	zero := big.NewInt(0)
+	mod := new(big.Int)
+
+	encoded := make([]byte, 0, len(input))
+	for x.Cmp(zero) > 0 {
+		x.DivMod(x, base, mod)
+		encoded = append(encoded, base58Alphabet[mod.Int64()])
+	}
+	for _, b := range input {
+		if b != 0 {
+			break
+		}
+		encoded = append(encoded, base58Alphabet[0])
+	}
+	reverse(encoded)
+	return string(encoded)
+}
+
+func base58Decode(input string) ([]byte, error) {
+	result := big.NewInt(0)
+	base := big.NewInt(58)
+
+	for i := 0; i < len(input); i++ {
+		idx := bytes.IndexByte(base58Alphabet, input[i])
+		if idx < 0 {
+			return nil, merrors.InvalidArgument("invalid base58 address")
+		}
+		result.Mul(result, base)
+		result.Add(result, big.NewInt(int64(idx)))
+	}
+
+	decoded := result.Bytes()
+	zeroCount := 0
+	for zeroCount < len(input) && input[zeroCount] == base58Alphabet[0] {
+		zeroCount++
+	}
+	if zeroCount > 0 {
+		decoded = append(make([]byte, zeroCount), decoded...)
+	}
+	return decoded, nil
+}
+
+func reverse(data []byte) {
+	for i, j := 0, len(data)-1; i < j; i, j = i+1, j-1 {
+		data[i], data[j] = data[j], data[i]
+	}
+}
+
+func isHexString(value string) bool {
+	trimmed := strings.TrimPrefix(strings.TrimSpace(value), tronHexPrefix)
+	if trimmed == "" {
+		return false
+	}
+	for _, r := range trimmed {
+		switch {
+		case r >= '0' && r <= '9':
+		case r >= 'a' && r <= 'f':
+		case r >= 'A' && r <= 'F':
+		default:
+			return false
+		}
+	}
+	return true
+}

api/gateway/chain/internal/service/gateway/driver/tron/driver.go

@@ -0,0 +1,223 @@
+package tron
+
+import (
+	"context"
+
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/tech/sendico/gateway/chain/internal/service/gateway/driver"
+	"github.com/tech/sendico/gateway/chain/internal/service/gateway/driver/evm"
+	"github.com/tech/sendico/gateway/chain/internal/service/gateway/shared"
+	"github.com/tech/sendico/gateway/chain/storage/model"
+	"github.com/tech/sendico/pkg/merrors"
+	"github.com/tech/sendico/pkg/mlogger"
+	moneyv1 "github.com/tech/sendico/pkg/proto/common/money/v1"
+	"go.uber.org/zap"
+)
+
+// Driver implements Tron-specific behavior, including address conversion.
+type Driver struct {
+	logger mlogger.Logger
+}
+
+func New(logger mlogger.Logger) *Driver {
+	return &Driver{logger: logger.Named("tron")}
+}
+
+func (d *Driver) Name() string {
+	return "tron"
+}
+
+func (d *Driver) FormatAddress(address string) (string, error) {
+	d.logger.Debug("Format address", zap.String("address", address))
+	normalized, err := normalizeAddress(address)
+	if err != nil {
+		d.logger.Warn("Format address failed", zap.String("address", address), zap.Error(err))
+	}
+	return normalized, err
+}
+
+func (d *Driver) NormalizeAddress(address string) (string, error) {
+	d.logger.Debug("Normalize address", zap.String("address", address))
+	normalized, err := normalizeAddress(address)
+	if err != nil {
+		d.logger.Warn("normalize address failed", zap.String("address", address), zap.Error(err))
+	}
+	return normalized, err
+}
+
+func (d *Driver) Balance(ctx context.Context, deps driver.Deps, network shared.Network, wallet *model.ManagedWallet) (*moneyv1.Money, error) {
+	if wallet == nil {
+		return nil, merrors.InvalidArgument("wallet is required")
+	}
+	d.logger.Debug("Balance request", zap.String("wallet_ref", wallet.WalletRef), zap.String("network", network.Name))
+	rpcAddr, err := rpcAddress(wallet.DepositAddress)
+	if err != nil {
+		d.logger.Warn("Balance address conversion failed", zap.Error(err),
+			zap.String("wallet_ref", wallet.WalletRef),
+			zap.String("address", wallet.DepositAddress),
+		)
+		return nil, err
+	}
+	driverDeps := deps
+	driverDeps.Logger = d.logger
+	result, err := evm.Balance(ctx, driverDeps, network, wallet, rpcAddr)
+	if err != nil {
+		d.logger.Warn("Balance failed", zap.Error(err),
+			zap.String("wallet_ref", wallet.WalletRef),
+			zap.String("network", network.Name),
+		)
+	} else if result != nil {
+		d.logger.Debug("balance result",
+			zap.String("wallet_ref", wallet.WalletRef),
+			zap.String("network", network.Name),
+			zap.String("amount", result.Amount),
+			zap.String("currency", result.Currency),
+		)
+	}
+	return result, err
+}
+
+func (d *Driver) NativeBalance(ctx context.Context, deps driver.Deps, network shared.Network, wallet *model.ManagedWallet) (*moneyv1.Money, error) {
+	if wallet == nil {
+		return nil, merrors.InvalidArgument("wallet is required")
+	}
+	d.logger.Debug("Native balance request", zap.String("wallet_ref", wallet.WalletRef), zap.String("network", network.Name))
+	rpcAddr, err := rpcAddress(wallet.DepositAddress)
+	if err != nil {
+		d.logger.Warn("Native balance address conversion failed", zap.Error(err),
+			zap.String("wallet_ref", wallet.WalletRef),
+			zap.String("address", wallet.DepositAddress),
+		)
+		return nil, err
+	}
+	driverDeps := deps
+	driverDeps.Logger = d.logger
+	result, err := evm.NativeBalance(ctx, driverDeps, network, wallet, rpcAddr)
+	if err != nil {
+		d.logger.Warn("Native balance failed", zap.Error(err),
+			zap.String("wallet_ref", wallet.WalletRef),
+			zap.String("network", network.Name),
+		)
+	} else if result != nil {
+		d.logger.Debug("native balance result",
+			zap.String("wallet_ref", wallet.WalletRef),
+			zap.String("network", network.Name),
+			zap.String("amount", result.Amount),
+			zap.String("currency", result.Currency),
+		)
+	}
+	return result, err
+}
+
+func (d *Driver) EstimateFee(ctx context.Context, deps driver.Deps, network shared.Network, wallet *model.ManagedWallet, destination string, amount *moneyv1.Money) (*moneyv1.Money, error) {
+	if wallet == nil {
+		return nil, merrors.InvalidArgument("wallet is required")
+	}
+	d.logger.Debug("Estimate fee request",
+		zap.String("wallet_ref", wallet.WalletRef),
+		zap.String("network", network.Name),
+		zap.String("destination", destination),
+	)
+	rpcFrom, err := rpcAddress(wallet.DepositAddress)
+	if err != nil {
+		d.logger.Warn("Estimate fee address conversion failed", zap.Error(err),
+			zap.String("wallet_ref", wallet.WalletRef),
+			zap.String("address", wallet.DepositAddress),
+		)
+		return nil, err
+	}
+	rpcTo, err := rpcAddress(destination)
+	if err != nil {
+		d.logger.Warn("Estimate fee destination conversion failed", zap.Error(err),
+			zap.String("wallet_ref", wallet.WalletRef),
+			zap.String("destination", destination),
+		)
+		return nil, err
+	}
+	driverDeps := deps
+	driverDeps.Logger = d.logger
+	result, err := evm.EstimateFee(ctx, driverDeps, network, wallet, rpcFrom, rpcTo, amount)
+	if err != nil {
+		d.logger.Warn("Estimate fee failed", zap.Error(err),
+			zap.String("wallet_ref", wallet.WalletRef),
+			zap.String("network", network.Name),
+		)
+	} else if result != nil {
+		d.logger.Debug("Estimate fee result",
+			zap.String("wallet_ref", wallet.WalletRef),
+			zap.String("network", network.Name),
+			zap.String("amount", result.Amount),
+			zap.String("currency", result.Currency),
+		)
+	}
+	return result, err
+}
+
+func (d *Driver) SubmitTransfer(ctx context.Context, deps driver.Deps, network shared.Network, transfer *model.Transfer, source *model.ManagedWallet, destination string) (string, error) {
+	if source == nil {
+		return "", merrors.InvalidArgument("source wallet is required")
+	}
+	d.logger.Debug("Submit transfer request",
+		zap.String("transfer_ref", transfer.TransferRef),
+		zap.String("network", network.Name),
+		zap.String("destination", destination),
+	)
+	rpcFrom, err := rpcAddress(source.DepositAddress)
+	if err != nil {
+		d.logger.Warn("Submit transfer address conversion failed", zap.Error(err),
+			zap.String("wallet_ref", source.WalletRef),
+			zap.String("address", source.DepositAddress),
+		)
+		return "", err
+	}
+	rpcTo, err := rpcAddress(destination)
+	if err != nil {
+		d.logger.Warn("Submit transfer destination conversion failed", zap.Error(err),
+			zap.String("transfer_ref", transfer.TransferRef),
+			zap.String("destination", destination),
+		)
+		return "", err
+	}
+	driverDeps := deps
+	driverDeps.Logger = d.logger
+	txHash, err := evm.SubmitTransfer(ctx, driverDeps, network, transfer, source, rpcFrom, rpcTo)
+	if err != nil {
+		d.logger.Warn("submit transfer failed", zap.Error(err),
+			zap.String("transfer_ref", transfer.TransferRef),
+			zap.String("network", network.Name),
+		)
+	} else {
+		d.logger.Debug("Submit transfer result",
+			zap.String("transfer_ref", transfer.TransferRef),
+			zap.String("network", network.Name),
+			zap.String("tx_hash", txHash),
+		)
+	}
+	return txHash, err
+}
+
+func (d *Driver) AwaitConfirmation(ctx context.Context, deps driver.Deps, network shared.Network, txHash string) (*types.Receipt, error) {
+	d.logger.Debug("Awaiting confirmation",
+		zap.String("tx_hash", txHash),
+		zap.String("network", network.Name),
+	)
+	driverDeps := deps
+	driverDeps.Logger = d.logger
+	receipt, err := evm.AwaitConfirmation(ctx, driverDeps, network, txHash)
+	if err != nil {
+		d.logger.Warn("Awaiting of confirmation failed", zap.Error(err),
+			zap.String("tx_hash", txHash),
+			zap.String("network", network.Name),
+		)
+	} else if receipt != nil {
+		d.logger.Debug("Await confirmation result",
+			zap.String("tx_hash", txHash),
+			zap.String("network", network.Name),
+			zap.Uint64("block_number", receipt.BlockNumber.Uint64()),
+			zap.Uint64("status", receipt.Status),
+		)
+	}
+	return receipt, err
+}
+
+var _ driver.Driver = (*Driver)(nil)

api/gateway/chain/internal/service/gateway/driver/tron/gas_topup.go

@@ -0,0 +1,143 @@
+package tron
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/shopspring/decimal"
+	"github.com/tech/sendico/gateway/chain/internal/service/gateway/shared"
+	"github.com/tech/sendico/gateway/chain/storage/model"
+	"github.com/tech/sendico/pkg/merrors"
+	moneyv1 "github.com/tech/sendico/pkg/proto/common/money/v1"
+)
+
+var tronBaseUnitFactor = decimal.NewFromInt(1_000_000)
+
+// GasTopUpDecision captures the applied policy inputs and outputs (in TRX units).
+type GasTopUpDecision struct {
+	CurrentBalanceTRX   decimal.Decimal
+	EstimatedFeeTRX     decimal.Decimal
+	RequiredTRX         decimal.Decimal
+	BufferedRequiredTRX decimal.Decimal
+	MinBalanceTopUpTRX  decimal.Decimal
+	RawTopUpTRX         decimal.Decimal
+	RoundedTopUpTRX     decimal.Decimal
+	TopUpTRX            decimal.Decimal
+	CapHit              bool
+	OperationType       string
+}
+
+// ComputeGasTopUp applies the network policy to decide a TRX top-up amount.
+func ComputeGasTopUp(network shared.Network, wallet *model.ManagedWallet, estimatedFee *moneyv1.Money, currentBalance *moneyv1.Money) (*moneyv1.Money, GasTopUpDecision, error) {
+	decision := GasTopUpDecision{}
+	if wallet == nil {
+		return nil, decision, merrors.InvalidArgument("wallet is required")
+	}
+	if estimatedFee == nil || strings.TrimSpace(estimatedFee.GetAmount()) == "" || strings.TrimSpace(estimatedFee.GetCurrency()) == "" {
+		return nil, decision, merrors.InvalidArgument("estimated fee is required")
+	}
+	if currentBalance == nil || strings.TrimSpace(currentBalance.GetAmount()) == "" || strings.TrimSpace(currentBalance.GetCurrency()) == "" {
+		return nil, decision, merrors.InvalidArgument("current native balance is required")
+	}
+	if network.GasTopUpPolicy == nil {
+		return nil, decision, merrors.InvalidArgument("gas top-up policy is not configured")
+	}
+
+	nativeCurrency := strings.TrimSpace(network.NativeToken)
+	if nativeCurrency == "" {
+		nativeCurrency = strings.ToUpper(strings.TrimSpace(network.Name))
+	}
+	if !strings.EqualFold(nativeCurrency, estimatedFee.GetCurrency()) {
+		return nil, decision, merrors.InvalidArgument(fmt.Sprintf("estimated fee currency mismatch (expected %s)", nativeCurrency))
+	}
+	if !strings.EqualFold(nativeCurrency, currentBalance.GetCurrency()) {
+		return nil, decision, merrors.InvalidArgument(fmt.Sprintf("native balance currency mismatch (expected %s)", nativeCurrency))
+	}
+
+	estimatedTRX, err := tronToTRX(estimatedFee)
+	if err != nil {
+		return nil, decision, err
+	}
+	currentTRX, err := tronToTRX(currentBalance)
+	if err != nil {
+		return nil, decision, err
+	}
+
+	isContract := strings.TrimSpace(wallet.ContractAddress) != ""
+	rule, ok := network.GasTopUpPolicy.Rule(isContract)
+	if !ok {
+		return nil, decision, merrors.InvalidArgument("gas top-up policy is not configured")
+	}
+	if rule.RoundingUnit.LessThanOrEqual(decimal.Zero) {
+		return nil, decision, merrors.InvalidArgument("gas top-up rounding unit must be > 0")
+	}
+	if rule.MaxTopUp.LessThanOrEqual(decimal.Zero) {
+		return nil, decision, merrors.InvalidArgument("gas top-up max top-up must be > 0")
+	}
+
+	required := estimatedTRX.Sub(currentTRX)
+	if required.IsNegative() {
+		required = decimal.Zero
+	}
+	bufferedRequired := required.Mul(decimal.NewFromInt(1).Add(rule.BufferPercent))
+
+	minBalanceTopUp := rule.MinNativeBalance.Sub(currentTRX)
+	if minBalanceTopUp.IsNegative() {
+		minBalanceTopUp = decimal.Zero
+	}
+
+	rawTopUp := bufferedRequired
+	if minBalanceTopUp.GreaterThan(rawTopUp) {
+		rawTopUp = minBalanceTopUp
+	}
+
+	roundedTopUp := decimal.Zero
+	if rawTopUp.IsPositive() {
+		roundedTopUp = rawTopUp.Div(rule.RoundingUnit).Ceil().Mul(rule.RoundingUnit)
+	}
+
+	topUp := roundedTopUp
+	capHit := false
+	if topUp.GreaterThan(rule.MaxTopUp) {
+		topUp = rule.MaxTopUp
+		capHit = true
+	}
+
+	decision = GasTopUpDecision{
+		CurrentBalanceTRX:   currentTRX,
+		EstimatedFeeTRX:     estimatedTRX,
+		RequiredTRX:         required,
+		BufferedRequiredTRX: bufferedRequired,
+		MinBalanceTopUpTRX:  minBalanceTopUp,
+		RawTopUpTRX:         rawTopUp,
+		RoundedTopUpTRX:     roundedTopUp,
+		TopUpTRX:            topUp,
+		CapHit:              capHit,
+		OperationType:       operationType(isContract),
+	}
+
+	if !topUp.IsPositive() {
+		return nil, decision, nil
+	}
+
+	baseUnits := topUp.Mul(tronBaseUnitFactor).Ceil().Truncate(0)
+	return &moneyv1.Money{
+		Currency: strings.ToUpper(nativeCurrency),
+		Amount:   baseUnits.StringFixed(0),
+	}, decision, nil
+}
+
+func tronToTRX(amount *moneyv1.Money) (decimal.Decimal, error) {
+	value, err := decimal.NewFromString(strings.TrimSpace(amount.GetAmount()))
+	if err != nil {
+		return decimal.Zero, err
+	}
+	return value.Div(tronBaseUnitFactor), nil
+}
+
+func operationType(contract bool) string {
+	if contract {
+		return "trc20"
+	}
+	return "native"
+}

api/gateway/chain/internal/service/gateway/driver/tron/gas_topup_test.go

@@ -0,0 +1,147 @@
+package tron
+
+import (
+	"testing"
+
+	"github.com/shopspring/decimal"
+	"github.com/stretchr/testify/require"
+	"github.com/tech/sendico/gateway/chain/internal/service/gateway/shared"
+	"github.com/tech/sendico/gateway/chain/storage/model"
+	moneyv1 "github.com/tech/sendico/pkg/proto/common/money/v1"
+)
+
+func TestComputeGasTopUp_BalanceSufficient(t *testing.T) {
+	network := tronNetwork(defaultPolicy())
+	wallet := &model.ManagedWallet{}
+
+	topUp, decision, err := ComputeGasTopUp(network, wallet, tronMoney("5"), tronMoney("30"))
+	require.NoError(t, err)
+	require.Nil(t, topUp)
+	require.True(t, decision.TopUpTRX.IsZero())
+}
+
+func TestComputeGasTopUp_BufferedRequired(t *testing.T) {
+	network := tronNetwork(defaultPolicy())
+	wallet := &model.ManagedWallet{}
+
+	topUp, decision, err := ComputeGasTopUp(network, wallet, tronMoney("50"), tronMoney("10"))
+	require.NoError(t, err)
+	require.NotNil(t, topUp)
+	require.Equal(t, "46000000", topUp.GetAmount())
+	require.Equal(t, "TRX", topUp.GetCurrency())
+	require.Equal(t, "46", decision.TopUpTRX.String())
+}
+
+func TestComputeGasTopUp_MinBalanceBinding(t *testing.T) {
+	network := tronNetwork(defaultPolicy())
+	wallet := &model.ManagedWallet{}
+
+	topUp, decision, err := ComputeGasTopUp(network, wallet, tronMoney("5"), tronMoney("1"))
+	require.NoError(t, err)
+	require.NotNil(t, topUp)
+	require.Equal(t, "19000000", topUp.GetAmount())
+	require.Equal(t, "19", decision.TopUpTRX.String())
+}
+
+func TestComputeGasTopUp_RoundsUp(t *testing.T) {
+	policy := shared.GasTopUpPolicy{
+		Default: shared.GasTopUpRule{
+			BufferPercent:    decimal.NewFromFloat(0),
+			MinNativeBalance: decimal.NewFromFloat(0),
+			RoundingUnit:     decimal.NewFromFloat(1),
+			MaxTopUp:         decimal.NewFromFloat(100),
+		},
+	}
+	network := tronNetwork(&policy)
+	wallet := &model.ManagedWallet{}
+
+	topUp, decision, err := ComputeGasTopUp(network, wallet, tronMoney("1.1"), tronMoney("0"))
+	require.NoError(t, err)
+	require.NotNil(t, topUp)
+	require.Equal(t, "2000000", topUp.GetAmount())
+	require.Equal(t, "2", decision.TopUpTRX.String())
+}
+
+func TestComputeGasTopUp_CapHit(t *testing.T) {
+	policy := shared.GasTopUpPolicy{
+		Default: shared.GasTopUpRule{
+			BufferPercent:    decimal.NewFromFloat(0),
+			MinNativeBalance: decimal.NewFromFloat(0),
+			RoundingUnit:     decimal.NewFromFloat(1),
+			MaxTopUp:         decimal.NewFromFloat(10),
+		},
+	}
+	network := tronNetwork(&policy)
+	wallet := &model.ManagedWallet{}
+
+	topUp, decision, err := ComputeGasTopUp(network, wallet, tronMoney("100"), tronMoney("0"))
+	require.NoError(t, err)
+	require.NotNil(t, topUp)
+	require.Equal(t, "10000000", topUp.GetAmount())
+	require.True(t, decision.CapHit)
+}
+
+func TestComputeGasTopUp_MinBalanceWhenRequiredZero(t *testing.T) {
+	network := tronNetwork(defaultPolicy())
+	wallet := &model.ManagedWallet{}
+
+	topUp, decision, err := ComputeGasTopUp(network, wallet, tronMoney("0"), tronMoney("5"))
+	require.NoError(t, err)
+	require.NotNil(t, topUp)
+	require.Equal(t, "15000000", topUp.GetAmount())
+	require.Equal(t, "15", decision.TopUpTRX.String())
+}
+
+func TestComputeGasTopUp_ContractPolicyOverride(t *testing.T) {
+	policy := shared.GasTopUpPolicy{
+		Default: shared.GasTopUpRule{
+			BufferPercent:    decimal.NewFromFloat(0.1),
+			MinNativeBalance: decimal.NewFromFloat(10),
+			RoundingUnit:     decimal.NewFromFloat(1),
+			MaxTopUp:         decimal.NewFromFloat(100),
+		},
+		Contract: &shared.GasTopUpRule{
+			BufferPercent:    decimal.NewFromFloat(0.5),
+			MinNativeBalance: decimal.NewFromFloat(5),
+			RoundingUnit:     decimal.NewFromFloat(1),
+			MaxTopUp:         decimal.NewFromFloat(100),
+		},
+	}
+	network := tronNetwork(&policy)
+	wallet := &model.ManagedWallet{ContractAddress: "0xcontract"}
+
+	topUp, decision, err := ComputeGasTopUp(network, wallet, tronMoney("10"), tronMoney("0"))
+	require.NoError(t, err)
+	require.NotNil(t, topUp)
+	require.Equal(t, "15000000", topUp.GetAmount())
+	require.Equal(t, "15", decision.TopUpTRX.String())
+	require.Equal(t, "trc20", decision.OperationType)
+}
+
+func defaultPolicy() *shared.GasTopUpPolicy {
+	return &shared.GasTopUpPolicy{
+		Default: shared.GasTopUpRule{
+			BufferPercent:    decimal.NewFromFloat(0.15),
+			MinNativeBalance: decimal.NewFromFloat(20),
+			RoundingUnit:     decimal.NewFromFloat(1),
+			MaxTopUp:         decimal.NewFromFloat(500),
+		},
+	}
+}
+
+func tronNetwork(policy *shared.GasTopUpPolicy) shared.Network {
+	return shared.Network{
+		Name:           "tron_mainnet",
+		NativeToken:    "TRX",
+		GasTopUpPolicy: policy,
+	}
+}
+
+func tronMoney(trx string) *moneyv1.Money {
+	value, _ := decimal.NewFromString(trx)
+	baseUnits := value.Mul(tronBaseUnitFactor).Truncate(0)
+	return &moneyv1.Money{
+		Currency: "TRX",
+		Amount:   baseUnits.StringFixed(0),
+	}
+}

api/gateway/chain/internal/service/gateway/drivers/registry.go

@@ -0,0 +1,74 @@
+package drivers
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/tech/sendico/gateway/chain/internal/service/gateway/driver"
+	"github.com/tech/sendico/gateway/chain/internal/service/gateway/driver/arbitrum"
+	"github.com/tech/sendico/gateway/chain/internal/service/gateway/driver/ethereum"
+	"github.com/tech/sendico/gateway/chain/internal/service/gateway/driver/tron"
+	"github.com/tech/sendico/gateway/chain/internal/service/gateway/shared"
+	"github.com/tech/sendico/pkg/merrors"
+	"github.com/tech/sendico/pkg/mlogger"
+	"go.uber.org/zap"
+)
+
+// Registry maps configured network keys to chain drivers.
+type Registry struct {
+	byNetwork map[string]driver.Driver
+}
+
+// NewRegistry selects drivers for the configured networks.
+func NewRegistry(logger mlogger.Logger, networks []shared.Network) (*Registry, error) {
+	if logger == nil {
+		return nil, merrors.InvalidArgument("driver registry: logger is required")
+	}
+	result := &Registry{byNetwork: map[string]driver.Driver{}}
+	for _, network := range networks {
+		name := strings.ToLower(strings.TrimSpace(network.Name))
+		if name == "" {
+			continue
+		}
+		chainDriver, err := resolveDriver(logger, name)
+		if err != nil {
+			logger.Error("unsupported chain driver", zap.String("network", name), zap.Error(err))
+			return nil, err
+		}
+		result.byNetwork[name] = chainDriver
+	}
+	if len(result.byNetwork) == 0 {
+		return nil, merrors.InvalidArgument("driver registry: no supported networks configured")
+	}
+	logger.Info("chain drivers configured", zap.Int("count", len(result.byNetwork)))
+	return result, nil
+}
+
+// Driver resolves a driver for the provided network key.
+func (r *Registry) Driver(network string) (driver.Driver, error) {
+	if r == nil || len(r.byNetwork) == 0 {
+		return nil, merrors.Internal("driver registry is not configured")
+	}
+	key := strings.ToLower(strings.TrimSpace(network))
+	if key == "" {
+		return nil, merrors.InvalidArgument("network is required")
+	}
+	chainDriver, ok := r.byNetwork[key]
+	if !ok {
+		return nil, merrors.InvalidArgument(fmt.Sprintf("unsupported chain network %s", key))
+	}
+	return chainDriver, nil
+}
+
+func resolveDriver(logger mlogger.Logger, network string) (driver.Driver, error) {
+	switch {
+	case strings.HasPrefix(network, "tron"):
+		return tron.New(logger), nil
+	case strings.HasPrefix(network, "arbitrum"):
+		return arbitrum.New(logger), nil
+	case strings.HasPrefix(network, "ethereum"):
+		return ethereum.New(logger), nil
+	default:
+		return nil, merrors.InvalidArgument("unsupported chain network " + network)
+	}
+}

api/gateway/chain/internal/service/gateway/executor.go

@@ -5,15 +5,15 @@ import (
 	"errors"
 	"math/big"
 	"strings"
-	"sync"
 	"time"
 
 	"github.com/ethereum/go-ethereum"
 	"github.com/ethereum/go-ethereum/accounts/abi"
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/core/types"
-	"github.com/ethereum/go-ethereum/ethclient"
+	"github.com/ethereum/go-ethereum/rpc"
 	"github.com/shopspring/decimal"
+	"github.com/tech/sendico/gateway/chain/internal/service/gateway/rpcclient"
 	"github.com/tech/sendico/gateway/chain/internal/service/gateway/shared"
 	"go.uber.org/zap"
 
@@ -30,11 +30,11 @@ type TransferExecutor interface {
 }
 
 // NewOnChainExecutor constructs a TransferExecutor that talks to an EVM-compatible chain.
-func NewOnChainExecutor(logger mlogger.Logger, keyManager keymanager.Manager) TransferExecutor {
+func NewOnChainExecutor(logger mlogger.Logger, keyManager keymanager.Manager, clients *rpcclient.Clients) TransferExecutor {
 	return &onChainExecutor{
 		logger:     logger.Named("executor"),
 		keyManager: keyManager,
-		clients:    map[string]*ethclient.Client{},
+		clients:    clients,
 	}
 }
 
@@ -42,34 +42,33 @@ type onChainExecutor struct {
 	logger     mlogger.Logger
 	keyManager keymanager.Manager
 
-	mu      sync.Mutex
-	clients map[string]*ethclient.Client
+	clients *rpcclient.Clients
 }
 
 func (o *onChainExecutor) SubmitTransfer(ctx context.Context, transfer *model.Transfer, source *model.ManagedWallet, destinationAddress string, network shared.Network) (string, error) {
 	if o.keyManager == nil {
-		o.logger.Error("key manager not configured")
+		o.logger.Warn("key manager not configured")
 		return "", executorInternal("key manager is not configured", nil)
 	}
 	rpcURL := strings.TrimSpace(network.RPCURL)
 	if rpcURL == "" {
-		o.logger.Error("network rpc url missing", zap.String("network", network.Name))
+		o.logger.Warn("network rpc url missing", zap.String("network", network.Name))
 		return "", executorInvalid("network rpc url is not configured")
 	}
 	if source == nil || transfer == nil {
-		o.logger.Error("transfer context missing")
+		o.logger.Warn("transfer context missing")
 		return "", executorInvalid("transfer context missing")
 	}
 	if strings.TrimSpace(source.KeyReference) == "" {
-		o.logger.Error("source wallet missing key reference", zap.String("wallet_ref", source.WalletRef))
+		o.logger.Warn("source wallet missing key reference", zap.String("wallet_ref", source.WalletRef))
 		return "", executorInvalid("source wallet missing key reference")
 	}
 	if strings.TrimSpace(source.DepositAddress) == "" {
-		o.logger.Error("source wallet missing deposit address", zap.String("wallet_ref", source.WalletRef))
+		o.logger.Warn("source wallet missing deposit address", zap.String("wallet_ref", source.WalletRef))
 		return "", executorInvalid("source wallet missing deposit address")
 	}
 	if !common.IsHexAddress(destinationAddress) {
-		o.logger.Error("invalid destination address", zap.String("transfer_ref", transfer.TransferRef), zap.String("address", destinationAddress))
+		o.logger.Warn("invalid destination address", zap.String("transfer_ref", transfer.TransferRef), zap.String("address", destinationAddress))
 		return "", executorInvalid("invalid destination address " + destinationAddress)
 	}
 
@@ -80,11 +79,15 @@ func (o *onChainExecutor) SubmitTransfer(ctx context.Context, transfer *model.Tr
 		zap.String("destination", strings.ToLower(destinationAddress)),
 	)
 
-	client, err := o.getClient(ctx, rpcURL)
+	client, err := o.clients.Client(network.Name)
+	if err != nil {
+		o.logger.Warn("failed to initialise rpc client", zap.Error(err), zap.String("network", network.Name))
+		return "", err
+	}
+	rpcClient, err := o.clients.RPCClient(network.Name)
 	if err != nil {
 		o.logger.Warn("failed to initialise rpc client",
 			zap.String("network", network.Name),
-			zap.String("rpc_url", rpcURL),
 			zap.Error(err),
 		)
 		return "", err
@@ -98,10 +101,9 @@ func (o *onChainExecutor) SubmitTransfer(ctx context.Context, transfer *model.Tr
 
 	nonce, err := client.PendingNonceAt(ctx, sourceAddress)
 	if err != nil {
-		o.logger.Warn("failed to fetch nonce",
+		o.logger.Warn("failed to fetch nonce", zap.Error(err),
 			zap.String("transfer_ref", transfer.TransferRef),
 			zap.String("wallet_ref", source.WalletRef),
-			zap.Error(err),
 		)
 		return "", executorInternal("failed to fetch nonce", err)
 	}
@@ -135,12 +137,11 @@ func (o *onChainExecutor) SubmitTransfer(ctx context.Context, transfer *model.Tr
 	}
 	tokenAddress := common.HexToAddress(transfer.ContractAddress)
 
-	decimals, err := erc20Decimals(ctx, client, tokenAddress)
+	decimals, err := erc20Decimals(ctx, rpcClient, tokenAddress)
 	if err != nil {
-		o.logger.Warn("failed to read token decimals",
+		o.logger.Warn("failed to read token decimals", zap.Error(err),
 			zap.String("transfer_ref", transfer.TransferRef),
 			zap.String("contract", transfer.ContractAddress),
-			zap.Error(err),
 		)
 		return "", err
 	}
@@ -152,10 +153,9 @@ func (o *onChainExecutor) SubmitTransfer(ctx context.Context, transfer *model.Tr
 	}
 	amountInt, err := toBaseUnits(amount.Amount, decimals)
 	if err != nil {
-		o.logger.Warn("failed to convert amount to base units",
+		o.logger.Warn("failed to convert amount to base units", zap.Error(err),
 			zap.String("transfer_ref", transfer.TransferRef),
 			zap.String("amount", amount.Amount),
-			zap.Error(err),
 		)
 		return "", err
 	}
@@ -188,18 +188,16 @@ func (o *onChainExecutor) SubmitTransfer(ctx context.Context, transfer *model.Tr
 
 	signedTx, err := o.keyManager.SignTransaction(ctx, source.KeyReference, tx, chainID)
 	if err != nil {
-		o.logger.Warn("failed to sign transaction",
+		o.logger.Warn("failed to sign transaction", zap.Error(err),
 			zap.String("transfer_ref", transfer.TransferRef),
 			zap.String("wallet_ref", source.WalletRef),
-			zap.Error(err),
 		)
 		return "", err
 	}
 
 	if err := client.SendTransaction(ctx, signedTx); err != nil {
-		o.logger.Warn("failed to send transaction",
+		o.logger.Warn("failed to send transaction", zap.Error(err),
 			zap.String("transfer_ref", transfer.TransferRef),
-			zap.Error(err),
 		)
 		return "", executorInternal("failed to send transaction", err)
 	}
@@ -214,30 +212,6 @@ func (o *onChainExecutor) SubmitTransfer(ctx context.Context, transfer *model.Tr
 	return txHash, nil
 }
 
-func (o *onChainExecutor) getClient(ctx context.Context, rpcURL string) (*ethclient.Client, error) {
-	o.mu.Lock()
-	client, ok := o.clients[rpcURL]
-	o.mu.Unlock()
-	if ok {
-		return client, nil
-	}
-
-	c, err := ethclient.DialContext(ctx, rpcURL)
-	if err != nil {
-		return nil, executorInternal("failed to connect to rpc "+rpcURL, err)
-	}
-
-	o.mu.Lock()
-	defer o.mu.Unlock()
-	if existing, ok := o.clients[rpcURL]; ok {
-		// Another routine initialised it in the meantime; prefer the existing client and close the new one.
-		c.Close()
-		return existing, nil
-	}
-	o.clients[rpcURL] = c
-	return c, nil
-}
-
 func (o *onChainExecutor) AwaitConfirmation(ctx context.Context, network shared.Network, txHash string) (*types.Receipt, error) {
 	if strings.TrimSpace(txHash) == "" {
 		o.logger.Warn("missing transaction hash for confirmation", zap.String("network", network.Name))
@@ -249,7 +223,7 @@ func (o *onChainExecutor) AwaitConfirmation(ctx context.Context, network shared.
 		return nil, executorInvalid("network rpc url is not configured")
 	}
 
-	client, err := o.getClient(ctx, rpcURL)
+	client, err := o.clients.Client(network.Name)
 	if err != nil {
 		return nil, err
 	}
@@ -331,31 +305,20 @@ const erc20ABIJSON = `
 	}
 ]`
 
-func erc20Decimals(ctx context.Context, client *ethclient.Client, token common.Address) (uint8, error) {
-	callData, err := erc20ABI.Pack("decimals")
-	if err != nil {
-		return 0, executorInternal("failed to encode decimals call", err)
+func erc20Decimals(ctx context.Context, client *rpc.Client, token common.Address) (uint8, error) {
+	call := map[string]string{
+		"to":   strings.ToLower(token.Hex()),
+		"data": "0x313ce567",
 	}
-	msg := ethereum.CallMsg{
-		To:   &token,
-		Data: callData,
-	}
-	output, err := client.CallContract(ctx, msg, nil)
-	if err != nil {
+	var hexResp string
+	if err := client.CallContext(ctx, &hexResp, "eth_call", call, "latest"); err != nil {
 		return 0, executorInternal("decimals call failed", err)
 	}
-	values, err := erc20ABI.Unpack("decimals", output)
+	val, err := shared.DecodeHexUint8(hexResp)
 	if err != nil {
-		return 0, executorInternal("failed to unpack decimals", err)
+		return 0, executorInternal("decimals decode failed", err)
 	}
-	if len(values) == 0 {
-		return 0, executorInternal("decimals call returned no data", nil)
-	}
-	decimals, ok := values[0].(uint8)
-	if !ok {
-		return 0, executorInternal("decimals call returned unexpected type", nil)
-	}
-	return decimals, nil
+	return val, nil
 }
 
 func toBaseUnits(amount string, decimals uint8) (*big.Int, error) {

api/gateway/chain/internal/service/gateway/options.go

@@ -4,6 +4,8 @@ import (
 	"strings"
 
 	"github.com/tech/sendico/gateway/chain/internal/keymanager"
+	"github.com/tech/sendico/gateway/chain/internal/service/gateway/drivers"
+	"github.com/tech/sendico/gateway/chain/internal/service/gateway/rpcclient"
 	"github.com/tech/sendico/gateway/chain/internal/service/gateway/shared"
 	clockpkg "github.com/tech/sendico/pkg/clock"
 )
@@ -18,10 +20,10 @@ func WithKeyManager(manager keymanager.Manager) Option {
 	}
 }
 
-// WithTransferExecutor configures the executor responsible for on-chain submissions.
-func WithTransferExecutor(executor TransferExecutor) Option {
+// WithRPCClients configures pre-initialised RPC clients.
+func WithRPCClients(clients *rpcclient.Clients) Option {
 	return func(s *Service) {
-		s.executor = executor
+		s.rpcClients = clients
 	}
 }
 
@@ -59,6 +61,13 @@ func WithServiceWallet(wallet shared.ServiceWallet) Option {
 	}
 }
 
+// WithDriverRegistry configures the chain driver registry.
+func WithDriverRegistry(registry *drivers.Registry) Option {
+	return func(s *Service) {
+		s.drivers = registry
+	}
+}
+
 // WithClock overrides the service clock.
 func WithClock(clk clockpkg.Clock) Option {
 	return func(s *Service) {

api/gateway/chain/internal/service/gateway/rpcclient/clients.go

@@ -0,0 +1,196 @@
+package rpcclient
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"net/http"
+	"strings"
+	"time"
+
+	"github.com/ethereum/go-ethereum/ethclient"
+	"github.com/ethereum/go-ethereum/rpc"
+	"github.com/tech/sendico/gateway/chain/internal/service/gateway/shared"
+	"github.com/tech/sendico/pkg/merrors"
+	"github.com/tech/sendico/pkg/mlogger"
+	"go.uber.org/zap"
+)
+
+// Clients holds pre-initialised RPC clients keyed by network name.
+type Clients struct {
+	logger  mlogger.Logger
+	clients map[string]clientEntry
+}
+
+type clientEntry struct {
+	eth *ethclient.Client
+	rpc *rpc.Client
+}
+
+// Prepare dials all configured networks up front and returns a ready-to-use client set.
+func Prepare(ctx context.Context, logger mlogger.Logger, networks []shared.Network) (*Clients, error) {
+	if logger == nil {
+		return nil, merrors.Internal("rpc clients: logger is required")
+	}
+	clientLogger := logger.Named("rpc_client")
+	result := &Clients{
+		logger:  clientLogger,
+		clients: make(map[string]clientEntry),
+	}
+
+	for _, network := range networks {
+		name := strings.ToLower(strings.TrimSpace(network.Name))
+		rpcURL := strings.TrimSpace(network.RPCURL)
+		if name == "" {
+			clientLogger.Warn("Skipping network with empty name during rpc client preparation")
+			continue
+		}
+		if rpcURL == "" {
+			result.Close()
+			err := merrors.InvalidArgument(fmt.Sprintf("rpc url not configured for network %s", name))
+			clientLogger.Warn("rpc url missing", zap.String("network", name))
+			return nil, err
+		}
+
+		fields := []zap.Field{
+			zap.String("network", name),
+		}
+		clientLogger.Info("initialising rpc client", fields...)
+
+		dialCtx, cancel := context.WithTimeout(ctx, 15*time.Second)
+		httpClient := &http.Client{
+			Transport: &loggingRoundTripper{
+				logger:   clientLogger,
+				network:  name,
+				endpoint: rpcURL,
+				base:     http.DefaultTransport,
+			},
+		}
+		rpcCli, err := rpc.DialOptions(dialCtx, rpcURL, rpc.WithHTTPClient(httpClient))
+		cancel()
+		if err != nil {
+			result.Close()
+			clientLogger.Warn("failed to dial rpc endpoint", append(fields, zap.Error(err))...)
+			return nil, merrors.Internal(fmt.Sprintf("rpc dial failed for %s: %s", name, err.Error()))
+		}
+		client := ethclient.NewClient(rpcCli)
+		result.clients[name] = clientEntry{
+			eth: client,
+			rpc: rpcCli,
+		}
+		clientLogger.Info("rpc client ready", fields...)
+	}
+
+	if len(result.clients) == 0 {
+		clientLogger.Warn("No rpc clients were initialised")
+		return nil, merrors.InvalidArgument("no rpc clients initialised")
+	} else {
+		clientLogger.Info("RPC clients initialised", zap.Int("count", len(result.clients)))
+	}
+
+	return result, nil
+}
+
+// Client returns a prepared client for the given network name.
+func (c *Clients) Client(network string) (*ethclient.Client, error) {
+	if c == nil {
+		return nil, merrors.Internal("rpc clients not initialised")
+	}
+	name := strings.ToLower(strings.TrimSpace(network))
+	entry, ok := c.clients[name]
+	if !ok || entry.eth == nil {
+		return nil, merrors.InvalidArgument(fmt.Sprintf("rpc client not configured for network %s", name))
+	}
+	return entry.eth, nil
+}
+
+// RPCClient returns the raw RPC client for low-level calls.
+func (c *Clients) RPCClient(network string) (*rpc.Client, error) {
+	if c == nil {
+		return nil, merrors.Internal("rpc clients not initialised")
+	}
+	name := strings.ToLower(strings.TrimSpace(network))
+	entry, ok := c.clients[name]
+	if !ok || entry.rpc == nil {
+		return nil, merrors.InvalidArgument(fmt.Sprintf("rpc client not configured for network %s", name))
+	}
+	return entry.rpc, nil
+}
+
+// Close tears down all RPC clients, logging each close.
+func (c *Clients) Close() {
+	if c == nil {
+		return
+	}
+	for name, entry := range c.clients {
+		if entry.rpc != nil {
+			entry.rpc.Close()
+		} else if entry.eth != nil {
+			entry.eth.Close()
+		}
+		if c.logger != nil {
+			c.logger.Info("rpc client closed", zap.String("network", name))
+		}
+	}
+}
+
+type loggingRoundTripper struct {
+	logger   mlogger.Logger
+	network  string
+	endpoint string
+	base     http.RoundTripper
+}
+
+func (l *loggingRoundTripper) RoundTrip(req *http.Request) (*http.Response, error) {
+	if l.base == nil {
+		l.base = http.DefaultTransport
+	}
+
+	var reqBody []byte
+	if req.Body != nil {
+		raw, _ := io.ReadAll(req.Body)
+		reqBody = raw
+		req.Body = io.NopCloser(strings.NewReader(string(raw)))
+	}
+
+	fields := []zap.Field{
+		zap.String("network", l.network),
+		zap.String("rpc_endpoint", l.endpoint),
+	}
+	if len(reqBody) > 0 {
+		fields = append(fields, zap.String("rpc_request", truncate(string(reqBody), 2048)))
+	}
+	l.logger.Debug("rpc request", fields...)
+
+	resp, err := l.base.RoundTrip(req)
+	if err != nil {
+		l.logger.Warn("rpc http request failed", append(fields, zap.Error(err))...)
+		return nil, err
+	}
+
+	bodyBytes, _ := io.ReadAll(resp.Body)
+	resp.Body.Close()
+	resp.Body = io.NopCloser(strings.NewReader(string(bodyBytes)))
+
+	respFields := append(fields,
+		zap.Int("status_code", resp.StatusCode),
+	)
+	if len(bodyBytes) > 0 {
+		respFields = append(respFields, zap.String("rpc_response", truncate(string(bodyBytes), 2048)))
+	}
+	if resp.StatusCode >= 400 {
+		l.logger.Warn("RPC response error", respFields...)
+	}
+
+	return resp, nil
+}
+
+func truncate(s string, max int) string {
+	if len(s) <= max {
+		return s
+	}
+	if max <= 3 {
+		return s[:max]
+	}
+	return s[:max-3] + "..."
+}

api/gateway/chain/internal/service/gateway/rpcclient/registry.go

@@ -0,0 +1,54 @@
+package rpcclient
+
+import (
+	"strings"
+
+	"github.com/ethereum/go-ethereum/ethclient"
+	"github.com/ethereum/go-ethereum/rpc"
+	"github.com/tech/sendico/gateway/chain/internal/service/gateway/shared"
+	"github.com/tech/sendico/pkg/merrors"
+)
+
+// Registry binds static network metadata with prepared RPC clients.
+type Registry struct {
+	networks map[string]shared.Network
+	clients  *Clients
+}
+
+// NewRegistry constructs a registry keyed by lower-cased network name.
+func NewRegistry(networks map[string]shared.Network, clients *Clients) *Registry {
+	return &Registry{
+		networks: networks,
+		clients:  clients,
+	}
+}
+
+// Network fetches network metadata by key (case-insensitive).
+func (r *Registry) Network(key string) (shared.Network, bool) {
+	if r == nil || len(r.networks) == 0 {
+		return shared.Network{}, false
+	}
+	n, ok := r.networks[strings.ToLower(strings.TrimSpace(key))]
+	return n, ok
+}
+
+// Client returns the prepared RPC client for the given network name.
+func (r *Registry) Client(key string) (*ethclient.Client, error) {
+	if r == nil || r.clients == nil {
+		return nil, merrors.Internal("rpc clients not initialised")
+	}
+	return r.clients.Client(strings.ToLower(strings.TrimSpace(key)))
+}
+
+// RPCClient returns the raw RPC client for low-level calls.
+func (r *Registry) RPCClient(key string) (*rpc.Client, error) {
+	if r == nil || r.clients == nil {
+		return nil, merrors.Internal("rpc clients not initialised")
+	}
+	return r.clients.RPCClient(strings.ToLower(strings.TrimSpace(key)))
+}
+
+// Networks exposes the registry map for iteration when needed.
+func (r *Registry) Networks() map[string]shared.Network {
+	return r.networks
+}

api/gateway/chain/internal/service/gateway/service.go

@@ -7,6 +7,8 @@ import (
 	"github.com/tech/sendico/gateway/chain/internal/service/gateway/commands"
 	"github.com/tech/sendico/gateway/chain/internal/service/gateway/commands/transfer"
 	"github.com/tech/sendico/gateway/chain/internal/service/gateway/commands/wallet"
+	"github.com/tech/sendico/gateway/chain/internal/service/gateway/drivers"
+	"github.com/tech/sendico/gateway/chain/internal/service/gateway/rpcclient"
 	"github.com/tech/sendico/gateway/chain/internal/service/gateway/shared"
 	"github.com/tech/sendico/gateway/chain/storage"
 	"github.com/tech/sendico/pkg/api/routers"
@@ -38,11 +40,13 @@ type Service struct {
 
 	settings CacheSettings
 
-	networks      map[string]shared.Network
-	serviceWallet shared.ServiceWallet
-	keyManager    keymanager.Manager
-	executor      TransferExecutor
-	commands      commands.Registry
+	networks        map[string]shared.Network
+	serviceWallet   shared.ServiceWallet
+	keyManager      keymanager.Manager
+	rpcClients      *rpcclient.Clients
+	networkRegistry *rpcclient.Registry
+	drivers         *drivers.Registry
+	commands        commands.Registry
 
 	chainv1.UnimplementedChainGatewayServiceServer
 }
@@ -73,6 +77,7 @@ func NewService(logger mlogger.Logger, repo storage.Repository, producer msg.Pro
 		svc.networks = map[string]shared.Network{}
 	}
 	svc.settings = svc.settings.withDefaults()
+	svc.networkRegistry = rpcclient.NewRegistry(svc.networks, svc.rpcClients)
 
 	svc.commands = commands.NewRegistry(commands.RegistryDeps{
 		Wallet:   commandsWalletDeps(svc),
@@ -121,6 +126,14 @@ func (s *Service) EstimateTransferFee(ctx context.Context, req *chainv1.Estimate
 	return executeUnary(ctx, s, "EstimateTransferFee", s.commands.EstimateTransfer.Execute, req)
 }
 
+func (s *Service) ComputeGasTopUp(ctx context.Context, req *chainv1.ComputeGasTopUpRequest) (*chainv1.ComputeGasTopUpResponse, error) {
+	return executeUnary(ctx, s, "ComputeGasTopUp", s.commands.ComputeGasTopUp.Execute, req)
+}
+
+func (s *Service) EnsureGasTopUp(ctx context.Context, req *chainv1.EnsureGasTopUpRequest) (*chainv1.EnsureGasTopUpResponse, error) {
+	return executeUnary(ctx, s, "EnsureGasTopUp", s.commands.EnsureGasTopUp.Execute, req)
+}
+
 func (s *Service) ensureRepository(ctx context.Context) error {
 	if s.storage == nil {
 		return errStorageUnavailable
@@ -131,11 +144,13 @@ func (s *Service) ensureRepository(ctx context.Context) error {
 func commandsWalletDeps(s *Service) wallet.Deps {
 	return wallet.Deps{
 		Logger:           s.logger.Named("command"),
-		Networks:         s.networks,
+		Drivers:          s.drivers,
+		Networks:         s.networkRegistry,
 		KeyManager:       s.keyManager,
 		Storage:          s.storage,
 		Clock:            s.clock,
 		BalanceCacheTTL:  s.settings.walletBalanceCacheTTL(),
+		RPCTimeout:       s.settings.rpcTimeout(),
 		EnsureRepository: s.ensureRepository,
 	}
 }
@@ -143,9 +158,11 @@ func commandsWalletDeps(s *Service) wallet.Deps {
 func commandsTransferDeps(s *Service) transfer.Deps {
 	return transfer.Deps{
 		Logger:           s.logger.Named("transfer_cmd"),
-		Networks:         s.networks,
+		Drivers:          s.drivers,
+		Networks:         s.networkRegistry,
 		Storage:          s.storage,
 		Clock:            s.clock,
+		RPCTimeout:       s.settings.rpcTimeout(),
 		EnsureRepository: s.ensureRepository,
 		LaunchExecution:  s.launchTransferExecution,
 	}

api/gateway/chain/internal/service/gateway/service_test.go

@@ -18,6 +18,7 @@ import (
 	"google.golang.org/grpc/status"
 
 	"github.com/tech/sendico/gateway/chain/internal/keymanager"
+	"github.com/tech/sendico/gateway/chain/internal/service/gateway/drivers"
 	"github.com/tech/sendico/gateway/chain/internal/service/gateway/shared"
 	"github.com/tech/sendico/gateway/chain/storage"
 	"github.com/tech/sendico/gateway/chain/storage/model"
@@ -65,6 +66,25 @@ func TestCreateManagedWallet_Idempotent(t *testing.T) {
 	require.Equal(t, 1, repo.wallets.count())
 }
 
+func TestCreateManagedWallet_NativeTokenWithoutContract(t *testing.T) {
+	svc, _ := newTestService(t)
+	ctx := context.Background()
+
+	resp, err := svc.CreateManagedWallet(ctx, &ichainv1.CreateManagedWalletRequest{
+		IdempotencyKey:  "idem-native",
+		OrganizationRef: "org-1",
+		OwnerRef:        "owner-1",
+		Asset: &ichainv1.Asset{
+			Chain:       ichainv1.ChainNetwork_CHAIN_NETWORK_ETHEREUM_MAINNET,
+			TokenSymbol: "ETH",
+		},
+	})
+	require.NoError(t, err)
+	require.NotNil(t, resp.GetWallet())
+	require.Equal(t, "ETH", resp.GetWallet().GetAsset().GetTokenSymbol())
+	require.Empty(t, resp.GetWallet().GetAsset().GetContractAddress())
+}
+
 func TestSubmitTransfer_ManagedDestination(t *testing.T) {
 	svc, repo := newTestService(t)
 	ctx := context.Background()
@@ -143,6 +163,37 @@ func TestGetWalletBalance_NotFound(t *testing.T) {
 	require.Equal(t, codes.NotFound, st.Code())
 }
 
+func TestGetWalletBalance_ReturnsCachedNativeAvailable(t *testing.T) {
+	svc, repo := newTestService(t)
+	ctx := context.Background()
+
+	createResp, err := svc.CreateManagedWallet(ctx, &ichainv1.CreateManagedWalletRequest{
+		IdempotencyKey:  "idem-balance",
+		OrganizationRef: "org-1",
+		OwnerRef:        "owner-1",
+		Asset: &ichainv1.Asset{
+			Chain:       ichainv1.ChainNetwork_CHAIN_NETWORK_ETHEREUM_MAINNET,
+			TokenSymbol: "USDC",
+		},
+	})
+	require.NoError(t, err)
+	walletRef := createResp.GetWallet().GetWalletRef()
+
+	err = repo.wallets.SaveBalance(ctx, &model.WalletBalance{
+		WalletRef:       walletRef,
+		Available:       &moneyv1.Money{Currency: "USDC", Amount: "25"},
+		NativeAvailable: &moneyv1.Money{Currency: "ETH", Amount: "0.5"},
+		CalculatedAt:    time.Now().UTC(),
+	})
+	require.NoError(t, err)
+
+	resp, err := svc.GetWalletBalance(ctx, &ichainv1.GetWalletBalanceRequest{WalletRef: walletRef})
+	require.NoError(t, err)
+	require.NotNil(t, resp.GetBalance())
+	require.Equal(t, "0.5", resp.GetBalance().GetNativeAvailable().GetAmount())
+	require.Equal(t, "ETH", resp.GetBalance().GetNativeAvailable().GetCurrency())
+}
+
 // ---- in-memory storage implementation ----
 
 type inMemoryRepository struct {
@@ -526,18 +577,23 @@ func sanitizeLimit(requested int32, def, max int64) int64 {
 	return int64(requested)
 }
 
-func newTestService(_ *testing.T) (*Service, *inMemoryRepository) {
+func newTestService(t *testing.T) (*Service, *inMemoryRepository) {
 	repo := newInMemoryRepository()
 	logger := zap.NewNop()
+	networks := []shared.Network{{
+		Name:        "ethereum_mainnet",
+		NativeToken: "ETH",
+		TokenConfigs: []shared.TokenContract{
+			{Symbol: "USDC", ContractAddress: "0xusdc"},
+		},
+	}}
+	driverRegistry, err := drivers.NewRegistry(logger.Named("drivers"), networks)
+	require.NoError(t, err)
 	svc := NewService(logger, repo, nil,
 		WithKeyManager(&fakeKeyManager{}),
-		WithNetworks([]shared.Network{{
-			Name: "ethereum_mainnet",
-			TokenConfigs: []shared.TokenContract{
-				{Symbol: "USDC", ContractAddress: "0xusdc"},
-			},
-		}}),
+		WithNetworks(networks),
 		WithServiceWallet(shared.ServiceWallet{Network: "ethereum_mainnet", Address: "0xservice"}),
+		WithDriverRegistry(driverRegistry),
 	)
 	return svc, repo
 }

api/gateway/chain/internal/service/gateway/settings.go

@@ -3,15 +3,18 @@ package gateway
 import "time"
 
 const defaultWalletBalanceCacheTTL = 120 * time.Second
+const defaultRPCRequestTimeout = 15 * time.Second
 
 // CacheSettings holds tunable gateway behaviour.
 type CacheSettings struct {
 	WalletBalanceCacheTTLSeconds int `yaml:"wallet_balance_ttl_seconds"`
+	RPCRequestTimeoutSeconds     int `yaml:"rpc_request_timeout_seconds"`
 }
 
 func defaultSettings() CacheSettings {
 	return CacheSettings{
 		WalletBalanceCacheTTLSeconds: int(defaultWalletBalanceCacheTTL.Seconds()),
+		RPCRequestTimeoutSeconds:     int(defaultRPCRequestTimeout.Seconds()),
 	}
 }
 
@@ -19,6 +22,9 @@ func (s CacheSettings) withDefaults() CacheSettings {
 	if s.WalletBalanceCacheTTLSeconds <= 0 {
 		s.WalletBalanceCacheTTLSeconds = int(defaultWalletBalanceCacheTTL.Seconds())
 	}
+	if s.RPCRequestTimeoutSeconds <= 0 {
+		s.RPCRequestTimeoutSeconds = int(defaultRPCRequestTimeout.Seconds())
+	}
 	return s
 }
 
@@ -28,3 +34,10 @@ func (s CacheSettings) walletBalanceCacheTTL() time.Duration {
 	}
 	return time.Duration(s.WalletBalanceCacheTTLSeconds) * time.Second
 }
+
+func (s CacheSettings) rpcTimeout() time.Duration {
+	if s.RPCRequestTimeoutSeconds <= 0 {
+		return defaultRPCRequestTimeout
+	}
+	return time.Duration(s.RPCRequestTimeoutSeconds) * time.Second
+}

api/gateway/chain/internal/service/gateway/shared/gas_topup.go

@@ -0,0 +1,32 @@
+package shared
+
+import "github.com/shopspring/decimal"
+
+// GasTopUpRule defines buffer, minimum, rounding, and cap behavior for native gas top-ups.
+type GasTopUpRule struct {
+	BufferPercent    decimal.Decimal
+	MinNativeBalance decimal.Decimal
+	RoundingUnit     decimal.Decimal
+	MaxTopUp         decimal.Decimal
+}
+
+// GasTopUpPolicy captures default and optional overrides for native vs contract transfers.
+type GasTopUpPolicy struct {
+	Default  GasTopUpRule
+	Native   *GasTopUpRule
+	Contract *GasTopUpRule
+}
+
+// Rule selects the policy rule for the transfer type.
+func (p *GasTopUpPolicy) Rule(contractTransfer bool) (GasTopUpRule, bool) {
+	if p == nil {
+		return GasTopUpRule{}, false
+	}
+	if contractTransfer && p.Contract != nil {
+		return *p.Contract, true
+	}
+	if !contractTransfer && p.Native != nil {
+		return *p.Native, true
+	}
+	return p.Default, true
+}

api/gateway/chain/internal/service/gateway/shared/helpers.go

@@ -121,11 +121,12 @@ func TransferStatusToProto(status model.TransferStatus) chainv1.TransferStatus {
 
 // Network describes a supported blockchain network and known token contracts.
 type Network struct {
-	Name         string
-	RPCURL       string
-	ChainID      uint64
-	NativeToken  string
-	TokenConfigs []TokenContract
+	Name           string
+	RPCURL         string
+	ChainID        uint64
+	NativeToken    string
+	TokenConfigs   []TokenContract
+	GasTopUpPolicy *GasTopUpPolicy
 }
 
 // TokenContract captures the metadata needed to work with a specific on-chain token.

api/gateway/chain/internal/service/gateway/shared/hex.go

@@ -0,0 +1,49 @@
+package shared
+
+import (
+	"errors"
+	"math/big"
+	"strings"
+)
+
+var (
+	errHexEmpty      = errors.New("hex value is empty")
+	errHexInvalid    = errors.New("invalid hex number")
+	errHexOutOfRange = errors.New("hex number out of range")
+)
+
+// DecodeHexBig parses a hex string that may include leading zero digits.
+func DecodeHexBig(input string) (*big.Int, error) {
+	trimmed := strings.TrimSpace(input)
+	if trimmed == "" {
+		return nil, errHexEmpty
+	}
+	noPrefix := strings.TrimPrefix(trimmed, "0x")
+	if noPrefix == "" {
+		return nil, errHexEmpty
+	}
+	value := strings.TrimLeft(noPrefix, "0")
+	if value == "" {
+		return big.NewInt(0), nil
+	}
+	val := new(big.Int)
+	if _, ok := val.SetString(value, 16); !ok {
+		return nil, errHexInvalid
+	}
+	return val, nil
+}
+
+// DecodeHexUint8 parses a hex string into uint8, allowing leading zeros.
+func DecodeHexUint8(input string) (uint8, error) {
+	val, err := DecodeHexBig(input)
+	if err != nil {
+		return 0, err
+	}
+	if val == nil {
+		return 0, errHexInvalid
+	}
+	if val.BitLen() > 8 {
+		return 0, errHexOutOfRange
+	}
+	return uint8(val.Uint64()), nil
+}

api/gateway/chain/internal/service/gateway/shared/hex_test.go

@@ -0,0 +1,16 @@
+package shared
+
+import "testing"
+
+func TestDecodeHexUint8_LeadingZeros(t *testing.T) {
+	t.Parallel()
+
+	const resp = "0x0000000000000000000000000000000000000000000000000000000000000006"
+	val, err := DecodeHexUint8(resp)
+	if err != nil {
+		t.Fatalf("DecodeHexUint8 error: %v", err)
+	}
+	if val != 6 {
+		t.Fatalf("DecodeHexUint8 value = %d, want 6", val)
+	}
+}

api/gateway/chain/internal/service/gateway/transfer_execution.go

@@ -7,15 +7,15 @@ import (
 	"time"
 
 	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/tech/sendico/gateway/chain/internal/service/gateway/driver"
+	"github.com/tech/sendico/gateway/chain/internal/service/gateway/shared"
 	"github.com/tech/sendico/gateway/chain/storage/model"
 	"github.com/tech/sendico/pkg/merrors"
 	"go.uber.org/zap"
-
-	"github.com/tech/sendico/gateway/chain/internal/service/gateway/shared"
 )
 
 func (s *Service) launchTransferExecution(transferRef, sourceWalletRef string, network shared.Network) {
-	if s.executor == nil {
+	if s.drivers == nil {
 		return
 	}
 
@@ -24,7 +24,7 @@ func (s *Service) launchTransferExecution(transferRef, sourceWalletRef string, n
 		defer cancel()
 
 		if err := s.executeTransfer(ctx, ref, walletRef, net); err != nil {
-			s.logger.Error("failed to execute transfer", zap.String("transfer_ref", ref), zap.Error(err))
+			s.logger.Warn("failed to execute transfer", zap.String("transfer_ref", ref), zap.Error(err))
 		}
 	}(transferRef, sourceWalletRef, network)
 }
@@ -44,13 +44,20 @@ func (s *Service) executeTransfer(ctx context.Context, transferRef, sourceWallet
 		s.logger.Warn("failed to update transfer status to signing", zap.String("transfer_ref", transferRef), zap.Error(err))
 	}
 
-	destinationAddress, err := s.destinationAddress(ctx, transfer.Destination)
+	driverDeps := s.driverDeps()
+	chainDriver, err := s.driverForNetwork(network.Name)
 	if err != nil {
 		_, _ = s.storage.Transfers().UpdateStatus(ctx, transferRef, model.TransferStatusFailed, err.Error(), "")
 		return err
 	}
 
-	txHash, err := s.executor.SubmitTransfer(ctx, transfer, sourceWallet, destinationAddress, network)
+	destinationAddress, err := s.destinationAddress(ctx, chainDriver, transfer.Destination)
+	if err != nil {
+		_, _ = s.storage.Transfers().UpdateStatus(ctx, transferRef, model.TransferStatusFailed, err.Error(), "")
+		return err
+	}
+
+	txHash, err := chainDriver.SubmitTransfer(ctx, driverDeps, network, transfer, sourceWallet, destinationAddress)
 	if err != nil {
 		_, _ = s.storage.Transfers().UpdateStatus(ctx, transferRef, model.TransferStatusFailed, err.Error(), "")
 		return err
@@ -62,7 +69,7 @@ func (s *Service) executeTransfer(ctx context.Context, transferRef, sourceWallet
 
 	receiptCtx, cancel := context.WithTimeout(ctx, 10*time.Minute)
 	defer cancel()
-	receipt, err := s.executor.AwaitConfirmation(receiptCtx, network, txHash)
+	receipt, err := chainDriver.AwaitConfirmation(receiptCtx, driverDeps, network, txHash)
 	if err != nil {
 		if !errors.Is(err, context.DeadlineExceeded) && !errors.Is(err, context.Canceled) {
 			s.logger.Warn("failed to await transfer confirmation", zap.String("transfer_ref", transferRef), zap.Error(err))
@@ -83,7 +90,7 @@ func (s *Service) executeTransfer(ctx context.Context, transferRef, sourceWallet
 	return nil
 }
 
-func (s *Service) destinationAddress(ctx context.Context, dest model.TransferDestination) (string, error) {
+func (s *Service) destinationAddress(ctx context.Context, chainDriver driver.Driver, dest model.TransferDestination) (string, error) {
 	if ref := strings.TrimSpace(dest.ManagedWalletRef); ref != "" {
 		wallet, err := s.storage.Wallets().Get(ctx, ref)
 		if err != nil {
@@ -92,10 +99,26 @@ func (s *Service) destinationAddress(ctx context.Context, dest model.TransferDes
 		if strings.TrimSpace(wallet.DepositAddress) == "" {
 			return "", merrors.Internal("destination wallet missing deposit address")
 		}
-		return wallet.DepositAddress, nil
+		return chainDriver.NormalizeAddress(wallet.DepositAddress)
 	}
 	if addr := strings.TrimSpace(dest.ExternalAddress); addr != "" {
-		return strings.ToLower(addr), nil
+		return chainDriver.NormalizeAddress(addr)
 	}
 	return "", merrors.InvalidArgument("transfer destination address not resolved")
 }
+
+func (s *Service) driverDeps() driver.Deps {
+	return driver.Deps{
+		Logger:     s.logger.Named("driver"),
+		Registry:   s.networkRegistry,
+		KeyManager: s.keyManager,
+		RPCTimeout: s.settings.rpcTimeout(),
+	}
+}
+
+func (s *Service) driverForNetwork(network string) (driver.Driver, error) {
+	if s.drivers == nil {
+		return nil, merrors.Internal("chain drivers not configured")
+	}
+	return s.drivers.Driver(network)
+}

api/gateway/chain/storage/model/wallet.go

@@ -5,6 +5,7 @@ import (
 	"time"
 
 	"github.com/tech/sendico/pkg/db/storable"
+	pkgmodel "github.com/tech/sendico/pkg/model"
 	"github.com/tech/sendico/pkg/mservice"
 	moneyv1 "github.com/tech/sendico/pkg/proto/common/money/v1"
 )
@@ -19,7 +20,8 @@ const (
 
 // ManagedWallet represents a user-controlled on-chain wallet managed by the service.
 type ManagedWallet struct {
-	storable.Base `bson:",inline" json:",inline"`
+	storable.Base        `bson:",inline" json:",inline"`
+	pkgmodel.Describable `bson:",inline" json:",inline"`
 
 	IdempotencyKey  string              `bson:"idempotencyKey" json:"idempotencyKey"`
 	WalletRef       string              `bson:"walletRef" json:"walletRef"`
@@ -45,6 +47,7 @@ type WalletBalance struct {
 
 	WalletRef       string         `bson:"walletRef" json:"walletRef"`
 	Available       *moneyv1.Money `bson:"available" json:"available"`
+	NativeAvailable *moneyv1.Money `bson:"nativeAvailable,omitempty" json:"nativeAvailable,omitempty"`
 	PendingInbound  *moneyv1.Money `bson:"pendingInbound,omitempty" json:"pendingInbound,omitempty"`
 	PendingOutbound *moneyv1.Money `bson:"pendingOutbound,omitempty" json:"pendingOutbound,omitempty"`
 	CalculatedAt    time.Time      `bson:"calculatedAt" json:"calculatedAt"`
@@ -77,10 +80,19 @@ func (m *ManagedWallet) Normalize() {
 	m.WalletRef = strings.TrimSpace(m.WalletRef)
 	m.OrganizationRef = strings.TrimSpace(m.OrganizationRef)
 	m.OwnerRef = strings.TrimSpace(m.OwnerRef)
+	m.Name = strings.TrimSpace(m.Name)
+	if m.Description != nil {
+		desc := strings.TrimSpace(*m.Description)
+		if desc == "" {
+			m.Description = nil
+		} else {
+			m.Description = &desc
+		}
+	}
 	m.Network = strings.TrimSpace(strings.ToLower(m.Network))
 	m.TokenSymbol = strings.TrimSpace(strings.ToUpper(m.TokenSymbol))
 	m.ContractAddress = strings.TrimSpace(strings.ToLower(m.ContractAddress))
-	m.DepositAddress = strings.TrimSpace(strings.ToLower(m.DepositAddress))
+	m.DepositAddress = normalizeWalletAddress(m.DepositAddress)
 	m.KeyReference = strings.TrimSpace(m.KeyReference)
 }
 
@@ -88,3 +100,31 @@ func (m *ManagedWallet) Normalize() {
 func (b *WalletBalance) Normalize() {
 	b.WalletRef = strings.TrimSpace(b.WalletRef)
 }
+
+func normalizeWalletAddress(address string) string {
+	trimmed := strings.TrimSpace(address)
+	if trimmed == "" {
+		return ""
+	}
+	if isHexAddress(trimmed) {
+		return strings.ToLower(trimmed)
+	}
+	return trimmed
+}
+
+func isHexAddress(value string) bool {
+	trimmed := strings.TrimPrefix(strings.TrimSpace(value), "0x")
+	if len(trimmed) != 40 && len(trimmed) != 42 {
+		return false
+	}
+	for _, r := range trimmed {
+		switch {
+		case r >= '0' && r <= '9':
+		case r >= 'a' && r <= 'f':
+		case r >= 'A' && r <= 'F':
+		default:
+			return false
+		}
+	}
+	return true
+}

api/gateway/mntx/go.mod

@@ -11,8 +11,8 @@ require (
 	github.com/shopspring/decimal v1.4.0
 	github.com/tech/sendico/pkg v0.1.0
 	go.uber.org/zap v1.27.1
-	google.golang.org/grpc v1.77.0
-	google.golang.org/protobuf v1.36.10
+	google.golang.org/grpc v1.78.0
+	google.golang.org/protobuf v1.36.11
 	gopkg.in/yaml.v3 v3.0.1
 )
 
@@ -30,7 +30,7 @@ require (
 	github.com/mitchellh/mapstructure v1.5.0 // indirect
 	github.com/montanaflynn/stats v0.7.1 // indirect
 	github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 // indirect
-	github.com/nats-io/nats.go v1.47.0 // indirect
+	github.com/nats-io/nats.go v1.48.0 // indirect
 	github.com/nats-io/nkeys v0.4.12 // indirect
 	github.com/nats-io/nuid v1.0.1 // indirect
 	github.com/prometheus/client_model v0.6.2 // indirect
@@ -50,5 +50,5 @@ require (
 	golang.org/x/sync v0.19.0 // indirect
 	golang.org/x/sys v0.39.0 // indirect
 	golang.org/x/text v0.32.0 // indirect
-	google.golang.org/genproto/googleapis/rpc v0.0.0-20251202230838-ff82c1b0f217 // indirect
+	google.golang.org/genproto/googleapis/rpc v0.0.0-20251222181119-0a764e51fe1b // indirect
 )

api/gateway/mntx/go.sum

@@ -95,8 +95,8 @@ github.com/morikuni/aec v1.0.0 h1:nP9CBfwrvYnBRgY6qfDQkygYDmYwOilePFkwzv4dU8A=
 github.com/morikuni/aec v1.0.0/go.mod h1:BbKIizmSmc5MMPqRYbxO4ZU0S0+P200+tUnFx7PXmsc=
 github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 h1:C3w9PqII01/Oq1c1nUAm88MOHcQC9l5mIlSMApZMrHA=
 github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822/go.mod h1:+n7T8mK8HuQTcFwEeznm/DIxMOiR9yIdICNftLE1DvQ=
-github.com/nats-io/nats.go v1.47.0 h1:YQdADw6J/UfGUd2Oy6tn4Hq6YHxCaJrVKayxxFqYrgM=
-github.com/nats-io/nats.go v1.47.0/go.mod h1:iRWIPokVIFbVijxuMQq4y9ttaBTMe0SFdlZfMDd+33g=
+github.com/nats-io/nats.go v1.48.0 h1:pSFyXApG+yWU/TgbKCjmm5K4wrHu86231/w84qRVR+U=
+github.com/nats-io/nats.go v1.48.0/go.mod h1:iRWIPokVIFbVijxuMQq4y9ttaBTMe0SFdlZfMDd+33g=
 github.com/nats-io/nkeys v0.4.12 h1:nssm7JKOG9/x4J8II47VWCL1Ds29avyiQDRn0ckMvDc=
 github.com/nats-io/nkeys v0.4.12/go.mod h1:MT59A1HYcjIcyQDJStTfaOY6vhy9XTUjOFo+SVsvpBg=
 github.com/nats-io/nuid v1.0.1 h1:5iA8DT8V7q8WK2EScv2padNa/rTESc1KdnPw4TC2paw=
@@ -214,12 +214,12 @@ golang.org/x/tools v0.1.12/go.mod h1:hNGJHUnrk76NpqgfD5Aqm5Crs+Hm0VOH/i9J2+nxYbc
 golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 gonum.org/v1/gonum v0.16.0 h1:5+ul4Swaf3ESvrOnidPp4GZbzf0mxVQpDCYUQE7OJfk=
 gonum.org/v1/gonum v0.16.0/go.mod h1:fef3am4MQ93R2HHpKnLk4/Tbh/s0+wqD5nfa6Pnwy4E=
-google.golang.org/genproto/googleapis/rpc v0.0.0-20251202230838-ff82c1b0f217 h1:gRkg/vSppuSQoDjxyiGfN4Upv/h/DQmIR10ZU8dh4Ww=
-google.golang.org/genproto/googleapis/rpc v0.0.0-20251202230838-ff82c1b0f217/go.mod h1:7i2o+ce6H/6BluujYR+kqX3GKH+dChPTQU19wjRPiGk=
-google.golang.org/grpc v1.77.0 h1:wVVY6/8cGA6vvffn+wWK5ToddbgdU3d8MNENr4evgXM=
-google.golang.org/grpc v1.77.0/go.mod h1:z0BY1iVj0q8E1uSQCjL9cppRj+gnZjzDnzV0dHhrNig=
-google.golang.org/protobuf v1.36.10 h1:AYd7cD/uASjIL6Q9LiTjz8JLcrh/88q5UObnmY3aOOE=
-google.golang.org/protobuf v1.36.10/go.mod h1:HTf+CrKn2C3g5S8VImy6tdcUvCska2kB7j23XfzDpco=
+google.golang.org/genproto/googleapis/rpc v0.0.0-20251222181119-0a764e51fe1b h1:Mv8VFug0MP9e5vUxfBcE3vUkV6CImK3cMNMIDFjmzxU=
+google.golang.org/genproto/googleapis/rpc v0.0.0-20251222181119-0a764e51fe1b/go.mod h1:j9x/tPzZkyxcgEFkiKEEGxfvyumM01BEtsW8xzOahRQ=
+google.golang.org/grpc v1.78.0 h1:K1XZG/yGDJnzMdd/uZHAkVqJE+xIDOcmdSFZkBUicNc=
+google.golang.org/grpc v1.78.0/go.mod h1:I47qjTo4OKbMkjA/aOOwxDIiPSBofUtQUI5EfpWvW7U=
+google.golang.org/protobuf v1.36.11 h1:fV6ZwhNocDyBLK0dj+fg8ektcVegBBuEolpbTQyBNVE=
+google.golang.org/protobuf v1.36.11/go.mod h1:HTf+CrKn2C3g5S8VImy6tdcUvCska2kB7j23XfzDpco=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c h1:Hei/4ADfdWqJk1ZMxUNpqntNwaWcugrBjAiHlqqRiVk=
 gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c/go.mod h1:JHkPIbrfpd72SG/EVd6muEfDQjcINNoR0C8j2r3qZ4Q=

api/ledger/go.mod

@@ -11,8 +11,8 @@ require (
 	github.com/tech/sendico/pkg v0.1.0
 	go.mongodb.org/mongo-driver v1.17.6
 	go.uber.org/zap v1.27.1
-	google.golang.org/grpc v1.77.0
-	google.golang.org/protobuf v1.36.10
+	google.golang.org/grpc v1.78.0
+	google.golang.org/protobuf v1.36.11
 	gopkg.in/yaml.v3 v3.0.1
 )
 
@@ -33,7 +33,7 @@ require (
 	github.com/mitchellh/mapstructure v1.5.0 // indirect
 	github.com/montanaflynn/stats v0.7.1 // indirect
 	github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 // indirect
-	github.com/nats-io/nats.go v1.47.0 // indirect
+	github.com/nats-io/nats.go v1.48.0 // indirect
 	github.com/nats-io/nkeys v0.4.12 // indirect
 	github.com/nats-io/nuid v1.0.1 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
@@ -51,5 +51,5 @@ require (
 	golang.org/x/sync v0.19.0 // indirect
 	golang.org/x/sys v0.39.0 // indirect
 	golang.org/x/text v0.32.0 // indirect
-	google.golang.org/genproto/googleapis/rpc v0.0.0-20251202230838-ff82c1b0f217 // indirect
+	google.golang.org/genproto/googleapis/rpc v0.0.0-20251222181119-0a764e51fe1b // indirect
 )

api/ledger/go.sum

@@ -95,8 +95,8 @@ github.com/morikuni/aec v1.0.0 h1:nP9CBfwrvYnBRgY6qfDQkygYDmYwOilePFkwzv4dU8A=
 github.com/morikuni/aec v1.0.0/go.mod h1:BbKIizmSmc5MMPqRYbxO4ZU0S0+P200+tUnFx7PXmsc=
 github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 h1:C3w9PqII01/Oq1c1nUAm88MOHcQC9l5mIlSMApZMrHA=
 github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822/go.mod h1:+n7T8mK8HuQTcFwEeznm/DIxMOiR9yIdICNftLE1DvQ=
-github.com/nats-io/nats.go v1.47.0 h1:YQdADw6J/UfGUd2Oy6tn4Hq6YHxCaJrVKayxxFqYrgM=
-github.com/nats-io/nats.go v1.47.0/go.mod h1:iRWIPokVIFbVijxuMQq4y9ttaBTMe0SFdlZfMDd+33g=
+github.com/nats-io/nats.go v1.48.0 h1:pSFyXApG+yWU/TgbKCjmm5K4wrHu86231/w84qRVR+U=
+github.com/nats-io/nats.go v1.48.0/go.mod h1:iRWIPokVIFbVijxuMQq4y9ttaBTMe0SFdlZfMDd+33g=
 github.com/nats-io/nkeys v0.4.12 h1:nssm7JKOG9/x4J8II47VWCL1Ds29avyiQDRn0ckMvDc=
 github.com/nats-io/nkeys v0.4.12/go.mod h1:MT59A1HYcjIcyQDJStTfaOY6vhy9XTUjOFo+SVsvpBg=
 github.com/nats-io/nuid v1.0.1 h1:5iA8DT8V7q8WK2EScv2padNa/rTESc1KdnPw4TC2paw=
@@ -214,12 +214,12 @@ golang.org/x/tools v0.1.12/go.mod h1:hNGJHUnrk76NpqgfD5Aqm5Crs+Hm0VOH/i9J2+nxYbc
 golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 gonum.org/v1/gonum v0.16.0 h1:5+ul4Swaf3ESvrOnidPp4GZbzf0mxVQpDCYUQE7OJfk=
 gonum.org/v1/gonum v0.16.0/go.mod h1:fef3am4MQ93R2HHpKnLk4/Tbh/s0+wqD5nfa6Pnwy4E=
-google.golang.org/genproto/googleapis/rpc v0.0.0-20251202230838-ff82c1b0f217 h1:gRkg/vSppuSQoDjxyiGfN4Upv/h/DQmIR10ZU8dh4Ww=
-google.golang.org/genproto/googleapis/rpc v0.0.0-20251202230838-ff82c1b0f217/go.mod h1:7i2o+ce6H/6BluujYR+kqX3GKH+dChPTQU19wjRPiGk=
-google.golang.org/grpc v1.77.0 h1:wVVY6/8cGA6vvffn+wWK5ToddbgdU3d8MNENr4evgXM=
-google.golang.org/grpc v1.77.0/go.mod h1:z0BY1iVj0q8E1uSQCjL9cppRj+gnZjzDnzV0dHhrNig=
-google.golang.org/protobuf v1.36.10 h1:AYd7cD/uASjIL6Q9LiTjz8JLcrh/88q5UObnmY3aOOE=
-google.golang.org/protobuf v1.36.10/go.mod h1:HTf+CrKn2C3g5S8VImy6tdcUvCska2kB7j23XfzDpco=
+google.golang.org/genproto/googleapis/rpc v0.0.0-20251222181119-0a764e51fe1b h1:Mv8VFug0MP9e5vUxfBcE3vUkV6CImK3cMNMIDFjmzxU=
+google.golang.org/genproto/googleapis/rpc v0.0.0-20251222181119-0a764e51fe1b/go.mod h1:j9x/tPzZkyxcgEFkiKEEGxfvyumM01BEtsW8xzOahRQ=
+google.golang.org/grpc v1.78.0 h1:K1XZG/yGDJnzMdd/uZHAkVqJE+xIDOcmdSFZkBUicNc=
+google.golang.org/grpc v1.78.0/go.mod h1:I47qjTo4OKbMkjA/aOOwxDIiPSBofUtQUI5EfpWvW7U=
+google.golang.org/protobuf v1.36.11 h1:fV6ZwhNocDyBLK0dj+fg8ektcVegBBuEolpbTQyBNVE=
+google.golang.org/protobuf v1.36.11/go.mod h1:HTf+CrKn2C3g5S8VImy6tdcUvCska2kB7j23XfzDpco=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c h1:Hei/4ADfdWqJk1ZMxUNpqntNwaWcugrBjAiHlqqRiVk=
 gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c/go.mod h1:JHkPIbrfpd72SG/EVd6muEfDQjcINNoR0C8j2r3qZ4Q=

api/notification/go.mod

@@ -33,7 +33,7 @@ require (
 	github.com/mattn/go-isatty v0.0.20 // indirect
 	github.com/montanaflynn/stats v0.7.1 // indirect
 	github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 // indirect
-	github.com/nats-io/nats.go v1.47.0 // indirect
+	github.com/nats-io/nats.go v1.48.0 // indirect
 	github.com/nats-io/nkeys v0.4.12 // indirect
 	github.com/nats-io/nuid v1.0.1 // indirect
 	github.com/prometheus/client_golang v1.23.2 // indirect
@@ -52,7 +52,7 @@ require (
 	golang.org/x/net v0.48.0 // indirect
 	golang.org/x/sync v0.19.0 // indirect
 	golang.org/x/sys v0.39.0 // indirect
-	google.golang.org/genproto/googleapis/rpc v0.0.0-20251202230838-ff82c1b0f217 // indirect
-	google.golang.org/grpc v1.77.0 // indirect
-	google.golang.org/protobuf v1.36.10 // indirect
+	google.golang.org/genproto/googleapis/rpc v0.0.0-20251222181119-0a764e51fe1b // indirect
+	google.golang.org/grpc v1.78.0 // indirect
+	google.golang.org/protobuf v1.36.11 // indirect
 )

api/notification/go.sum

@@ -99,8 +99,8 @@ github.com/morikuni/aec v1.0.0 h1:nP9CBfwrvYnBRgY6qfDQkygYDmYwOilePFkwzv4dU8A=
 github.com/morikuni/aec v1.0.0/go.mod h1:BbKIizmSmc5MMPqRYbxO4ZU0S0+P200+tUnFx7PXmsc=
 github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 h1:C3w9PqII01/Oq1c1nUAm88MOHcQC9l5mIlSMApZMrHA=
 github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822/go.mod h1:+n7T8mK8HuQTcFwEeznm/DIxMOiR9yIdICNftLE1DvQ=
-github.com/nats-io/nats.go v1.47.0 h1:YQdADw6J/UfGUd2Oy6tn4Hq6YHxCaJrVKayxxFqYrgM=
-github.com/nats-io/nats.go v1.47.0/go.mod h1:iRWIPokVIFbVijxuMQq4y9ttaBTMe0SFdlZfMDd+33g=
+github.com/nats-io/nats.go v1.48.0 h1:pSFyXApG+yWU/TgbKCjmm5K4wrHu86231/w84qRVR+U=
+github.com/nats-io/nats.go v1.48.0/go.mod h1:iRWIPokVIFbVijxuMQq4y9ttaBTMe0SFdlZfMDd+33g=
 github.com/nats-io/nkeys v0.4.12 h1:nssm7JKOG9/x4J8II47VWCL1Ds29avyiQDRn0ckMvDc=
 github.com/nats-io/nkeys v0.4.12/go.mod h1:MT59A1HYcjIcyQDJStTfaOY6vhy9XTUjOFo+SVsvpBg=
 github.com/nats-io/nuid v1.0.1 h1:5iA8DT8V7q8WK2EScv2padNa/rTESc1KdnPw4TC2paw=
@@ -227,12 +227,12 @@ golang.org/x/tools v0.1.12/go.mod h1:hNGJHUnrk76NpqgfD5Aqm5Crs+Hm0VOH/i9J2+nxYbc
 golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 gonum.org/v1/gonum v0.16.0 h1:5+ul4Swaf3ESvrOnidPp4GZbzf0mxVQpDCYUQE7OJfk=
 gonum.org/v1/gonum v0.16.0/go.mod h1:fef3am4MQ93R2HHpKnLk4/Tbh/s0+wqD5nfa6Pnwy4E=
-google.golang.org/genproto/googleapis/rpc v0.0.0-20251202230838-ff82c1b0f217 h1:gRkg/vSppuSQoDjxyiGfN4Upv/h/DQmIR10ZU8dh4Ww=
-google.golang.org/genproto/googleapis/rpc v0.0.0-20251202230838-ff82c1b0f217/go.mod h1:7i2o+ce6H/6BluujYR+kqX3GKH+dChPTQU19wjRPiGk=
-google.golang.org/grpc v1.77.0 h1:wVVY6/8cGA6vvffn+wWK5ToddbgdU3d8MNENr4evgXM=
-google.golang.org/grpc v1.77.0/go.mod h1:z0BY1iVj0q8E1uSQCjL9cppRj+gnZjzDnzV0dHhrNig=
-google.golang.org/protobuf v1.36.10 h1:AYd7cD/uASjIL6Q9LiTjz8JLcrh/88q5UObnmY3aOOE=
-google.golang.org/protobuf v1.36.10/go.mod h1:HTf+CrKn2C3g5S8VImy6tdcUvCska2kB7j23XfzDpco=
+google.golang.org/genproto/googleapis/rpc v0.0.0-20251222181119-0a764e51fe1b h1:Mv8VFug0MP9e5vUxfBcE3vUkV6CImK3cMNMIDFjmzxU=
+google.golang.org/genproto/googleapis/rpc v0.0.0-20251222181119-0a764e51fe1b/go.mod h1:j9x/tPzZkyxcgEFkiKEEGxfvyumM01BEtsW8xzOahRQ=
+google.golang.org/grpc v1.78.0 h1:K1XZG/yGDJnzMdd/uZHAkVqJE+xIDOcmdSFZkBUicNc=
+google.golang.org/grpc v1.78.0/go.mod h1:I47qjTo4OKbMkjA/aOOwxDIiPSBofUtQUI5EfpWvW7U=
+google.golang.org/protobuf v1.36.11 h1:fV6ZwhNocDyBLK0dj+fg8ektcVegBBuEolpbTQyBNVE=
+google.golang.org/protobuf v1.36.11/go.mod h1:HTf+CrKn2C3g5S8VImy6tdcUvCska2kB7j23XfzDpco=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c h1:Hei/4ADfdWqJk1ZMxUNpqntNwaWcugrBjAiHlqqRiVk=
 gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c/go.mod h1:JHkPIbrfpd72SG/EVd6muEfDQjcINNoR0C8j2r3qZ4Q=

api/payments/orchestrator/client/client.go

@@ -17,6 +17,8 @@ import (
 // Client exposes typed helpers around the payment orchestrator gRPC API.
 type Client interface {
 	QuotePayment(ctx context.Context, req *orchestratorv1.QuotePaymentRequest) (*orchestratorv1.QuotePaymentResponse, error)
+	QuotePayments(ctx context.Context, req *orchestratorv1.QuotePaymentsRequest) (*orchestratorv1.QuotePaymentsResponse, error)
+	InitiatePayments(ctx context.Context, req *orchestratorv1.InitiatePaymentsRequest) (*orchestratorv1.InitiatePaymentsResponse, error)
 	InitiatePayment(ctx context.Context, req *orchestratorv1.InitiatePaymentRequest) (*orchestratorv1.InitiatePaymentResponse, error)
 	CancelPayment(ctx context.Context, req *orchestratorv1.CancelPaymentRequest) (*orchestratorv1.CancelPaymentResponse, error)
 	GetPayment(ctx context.Context, req *orchestratorv1.GetPaymentRequest) (*orchestratorv1.GetPaymentResponse, error)
@@ -29,6 +31,8 @@ type Client interface {
 
 type grpcOrchestratorClient interface {
 	QuotePayment(ctx context.Context, in *orchestratorv1.QuotePaymentRequest, opts ...grpc.CallOption) (*orchestratorv1.QuotePaymentResponse, error)
+	QuotePayments(ctx context.Context, in *orchestratorv1.QuotePaymentsRequest, opts ...grpc.CallOption) (*orchestratorv1.QuotePaymentsResponse, error)
+	InitiatePayments(ctx context.Context, in *orchestratorv1.InitiatePaymentsRequest, opts ...grpc.CallOption) (*orchestratorv1.InitiatePaymentsResponse, error)
 	InitiatePayment(ctx context.Context, in *orchestratorv1.InitiatePaymentRequest, opts ...grpc.CallOption) (*orchestratorv1.InitiatePaymentResponse, error)
 	CancelPayment(ctx context.Context, in *orchestratorv1.CancelPaymentRequest, opts ...grpc.CallOption) (*orchestratorv1.CancelPaymentResponse, error)
 	GetPayment(ctx context.Context, in *orchestratorv1.GetPaymentRequest, opts ...grpc.CallOption) (*orchestratorv1.GetPaymentResponse, error)
@@ -97,6 +101,18 @@ func (c *orchestratorClient) QuotePayment(ctx context.Context, req *orchestrator
 	return c.client.QuotePayment(ctx, req)
 }
 
+func (c *orchestratorClient) QuotePayments(ctx context.Context, req *orchestratorv1.QuotePaymentsRequest) (*orchestratorv1.QuotePaymentsResponse, error) {
+	ctx, cancel := c.callContext(ctx)
+	defer cancel()
+	return c.client.QuotePayments(ctx, req)
+}
+
+func (c *orchestratorClient) InitiatePayments(ctx context.Context, req *orchestratorv1.InitiatePaymentsRequest) (*orchestratorv1.InitiatePaymentsResponse, error) {
+	ctx, cancel := c.callContext(ctx)
+	defer cancel()
+	return c.client.InitiatePayments(ctx, req)
+}
+
 func (c *orchestratorClient) InitiatePayment(ctx context.Context, req *orchestratorv1.InitiatePaymentRequest) (*orchestratorv1.InitiatePaymentResponse, error) {
 	ctx, cancel := c.callContext(ctx)
 	defer cancel()

api/payments/orchestrator/client/fake.go

@@ -9,6 +9,8 @@ import (
 // Fake implements Client for tests.
 type Fake struct {
 	QuotePaymentFn           func(ctx context.Context, req *orchestratorv1.QuotePaymentRequest) (*orchestratorv1.QuotePaymentResponse, error)
+	QuotePaymentsFn          func(ctx context.Context, req *orchestratorv1.QuotePaymentsRequest) (*orchestratorv1.QuotePaymentsResponse, error)
+	InitiatePaymentsFn       func(ctx context.Context, req *orchestratorv1.InitiatePaymentsRequest) (*orchestratorv1.InitiatePaymentsResponse, error)
 	InitiatePaymentFn        func(ctx context.Context, req *orchestratorv1.InitiatePaymentRequest) (*orchestratorv1.InitiatePaymentResponse, error)
 	CancelPaymentFn          func(ctx context.Context, req *orchestratorv1.CancelPaymentRequest) (*orchestratorv1.CancelPaymentResponse, error)
 	GetPaymentFn             func(ctx context.Context, req *orchestratorv1.GetPaymentRequest) (*orchestratorv1.GetPaymentResponse, error)
@@ -26,6 +28,20 @@ func (f *Fake) QuotePayment(ctx context.Context, req *orchestratorv1.QuotePaymen
 	return &orchestratorv1.QuotePaymentResponse{}, nil
 }
 
+func (f *Fake) QuotePayments(ctx context.Context, req *orchestratorv1.QuotePaymentsRequest) (*orchestratorv1.QuotePaymentsResponse, error) {
+	if f.QuotePaymentsFn != nil {
+		return f.QuotePaymentsFn(ctx, req)
+	}
+	return &orchestratorv1.QuotePaymentsResponse{}, nil
+}
+
+func (f *Fake) InitiatePayments(ctx context.Context, req *orchestratorv1.InitiatePaymentsRequest) (*orchestratorv1.InitiatePaymentsResponse, error) {
+	if f.InitiatePaymentsFn != nil {
+		return f.InitiatePaymentsFn(ctx, req)
+	}
+	return &orchestratorv1.InitiatePaymentsResponse{}, nil
+}
+
 func (f *Fake) InitiatePayment(ctx context.Context, req *orchestratorv1.InitiatePaymentRequest) (*orchestratorv1.InitiatePaymentResponse, error) {
 	if f.InitiatePaymentFn != nil {
 		return f.InitiatePaymentFn(ctx, req)

api/payments/orchestrator/config.yml

@@ -59,5 +59,8 @@ oracle:
 
 card_gateways:
   monetix:
-    funding_address: "wallet_funding_monetix"
-    fee_address: "wallet_fee_monetix"
+    funding_address: "TXtjmjF99MhMdaMQrLopzcQ8cSBRLq5co8"
+    fee_wallet_ref: "694c124fd76f9f811ac57134"
+
+fee_ledger_accounts:
+  monetix: "ledger:fees:monetix"

api/payments/orchestrator/go.mod

@@ -24,8 +24,8 @@ require (
 	github.com/tech/sendico/pkg v0.1.0
 	go.mongodb.org/mongo-driver v1.17.6
 	go.uber.org/zap v1.27.1
-	google.golang.org/grpc v1.77.0
-	google.golang.org/protobuf v1.36.10
+	google.golang.org/grpc v1.78.0
+	google.golang.org/protobuf v1.36.11
 	gopkg.in/yaml.v3 v3.0.1
 )
 
@@ -45,7 +45,7 @@ require (
 	github.com/mitchellh/mapstructure v1.5.0 // indirect
 	github.com/montanaflynn/stats v0.7.1 // indirect
 	github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 // indirect
-	github.com/nats-io/nats.go v1.47.0 // indirect
+	github.com/nats-io/nats.go v1.48.0 // indirect
 	github.com/nats-io/nkeys v0.4.12 // indirect
 	github.com/nats-io/nuid v1.0.1 // indirect
 	github.com/prometheus/client_model v0.6.2 // indirect
@@ -62,5 +62,5 @@ require (
 	golang.org/x/sync v0.19.0 // indirect
 	golang.org/x/sys v0.39.0 // indirect
 	golang.org/x/text v0.32.0 // indirect
-	google.golang.org/genproto/googleapis/rpc v0.0.0-20251202230838-ff82c1b0f217 // indirect
+	google.golang.org/genproto/googleapis/rpc v0.0.0-20251222181119-0a764e51fe1b // indirect
 )

api/payments/orchestrator/go.sum

@@ -95,8 +95,8 @@ github.com/morikuni/aec v1.0.0 h1:nP9CBfwrvYnBRgY6qfDQkygYDmYwOilePFkwzv4dU8A=
 github.com/morikuni/aec v1.0.0/go.mod h1:BbKIizmSmc5MMPqRYbxO4ZU0S0+P200+tUnFx7PXmsc=
 github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 h1:C3w9PqII01/Oq1c1nUAm88MOHcQC9l5mIlSMApZMrHA=
 github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822/go.mod h1:+n7T8mK8HuQTcFwEeznm/DIxMOiR9yIdICNftLE1DvQ=
-github.com/nats-io/nats.go v1.47.0 h1:YQdADw6J/UfGUd2Oy6tn4Hq6YHxCaJrVKayxxFqYrgM=
-github.com/nats-io/nats.go v1.47.0/go.mod h1:iRWIPokVIFbVijxuMQq4y9ttaBTMe0SFdlZfMDd+33g=
+github.com/nats-io/nats.go v1.48.0 h1:pSFyXApG+yWU/TgbKCjmm5K4wrHu86231/w84qRVR+U=
+github.com/nats-io/nats.go v1.48.0/go.mod h1:iRWIPokVIFbVijxuMQq4y9ttaBTMe0SFdlZfMDd+33g=
 github.com/nats-io/nkeys v0.4.12 h1:nssm7JKOG9/x4J8II47VWCL1Ds29avyiQDRn0ckMvDc=
 github.com/nats-io/nkeys v0.4.12/go.mod h1:MT59A1HYcjIcyQDJStTfaOY6vhy9XTUjOFo+SVsvpBg=
 github.com/nats-io/nuid v1.0.1 h1:5iA8DT8V7q8WK2EScv2padNa/rTESc1KdnPw4TC2paw=
@@ -215,12 +215,12 @@ golang.org/x/tools v0.1.12/go.mod h1:hNGJHUnrk76NpqgfD5Aqm5Crs+Hm0VOH/i9J2+nxYbc
 golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 gonum.org/v1/gonum v0.16.0 h1:5+ul4Swaf3ESvrOnidPp4GZbzf0mxVQpDCYUQE7OJfk=
 gonum.org/v1/gonum v0.16.0/go.mod h1:fef3am4MQ93R2HHpKnLk4/Tbh/s0+wqD5nfa6Pnwy4E=
-google.golang.org/genproto/googleapis/rpc v0.0.0-20251202230838-ff82c1b0f217 h1:gRkg/vSppuSQoDjxyiGfN4Upv/h/DQmIR10ZU8dh4Ww=
-google.golang.org/genproto/googleapis/rpc v0.0.0-20251202230838-ff82c1b0f217/go.mod h1:7i2o+ce6H/6BluujYR+kqX3GKH+dChPTQU19wjRPiGk=
-google.golang.org/grpc v1.77.0 h1:wVVY6/8cGA6vvffn+wWK5ToddbgdU3d8MNENr4evgXM=
-google.golang.org/grpc v1.77.0/go.mod h1:z0BY1iVj0q8E1uSQCjL9cppRj+gnZjzDnzV0dHhrNig=
-google.golang.org/protobuf v1.36.10 h1:AYd7cD/uASjIL6Q9LiTjz8JLcrh/88q5UObnmY3aOOE=
-google.golang.org/protobuf v1.36.10/go.mod h1:HTf+CrKn2C3g5S8VImy6tdcUvCska2kB7j23XfzDpco=
+google.golang.org/genproto/googleapis/rpc v0.0.0-20251222181119-0a764e51fe1b h1:Mv8VFug0MP9e5vUxfBcE3vUkV6CImK3cMNMIDFjmzxU=
+google.golang.org/genproto/googleapis/rpc v0.0.0-20251222181119-0a764e51fe1b/go.mod h1:j9x/tPzZkyxcgEFkiKEEGxfvyumM01BEtsW8xzOahRQ=
+google.golang.org/grpc v1.78.0 h1:K1XZG/yGDJnzMdd/uZHAkVqJE+xIDOcmdSFZkBUicNc=
+google.golang.org/grpc v1.78.0/go.mod h1:I47qjTo4OKbMkjA/aOOwxDIiPSBofUtQUI5EfpWvW7U=
+google.golang.org/protobuf v1.36.11 h1:fV6ZwhNocDyBLK0dj+fg8ektcVegBBuEolpbTQyBNVE=
+google.golang.org/protobuf v1.36.11/go.mod h1:HTf+CrKn2C3g5S8VImy6tdcUvCska2kB7j23XfzDpco=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c h1:Hei/4ADfdWqJk1ZMxUNpqntNwaWcugrBjAiHlqqRiVk=
 gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c/go.mod h1:JHkPIbrfpd72SG/EVd6muEfDQjcINNoR0C8j2r3qZ4Q=

api/payments/orchestrator/internal/server/internal/serverimp.go

@@ -46,6 +46,7 @@ type config struct {
 	Gateway         clientConfig                      `yaml:"gateway"`
 	Oracle          clientConfig                      `yaml:"oracle"`
 	CardGateways    map[string]cardGatewayRouteConfig `yaml:"card_gateways"`
+	FeeAccounts     map[string]string                 `yaml:"fee_ledger_accounts"`
 }
 
 type clientConfig struct {
@@ -58,6 +59,7 @@ type clientConfig struct {
 type cardGatewayRouteConfig struct {
 	FundingAddress string `yaml:"funding_address"`
 	FeeAddress     string `yaml:"fee_address"`
+	FeeWalletRef   string `yaml:"fee_wallet_ref"`
 }
 
 func (c clientConfig) address() string {
@@ -159,6 +161,9 @@ func (i *Imp) Start() error {
 		if routes := buildCardGatewayRoutes(cfg.CardGateways); len(routes) > 0 {
 			opts = append(opts, orchestrator.WithCardGatewayRoutes(routes))
 		}
+		if feeAccounts := buildFeeLedgerAccounts(cfg.FeeAccounts); len(feeAccounts) > 0 {
+			opts = append(opts, orchestrator.WithFeeLedgerAccounts(feeAccounts))
+		}
 		return orchestrator.NewService(logger, repo, opts...), nil
 	}
 
@@ -319,7 +324,24 @@ func buildCardGatewayRoutes(src map[string]cardGatewayRouteConfig) map[string]or
 		result[trimmedKey] = orchestrator.CardGatewayRoute{
 			FundingAddress: strings.TrimSpace(route.FundingAddress),
 			FeeAddress:     strings.TrimSpace(route.FeeAddress),
+			FeeWalletRef:   strings.TrimSpace(route.FeeWalletRef),
 		}
 	}
 	return result
 }
+
+func buildFeeLedgerAccounts(src map[string]string) map[string]string {
+	if len(src) == 0 {
+		return nil
+	}
+	result := make(map[string]string, len(src))
+	for key, account := range src {
+		k := strings.ToLower(strings.TrimSpace(key))
+		v := strings.TrimSpace(account)
+		if k == "" || v == "" {
+			continue
+		}
+		result[k] = v
+	}
+	return result
+}

api/payments/orchestrator/internal/service/orchestrator/card_payout.go

@@ -7,13 +7,21 @@ import (
 	"github.com/shopspring/decimal"
 	"github.com/tech/sendico/payments/orchestrator/storage/model"
 	"github.com/tech/sendico/pkg/merrors"
+	moneyv1 "github.com/tech/sendico/pkg/proto/common/money/v1"
 	chainv1 "github.com/tech/sendico/pkg/proto/gateway/chain/v1"
 	mntxv1 "github.com/tech/sendico/pkg/proto/gateway/mntx/v1"
 	orchestratorv1 "github.com/tech/sendico/pkg/proto/payments/orchestrator/v1"
 	"go.uber.org/zap"
 )
 
-const defaultCardGateway = "monetix"
+const (
+	defaultCardGateway = "monetix"
+
+	stepCodeGasTopUp        = "gas_top_up"
+	stepCodeFundingTransfer = "funding_transfer"
+	stepCodeCardPayout      = "card_payout"
+	stepCodeFeeTransfer     = "fee_transfer"
+)
 
 func (s *Service) cardRoute(gateway string) (CardGatewayRoute, error) {
 	if len(s.deps.cardRoutes) == 0 {
@@ -54,24 +62,214 @@ func (s *Service) submitCardFundingTransfers(ctx context.Context, payment *model
 	if err != nil {
 		return err
 	}
+	sourceWalletRef := strings.TrimSpace(source.ManagedWalletRef)
+	fundingAddress := strings.TrimSpace(route.FundingAddress)
+	feeWalletRef := strings.TrimSpace(route.FeeWalletRef)
 
 	amount := cloneMoney(intent.Amount)
-	if amount == nil {
+	if amount == nil || strings.TrimSpace(amount.GetAmount()) == "" || strings.TrimSpace(amount.GetCurrency()) == "" {
 		return merrors.InvalidArgument("card funding: amount is required")
 	}
 
+	payoutAmount, err := cardPayoutAmount(payment)
+	if err != nil {
+		return err
+	}
+
+	feeMoney := (*moneyv1.Money)(nil)
+	if quote != nil {
+		feeMoney = quote.GetExpectedFeeTotal()
+	}
+	if feeMoney == nil && payment.LastQuote != nil {
+		feeMoney = payment.LastQuote.ExpectedFeeTotal
+	}
+	feeDecimal := decimal.Zero
+	if feeMoney != nil && strings.TrimSpace(feeMoney.GetAmount()) != "" {
+		if strings.TrimSpace(feeMoney.GetCurrency()) == "" {
+			return merrors.InvalidArgument("card funding: fee currency is required")
+		}
+		feeDecimal, err = decimalFromMoney(feeMoney)
+		if err != nil {
+			return err
+		}
+	}
+	feeRequired := feeDecimal.IsPositive()
+
+	fundingDest := &chainv1.TransferDestination{
+		Destination: &chainv1.TransferDestination_ExternalAddress{ExternalAddress: fundingAddress},
+	}
+	fundingFee, err := s.estimateTransferNetworkFee(ctx, sourceWalletRef, fundingDest, amount)
+	if err != nil {
+		return err
+	}
+
+	var feeTransferFee *moneyv1.Money
+	if feeRequired {
+		if feeWalletRef == "" {
+			return merrors.InvalidArgument("card funding: fee wallet ref is required when fee exists")
+		}
+		feeDest := &chainv1.TransferDestination{
+			Destination: &chainv1.TransferDestination_ManagedWalletRef{ManagedWalletRef: feeWalletRef},
+		}
+		feeTransferFee, err = s.estimateTransferNetworkFee(ctx, sourceWalletRef, feeDest, feeMoney)
+		if err != nil {
+			return err
+		}
+	}
+
+	totalFee, gasCurrency, err := sumNetworkFees(fundingFee, feeTransferFee)
+	if err != nil {
+		return err
+	}
+
+	var estimatedTotalFee *moneyv1.Money
+	if gasCurrency != "" && !totalFee.IsNegative() {
+		estimatedTotalFee = makeMoney(gasCurrency, totalFee)
+	}
+
+	var topUpMoney *moneyv1.Money
+	var topUpFee *moneyv1.Money
+	topUpPositive := false
+	if estimatedTotalFee != nil {
+		computeResp, err := s.deps.gateway.client.ComputeGasTopUp(ctx, &chainv1.ComputeGasTopUpRequest{
+			WalletRef:         sourceWalletRef,
+			EstimatedTotalFee: estimatedTotalFee,
+		})
+		if err != nil {
+			s.logger.Warn("card funding gas top-up compute failed", zap.Error(err), zap.String("payment_ref", payment.PaymentRef))
+			return err
+		}
+		if computeResp != nil {
+			topUpMoney = computeResp.GetTopupAmount()
+		}
+		if topUpMoney != nil && strings.TrimSpace(topUpMoney.GetAmount()) != "" {
+			amountDec, err := decimalFromMoney(topUpMoney)
+			if err != nil {
+				return err
+			}
+			topUpPositive = amountDec.IsPositive()
+		}
+		if topUpMoney != nil && topUpPositive {
+			if strings.TrimSpace(topUpMoney.GetCurrency()) == "" {
+				return merrors.InvalidArgument("card funding: gas top-up currency is required")
+			}
+			if feeWalletRef == "" {
+				return merrors.InvalidArgument("card funding: fee wallet ref is required for gas top-up")
+			}
+			topUpDest := &chainv1.TransferDestination{
+				Destination: &chainv1.TransferDestination_ManagedWalletRef{ManagedWalletRef: sourceWalletRef},
+			}
+			topUpFee, err = s.estimateTransferNetworkFee(ctx, feeWalletRef, topUpDest, topUpMoney)
+			if err != nil {
+				return err
+			}
+		}
+	}
+
+	plan := ensureExecutionPlan(payment)
+	var gasStep *model.ExecutionStep
+	if topUpMoney != nil && topUpPositive {
+		gasStep = ensureExecutionStep(plan, stepCodeGasTopUp)
+		gasStep.Description = "Top up native gas from fee wallet"
+		gasStep.Amount = cloneMoney(topUpMoney)
+		gasStep.NetworkFee = cloneMoney(topUpFee)
+		gasStep.SourceWalletRef = feeWalletRef
+		gasStep.DestinationRef = sourceWalletRef
+	}
+
+	fundStep := ensureExecutionStep(plan, stepCodeFundingTransfer)
+	fundStep.Description = "Transfer payout amount to card funding wallet"
+	fundStep.Amount = cloneMoney(amount)
+	fundStep.NetworkFee = cloneMoney(fundingFee)
+	fundStep.SourceWalletRef = sourceWalletRef
+	fundStep.DestinationRef = fundingAddress
+
+	cardStep := ensureExecutionStep(plan, stepCodeCardPayout)
+	cardStep.Description = "Submit card payout"
+	cardStep.Amount = cloneMoney(payoutAmount)
+	if card := intent.Destination.Card; card != nil {
+		if masked := strings.TrimSpace(card.MaskedPan); masked != "" {
+			cardStep.DestinationRef = masked
+		}
+	}
+
+	if feeRequired {
+		step := ensureExecutionStep(plan, stepCodeFeeTransfer)
+		step.Description = "Transfer fee to fee wallet"
+		step.Amount = cloneMoney(feeMoney)
+		step.NetworkFee = cloneMoney(feeTransferFee)
+		step.SourceWalletRef = sourceWalletRef
+		step.DestinationRef = feeWalletRef
+	}
+
+	updateExecutionPlanTotalNetworkFee(plan)
+
 	exec := payment.Execution
 	if exec == nil {
 		exec = &model.ExecutionRefs{}
 	}
 
+	if topUpMoney != nil && topUpPositive {
+		ensureResp, gasErr := s.deps.gateway.client.EnsureGasTopUp(ctx, &chainv1.EnsureGasTopUpRequest{
+			IdempotencyKey:    payment.IdempotencyKey + ":card:gas",
+			OrganizationRef:   payment.OrganizationRef.Hex(),
+			SourceWalletRef:   feeWalletRef,
+			TargetWalletRef:   sourceWalletRef,
+			EstimatedTotalFee: estimatedTotalFee,
+			Metadata:          cloneMetadata(payment.Metadata),
+			ClientReference:   payment.PaymentRef,
+		})
+		if gasErr != nil {
+			s.logger.Warn("card gas top-up transfer failed", zap.Error(gasErr), zap.String("payment_ref", payment.PaymentRef))
+			return gasErr
+		}
+		if gasStep != nil {
+			actual := (*moneyv1.Money)(nil)
+			if ensureResp != nil {
+				actual = ensureResp.GetTopupAmount()
+				if transfer := ensureResp.GetTransfer(); transfer != nil {
+					gasStep.TransferRef = strings.TrimSpace(transfer.GetTransferRef())
+				}
+			}
+			actualPositive := false
+			if actual != nil && strings.TrimSpace(actual.GetAmount()) != "" {
+				actualDec, err := decimalFromMoney(actual)
+				if err != nil {
+					return err
+				}
+				actualPositive = actualDec.IsPositive()
+			}
+			if actual != nil && actualPositive {
+				gasStep.Amount = cloneMoney(actual)
+				if strings.TrimSpace(actual.GetCurrency()) == "" {
+					return merrors.InvalidArgument("card funding: gas top-up currency is required")
+				}
+				topUpDest := &chainv1.TransferDestination{
+					Destination: &chainv1.TransferDestination_ManagedWalletRef{ManagedWalletRef: sourceWalletRef},
+				}
+				topUpFee, err = s.estimateTransferNetworkFee(ctx, feeWalletRef, topUpDest, actual)
+				if err != nil {
+					return err
+				}
+				gasStep.NetworkFee = cloneMoney(topUpFee)
+			} else {
+				gasStep.Amount = nil
+				gasStep.NetworkFee = nil
+			}
+		}
+		if gasStep != nil {
+			s.logger.Info("card gas top-up transfer submitted", zap.String("payment_ref", payment.PaymentRef), zap.String("transfer_ref", gasStep.TransferRef))
+		}
+		updateExecutionPlanTotalNetworkFee(plan)
+	}
+
 	// Transfer payout amount to funding wallet.
 	fundReq := &chainv1.SubmitTransferRequest{
 		IdempotencyKey:  payment.IdempotencyKey + ":card:fund",
 		OrganizationRef: payment.OrganizationRef.Hex(),
-		SourceWalletRef: strings.TrimSpace(source.ManagedWalletRef),
+		SourceWalletRef: sourceWalletRef,
 		Destination: &chainv1.TransferDestination{
-			Destination: &chainv1.TransferDestination_ExternalAddress{ExternalAddress: strings.TrimSpace(route.FundingAddress)},
+			Destination: &chainv1.TransferDestination_ExternalAddress{ExternalAddress: fundingAddress},
 		},
 		Amount:          amount,
 		Metadata:        cloneMetadata(payment.Metadata),
@@ -84,42 +282,10 @@ func (s *Service) submitCardFundingTransfers(ctx context.Context, payment *model
 	}
 	if fundResp != nil && fundResp.GetTransfer() != nil {
 		exec.ChainTransferRef = strings.TrimSpace(fundResp.GetTransfer().GetTransferRef())
+		fundStep.TransferRef = exec.ChainTransferRef
 	}
 	s.logger.Info("card funding transfer submitted", zap.String("payment_ref", payment.PaymentRef), zap.String("transfer_ref", exec.ChainTransferRef))
 
-	feeMoney := quote.GetExpectedFeeTotal()
-	if feeMoney != nil && strings.TrimSpace(feeMoney.GetAmount()) != "" {
-		if strings.TrimSpace(route.FeeAddress) == "" {
-			return merrors.InvalidArgument("card funding: fee address is required when fee exists")
-		}
-		feeDecimal, err := decimalFromMoney(feeMoney)
-		if err != nil {
-			return err
-		}
-		if feeDecimal.IsPositive() {
-			feeReq := &chainv1.SubmitTransferRequest{
-				IdempotencyKey:  payment.IdempotencyKey + ":card:fee",
-				OrganizationRef: payment.OrganizationRef.Hex(),
-				SourceWalletRef: strings.TrimSpace(source.ManagedWalletRef),
-				Destination: &chainv1.TransferDestination{
-					Destination: &chainv1.TransferDestination_ExternalAddress{ExternalAddress: strings.TrimSpace(route.FeeAddress)},
-				},
-				Amount:          feeMoney,
-				Metadata:        cloneMetadata(payment.Metadata),
-				ClientReference: payment.PaymentRef,
-			}
-			feeResp, feeErr := s.deps.gateway.client.SubmitTransfer(ctx, feeReq)
-			if feeErr != nil {
-				s.logger.Warn("card fee transfer failed", zap.Error(feeErr), zap.String("payment_ref", payment.PaymentRef))
-				return feeErr
-			}
-			if feeResp != nil && feeResp.GetTransfer() != nil {
-				exec.FeeTransferRef = strings.TrimSpace(feeResp.GetTransfer().GetTransferRef())
-			}
-			s.logger.Info("card fee transfer submitted", zap.String("payment_ref", payment.PaymentRef), zap.String("transfer_ref", exec.FeeTransferRef))
-		}
-	}
-
 	payment.Execution = exec
 	return nil
 }
@@ -133,9 +299,9 @@ func (s *Service) submitCardPayout(ctx context.Context, payment *model.Payment)
 	if card == nil {
 		return merrors.InvalidArgument("card payout: card endpoint is required")
 	}
-	amount := cloneMoney(intent.Amount)
-	if amount == nil || strings.TrimSpace(amount.GetAmount()) == "" || strings.TrimSpace(amount.GetCurrency()) == "" {
-		return merrors.InvalidArgument("card payout: amount is required")
+	amount, err := cardPayoutAmount(payment)
+	if err != nil {
+		return err
 	}
 	amtDec, err := decimalFromMoney(amount)
 	if err != nil {
@@ -193,13 +359,92 @@ func (s *Service) submitCardPayout(ctx context.Context, payment *model.Payment)
 		return merrors.Internal("card payout: missing payout state")
 	}
 	recordCardPayoutState(payment, state)
-	if payment.Execution == nil {
-		payment.Execution = &model.ExecutionRefs{}
+	exec := payment.Execution
+	if exec == nil {
+		exec = &model.ExecutionRefs{}
 	}
-	if payment.Execution.CardPayoutRef == "" {
-		payment.Execution.CardPayoutRef = strings.TrimSpace(state.GetPayoutId())
+	if exec.CardPayoutRef == "" {
+		exec.CardPayoutRef = strings.TrimSpace(state.GetPayoutId())
 	}
-	s.logger.Info("card payout submitted", zap.String("payment_ref", payment.PaymentRef), zap.String("payout_id", payment.Execution.CardPayoutRef))
+	payment.Execution = exec
+
+	plan := ensureExecutionPlan(payment)
+	if plan != nil {
+		step := ensureExecutionStep(plan, stepCodeCardPayout)
+		step.Description = "Submit card payout"
+		step.Amount = cloneMoney(amount)
+		if masked := strings.TrimSpace(card.MaskedPan); masked != "" {
+			step.DestinationRef = masked
+		}
+		if exec.CardPayoutRef != "" {
+			step.TransferRef = exec.CardPayoutRef
+		}
+		updateExecutionPlanTotalNetworkFee(plan)
+	}
+
+	feeMoney := (*moneyv1.Money)(nil)
+	if payment.LastQuote != nil {
+		feeMoney = payment.LastQuote.ExpectedFeeTotal
+	}
+	if feeMoney != nil && strings.TrimSpace(feeMoney.GetAmount()) != "" {
+		if strings.TrimSpace(feeMoney.GetCurrency()) == "" {
+			return merrors.InvalidArgument("card payout: fee currency is required")
+		}
+		feeDecimal, err := decimalFromMoney(feeMoney)
+		if err != nil {
+			return err
+		}
+		if feeDecimal.IsPositive() {
+			if !s.deps.gateway.available() {
+				s.logger.Warn("card fee aborted: chain gateway unavailable")
+				return merrors.InvalidArgument("card payout: chain gateway unavailable")
+			}
+			sourceWallet := intent.Source.ManagedWallet
+			if sourceWallet == nil || strings.TrimSpace(sourceWallet.ManagedWalletRef) == "" {
+				return merrors.InvalidArgument("card payout: source managed wallet is required")
+			}
+			route, err := s.cardRoute(defaultCardGateway)
+			if err != nil {
+				return err
+			}
+			feeWalletRef := strings.TrimSpace(route.FeeWalletRef)
+			if feeWalletRef == "" {
+				return merrors.InvalidArgument("card payout: fee wallet ref is required when fee exists")
+			}
+			feeReq := &chainv1.SubmitTransferRequest{
+				IdempotencyKey:  payment.IdempotencyKey + ":card:fee",
+				OrganizationRef: payment.OrganizationRef.Hex(),
+				SourceWalletRef: strings.TrimSpace(sourceWallet.ManagedWalletRef),
+				Destination: &chainv1.TransferDestination{
+					Destination: &chainv1.TransferDestination_ManagedWalletRef{ManagedWalletRef: feeWalletRef},
+				},
+				Amount:          feeMoney,
+				Metadata:        cloneMetadata(payment.Metadata),
+				ClientReference: payment.PaymentRef,
+			}
+			feeResp, feeErr := s.deps.gateway.client.SubmitTransfer(ctx, feeReq)
+			if feeErr != nil {
+				s.logger.Warn("card fee transfer failed", zap.Error(feeErr), zap.String("payment_ref", payment.PaymentRef))
+				return feeErr
+			}
+			if feeResp != nil && feeResp.GetTransfer() != nil {
+				exec.FeeTransferRef = strings.TrimSpace(feeResp.GetTransfer().GetTransferRef())
+			}
+			s.logger.Info("card fee transfer submitted", zap.String("payment_ref", payment.PaymentRef), zap.String("transfer_ref", exec.FeeTransferRef))
+
+			if plan != nil {
+				step := ensureExecutionStep(plan, stepCodeFeeTransfer)
+				step.Description = "Transfer fee to fee wallet"
+				step.Amount = cloneMoney(feeMoney)
+				step.SourceWalletRef = strings.TrimSpace(sourceWallet.ManagedWalletRef)
+				step.DestinationRef = feeWalletRef
+				step.TransferRef = exec.FeeTransferRef
+				updateExecutionPlanTotalNetworkFee(plan)
+			}
+		}
+	}
+
+	s.logger.Info("card payout submitted", zap.String("payment_ref", payment.PaymentRef), zap.String("payout_id", exec.CardPayoutRef))
 
 	return nil
 }
@@ -250,3 +495,147 @@ func applyCardPayoutUpdate(payment *model.Payment, payout *mntxv1.CardPayoutStat
 		// leave as-is for pending/unspecified
 	}
 }
+
+func cardPayoutAmount(payment *model.Payment) (*moneyv1.Money, error) {
+	if payment == nil {
+		return nil, merrors.InvalidArgument("payment is required")
+	}
+	amount := cloneMoney(payment.Intent.Amount)
+	if payment.LastQuote != nil {
+		settlement := payment.LastQuote.ExpectedSettlementAmount
+		if settlement != nil && strings.TrimSpace(settlement.GetAmount()) != "" && strings.TrimSpace(settlement.GetCurrency()) != "" {
+			amount = cloneMoney(settlement)
+		}
+	}
+	if amount == nil || strings.TrimSpace(amount.GetAmount()) == "" || strings.TrimSpace(amount.GetCurrency()) == "" {
+		return nil, merrors.InvalidArgument("card payout: amount is required")
+	}
+	return amount, nil
+}
+
+func (s *Service) estimateTransferNetworkFee(ctx context.Context, sourceWalletRef string, destination *chainv1.TransferDestination, amount *moneyv1.Money) (*moneyv1.Money, error) {
+	if !s.deps.gateway.available() {
+		return nil, merrors.InvalidArgument("chain gateway unavailable")
+	}
+	sourceWalletRef = strings.TrimSpace(sourceWalletRef)
+	if sourceWalletRef == "" {
+		return nil, merrors.InvalidArgument("source wallet ref is required")
+	}
+	if amount == nil || strings.TrimSpace(amount.GetAmount()) == "" || strings.TrimSpace(amount.GetCurrency()) == "" {
+		return nil, merrors.InvalidArgument("amount is required")
+	}
+
+	resp, err := s.deps.gateway.client.EstimateTransferFee(ctx, &chainv1.EstimateTransferFeeRequest{
+		SourceWalletRef: sourceWalletRef,
+		Destination:     destination,
+		Amount:          cloneMoney(amount),
+	})
+	if err != nil {
+		s.logger.Warn("chain gateway fee estimation failed", zap.Error(err), zap.String("source_wallet_ref", sourceWalletRef))
+		return nil, merrors.Internal("chain_gateway_fee_estimation_failed")
+	}
+	if resp == nil {
+		s.logger.Warn("chain gateway fee estimation returned empty response", zap.String("source_wallet_ref", sourceWalletRef))
+		return nil, merrors.Internal("chain_gateway_fee_estimation_failed")
+	}
+	fee := resp.GetNetworkFee()
+	if fee == nil || strings.TrimSpace(fee.GetAmount()) == "" || strings.TrimSpace(fee.GetCurrency()) == "" {
+		s.logger.Warn("chain gateway fee estimation missing network fee", zap.String("source_wallet_ref", sourceWalletRef))
+		return nil, merrors.Internal("chain_gateway_fee_estimation_failed")
+	}
+	return cloneMoney(fee), nil
+}
+
+func sumNetworkFees(fees ...*moneyv1.Money) (decimal.Decimal, string, error) {
+	total := decimal.Zero
+	currency := ""
+	for _, fee := range fees {
+		if fee == nil {
+			continue
+		}
+		amount := strings.TrimSpace(fee.GetAmount())
+		feeCurrency := strings.TrimSpace(fee.GetCurrency())
+		if amount == "" || feeCurrency == "" {
+			return decimal.Zero, "", merrors.InvalidArgument("network fee is required")
+		}
+		value, err := decimalFromMoney(fee)
+		if err != nil {
+			return decimal.Zero, "", err
+		}
+		if currency == "" {
+			currency = feeCurrency
+		} else if !strings.EqualFold(currency, feeCurrency) {
+			return decimal.Zero, "", merrors.InvalidArgument("network fee currency mismatch")
+		}
+		total = total.Add(value)
+	}
+	return total, currency, nil
+}
+
+func ensureExecutionPlan(payment *model.Payment) *model.ExecutionPlan {
+	if payment == nil {
+		return nil
+	}
+	if payment.ExecutionPlan == nil {
+		payment.ExecutionPlan = &model.ExecutionPlan{}
+	}
+	return payment.ExecutionPlan
+}
+
+func ensureExecutionStep(plan *model.ExecutionPlan, code string) *model.ExecutionStep {
+	if plan == nil {
+		return nil
+	}
+	code = strings.TrimSpace(code)
+	if code == "" {
+		return nil
+	}
+	for _, step := range plan.Steps {
+		if step == nil {
+			continue
+		}
+		if strings.EqualFold(step.Code, code) {
+			if step.Code == "" {
+				step.Code = code
+			}
+			return step
+		}
+	}
+	step := &model.ExecutionStep{Code: code}
+	plan.Steps = append(plan.Steps, step)
+	return step
+}
+
+func updateExecutionPlanTotalNetworkFee(plan *model.ExecutionPlan) {
+	if plan == nil {
+		return
+	}
+	total := decimal.Zero
+	currency := ""
+	hasFee := false
+	for _, step := range plan.Steps {
+		if step == nil || step.NetworkFee == nil {
+			continue
+		}
+		fee := step.NetworkFee
+		if strings.TrimSpace(fee.GetAmount()) == "" || strings.TrimSpace(fee.GetCurrency()) == "" {
+			continue
+		}
+		if currency == "" {
+			currency = strings.TrimSpace(fee.GetCurrency())
+		} else if !strings.EqualFold(currency, fee.GetCurrency()) {
+			continue
+		}
+		value, err := decimalFromMoney(fee)
+		if err != nil {
+			continue
+		}
+		total = total.Add(value)
+		hasFee = true
+	}
+	if !hasFee || currency == "" {
+		plan.TotalNetworkFee = nil
+		return
+	}
+	plan.TotalNetworkFee = makeMoney(currency, total)
+}

api/payments/orchestrator/internal/service/orchestrator/card_payout_test.go

@@ -0,0 +1,407 @@
+package orchestrator
+
+import (
+	"context"
+	"strings"
+	"testing"
+
+	chainclient "github.com/tech/sendico/gateway/chain/client"
+	mntxclient "github.com/tech/sendico/gateway/mntx/client"
+	"github.com/tech/sendico/payments/orchestrator/storage/model"
+	mo "github.com/tech/sendico/pkg/model"
+	moneyv1 "github.com/tech/sendico/pkg/proto/common/money/v1"
+	chainv1 "github.com/tech/sendico/pkg/proto/gateway/chain/v1"
+	mntxv1 "github.com/tech/sendico/pkg/proto/gateway/mntx/v1"
+	orchestratorv1 "github.com/tech/sendico/pkg/proto/payments/orchestrator/v1"
+	"go.mongodb.org/mongo-driver/bson/primitive"
+	"go.uber.org/zap"
+)
+
+func TestSubmitCardFundingTransfers_PlansTopUpAndFunding(t *testing.T) {
+	ctx := context.Background()
+
+	const (
+		sourceWalletRef = "wallet-src"
+		feeWalletRef    = "wallet-fee"
+		fundingAddress  = "0xfunding"
+	)
+
+	var estimateCalls []*chainv1.EstimateTransferFeeRequest
+	var computeCalls []*chainv1.ComputeGasTopUpRequest
+	var ensureCalls []*chainv1.EnsureGasTopUpRequest
+	var submitCalls []*chainv1.SubmitTransferRequest
+
+	gateway := &chainclient.Fake{
+		EstimateTransferFeeFn: func(ctx context.Context, req *chainv1.EstimateTransferFeeRequest) (*chainv1.EstimateTransferFeeResponse, error) {
+			estimateCalls = append(estimateCalls, req)
+			dest := req.GetDestination()
+			if req.GetSourceWalletRef() == feeWalletRef {
+				return &chainv1.EstimateTransferFeeResponse{
+					NetworkFee: &moneyv1.Money{Currency: "ETH", Amount: "0.005"},
+				}, nil
+			}
+			if dest != nil && strings.TrimSpace(dest.GetExternalAddress()) != "" {
+				return &chainv1.EstimateTransferFeeResponse{
+					NetworkFee: &moneyv1.Money{Currency: "ETH", Amount: "0.01"},
+				}, nil
+			}
+			return &chainv1.EstimateTransferFeeResponse{
+				NetworkFee: &moneyv1.Money{Currency: "ETH", Amount: "0.02"},
+			}, nil
+		},
+		ComputeGasTopUpFn: func(ctx context.Context, req *chainv1.ComputeGasTopUpRequest) (*chainv1.ComputeGasTopUpResponse, error) {
+			computeCalls = append(computeCalls, req)
+			return &chainv1.ComputeGasTopUpResponse{
+				TopupAmount: &moneyv1.Money{Currency: "ETH", Amount: "0.025"},
+			}, nil
+		},
+		EnsureGasTopUpFn: func(ctx context.Context, req *chainv1.EnsureGasTopUpRequest) (*chainv1.EnsureGasTopUpResponse, error) {
+			ensureCalls = append(ensureCalls, req)
+			return &chainv1.EnsureGasTopUpResponse{
+				TopupAmount: &moneyv1.Money{Currency: "ETH", Amount: "0.025"},
+				Transfer:    &chainv1.Transfer{TransferRef: req.GetIdempotencyKey()},
+			}, nil
+		},
+		SubmitTransferFn: func(ctx context.Context, req *chainv1.SubmitTransferRequest) (*chainv1.SubmitTransferResponse, error) {
+			submitCalls = append(submitCalls, req)
+			return &chainv1.SubmitTransferResponse{
+				Transfer: &chainv1.Transfer{TransferRef: req.GetIdempotencyKey()},
+			}, nil
+		},
+	}
+
+	svc := &Service{
+		logger: zap.NewNop(),
+		deps: serviceDependencies{
+			gateway: gatewayDependency{client: gateway},
+			cardRoutes: map[string]CardGatewayRoute{
+				defaultCardGateway: {
+					FundingAddress: fundingAddress,
+					FeeWalletRef:   feeWalletRef,
+				},
+			},
+		},
+	}
+
+	payment := &model.Payment{
+		PaymentRef:            "pay-1",
+		IdempotencyKey:        "pay-1",
+		OrganizationBoundBase: mo.OrganizationBoundBase{OrganizationRef: primitive.NewObjectID()},
+		Intent: model.PaymentIntent{
+			Kind: model.PaymentKindPayout,
+			Source: model.PaymentEndpoint{
+				Type: model.EndpointTypeManagedWallet,
+				ManagedWallet: &model.ManagedWalletEndpoint{
+					ManagedWalletRef: sourceWalletRef,
+				},
+			},
+			Destination: model.PaymentEndpoint{
+				Type: model.EndpointTypeCard,
+				Card: &model.CardEndpoint{
+					MaskedPan: "4111",
+				},
+			},
+			Amount: &moneyv1.Money{Currency: "USDT", Amount: "5"},
+		},
+	}
+
+	quote := &orchestratorv1.PaymentQuote{
+		ExpectedFeeTotal: &moneyv1.Money{Currency: "USDT", Amount: "0.35"},
+	}
+
+	if err := svc.submitCardFundingTransfers(ctx, payment, quote); err != nil {
+		t.Fatalf("submitCardFundingTransfers error: %v", err)
+	}
+
+	if len(estimateCalls) != 4 {
+		t.Fatalf("expected 4 fee estimates, got %d", len(estimateCalls))
+	}
+	if len(computeCalls) != 1 {
+		t.Fatalf("expected 1 gas top-up compute call, got %d", len(computeCalls))
+	}
+	if len(ensureCalls) != 1 {
+		t.Fatalf("expected 1 gas top-up ensure call, got %d", len(ensureCalls))
+	}
+	if len(submitCalls) != 1 {
+		t.Fatalf("expected 1 transfer submission, got %d", len(submitCalls))
+	}
+
+	computeCall := computeCalls[0]
+	if computeCall.GetWalletRef() != sourceWalletRef {
+		t.Fatalf("gas top-up compute wallet mismatch: %s", computeCall.GetWalletRef())
+	}
+	if computeCall.GetEstimatedTotalFee().GetCurrency() != "ETH" || computeCall.GetEstimatedTotalFee().GetAmount() != "0.03" {
+		t.Fatalf("gas top-up compute fee mismatch: %s %s", computeCall.GetEstimatedTotalFee().GetCurrency(), computeCall.GetEstimatedTotalFee().GetAmount())
+	}
+
+	ensureCall := ensureCalls[0]
+	if ensureCall.GetSourceWalletRef() != feeWalletRef {
+		t.Fatalf("gas top-up source wallet mismatch: %s", ensureCall.GetSourceWalletRef())
+	}
+	if ensureCall.GetTargetWalletRef() != sourceWalletRef {
+		t.Fatalf("gas top-up destination mismatch: %s", ensureCall.GetTargetWalletRef())
+	}
+	if ensureCall.GetEstimatedTotalFee().GetCurrency() != "ETH" || ensureCall.GetEstimatedTotalFee().GetAmount() != "0.03" {
+		t.Fatalf("gas top-up ensure fee mismatch: %s %s", ensureCall.GetEstimatedTotalFee().GetCurrency(), ensureCall.GetEstimatedTotalFee().GetAmount())
+	}
+
+	fundCall := findSubmitCall(t, submitCalls, "pay-1:card:fund")
+	if fundCall.GetDestination().GetExternalAddress() != fundingAddress {
+		t.Fatalf("funding destination mismatch: %s", fundCall.GetDestination().GetExternalAddress())
+	}
+	if fundCall.GetAmount().GetCurrency() != "USDT" || fundCall.GetAmount().GetAmount() != "5" {
+		t.Fatalf("funding amount mismatch: %s %s", fundCall.GetAmount().GetCurrency(), fundCall.GetAmount().GetAmount())
+	}
+
+	if payment.Execution == nil || payment.Execution.ChainTransferRef != "pay-1:card:fund" {
+		t.Fatalf("expected funding transfer ref recorded, got %v", payment.Execution)
+	}
+
+	plan := payment.ExecutionPlan
+	if plan == nil {
+		t.Fatal("expected execution plan to be populated")
+	}
+	gasStep := findExecutionStep(t, plan, stepCodeGasTopUp)
+	if gasStep.Amount.GetAmount() != "0.025" || gasStep.Amount.GetCurrency() != "ETH" {
+		t.Fatalf("gas step amount mismatch: %s %s", gasStep.Amount.GetCurrency(), gasStep.Amount.GetAmount())
+	}
+	if gasStep.NetworkFee.GetAmount() != "0.005" || gasStep.NetworkFee.GetCurrency() != "ETH" {
+		t.Fatalf("gas step fee mismatch: %s %s", gasStep.NetworkFee.GetCurrency(), gasStep.NetworkFee.GetAmount())
+	}
+	if gasStep.TransferRef != "pay-1:card:gas" {
+		t.Fatalf("expected gas step transfer ref to be set, got %s", gasStep.TransferRef)
+	}
+
+	fundStep := findExecutionStep(t, plan, stepCodeFundingTransfer)
+	if fundStep.NetworkFee.GetAmount() != "0.01" || fundStep.NetworkFee.GetCurrency() != "ETH" {
+		t.Fatalf("funding step fee mismatch: %s %s", fundStep.NetworkFee.GetCurrency(), fundStep.NetworkFee.GetAmount())
+	}
+	if fundStep.TransferRef != "pay-1:card:fund" {
+		t.Fatalf("funding step transfer ref mismatch: %s", fundStep.TransferRef)
+	}
+
+	cardStep := findExecutionStep(t, plan, stepCodeCardPayout)
+	if cardStep.Amount.GetAmount() != "5" || cardStep.Amount.GetCurrency() != "USDT" {
+		t.Fatalf("card step amount mismatch: %s %s", cardStep.Amount.GetCurrency(), cardStep.Amount.GetAmount())
+	}
+
+	feeStep := findExecutionStep(t, plan, stepCodeFeeTransfer)
+	if feeStep.Amount.GetAmount() != "0.35" || feeStep.Amount.GetCurrency() != "USDT" {
+		t.Fatalf("fee step amount mismatch: %s %s", feeStep.Amount.GetCurrency(), feeStep.Amount.GetAmount())
+	}
+	if feeStep.NetworkFee.GetAmount() != "0.02" || feeStep.NetworkFee.GetCurrency() != "ETH" {
+		t.Fatalf("fee step network fee mismatch: %s %s", feeStep.NetworkFee.GetCurrency(), feeStep.NetworkFee.GetAmount())
+	}
+	if feeStep.TransferRef != "" {
+		t.Fatalf("expected fee step transfer ref to be empty before payout, got %s", feeStep.TransferRef)
+	}
+
+	if plan.TotalNetworkFee == nil || plan.TotalNetworkFee.GetAmount() != "0.035" || plan.TotalNetworkFee.GetCurrency() != "ETH" {
+		t.Fatalf("total network fee mismatch: %v", plan.TotalNetworkFee)
+	}
+}
+
+func TestSubmitCardPayout_UsesSettlementAmountAndTransfersFee(t *testing.T) {
+	ctx := context.Background()
+
+	const (
+		sourceWalletRef = "wallet-src"
+		feeWalletRef    = "wallet-fee"
+	)
+
+	var payoutReq *mntxv1.CardPayoutRequest
+	var submitCalls []*chainv1.SubmitTransferRequest
+
+	gateway := &chainclient.Fake{
+		SubmitTransferFn: func(ctx context.Context, req *chainv1.SubmitTransferRequest) (*chainv1.SubmitTransferResponse, error) {
+			submitCalls = append(submitCalls, req)
+			return &chainv1.SubmitTransferResponse{
+				Transfer: &chainv1.Transfer{TransferRef: "fee-transfer"},
+			}, nil
+		},
+	}
+	mntx := &mntxclient.Fake{
+		CreateCardPayoutFn: func(ctx context.Context, req *mntxv1.CardPayoutRequest) (*mntxv1.CardPayoutResponse, error) {
+			payoutReq = req
+			return &mntxv1.CardPayoutResponse{
+				Payout: &mntxv1.CardPayoutState{
+					PayoutId: "payout-1",
+					Status:   mntxv1.PayoutStatus_PAYOUT_STATUS_PENDING,
+				},
+			}, nil
+		},
+	}
+
+	svc := &Service{
+		logger: zap.NewNop(),
+		deps: serviceDependencies{
+			gateway: gatewayDependency{client: gateway},
+			mntx:    mntxDependency{client: mntx},
+			cardRoutes: map[string]CardGatewayRoute{
+				defaultCardGateway: {
+					FundingAddress: "0xfunding",
+					FeeWalletRef:   feeWalletRef,
+				},
+			},
+		},
+	}
+
+	payment := &model.Payment{
+		PaymentRef:            "pay-2",
+		IdempotencyKey:        "pay-2",
+		OrganizationBoundBase: mo.OrganizationBoundBase{OrganizationRef: primitive.NewObjectID()},
+		Intent: model.PaymentIntent{
+			Kind: model.PaymentKindPayout,
+			Source: model.PaymentEndpoint{
+				Type: model.EndpointTypeManagedWallet,
+				ManagedWallet: &model.ManagedWalletEndpoint{
+					ManagedWalletRef: sourceWalletRef,
+				},
+			},
+			Destination: model.PaymentEndpoint{
+				Type: model.EndpointTypeCard,
+				Card: &model.CardEndpoint{
+					Pan:        "5536913762657597",
+					Cardholder: "Stephan",
+				},
+			},
+			Amount: &moneyv1.Money{Currency: "USDT", Amount: "5"},
+		},
+		LastQuote: &model.PaymentQuoteSnapshot{
+			ExpectedSettlementAmount: &moneyv1.Money{Currency: "RUB", Amount: "392.30"},
+			ExpectedFeeTotal:         &moneyv1.Money{Currency: "USDT", Amount: "0.35"},
+		},
+	}
+
+	if err := svc.submitCardPayout(ctx, payment); err != nil {
+		t.Fatalf("submitCardPayout error: %v", err)
+	}
+
+	if payoutReq == nil {
+		t.Fatal("expected card payout request to be sent")
+	}
+	if payoutReq.GetCurrency() != "RUB" || payoutReq.GetAmountMinor() != 39230 {
+		t.Fatalf("payout request amount mismatch: %s %d", payoutReq.GetCurrency(), payoutReq.GetAmountMinor())
+	}
+
+	if payment.Execution == nil || payment.Execution.CardPayoutRef != "payout-1" {
+		t.Fatalf("expected card payout ref recorded, got %v", payment.Execution)
+	}
+	if payment.Execution.FeeTransferRef != "fee-transfer" {
+		t.Fatalf("expected fee transfer ref recorded, got %v", payment.Execution)
+	}
+
+	if len(submitCalls) != 1 {
+		t.Fatalf("expected 1 fee transfer submission, got %d", len(submitCalls))
+	}
+	feeCall := submitCalls[0]
+	if feeCall.GetSourceWalletRef() != sourceWalletRef {
+		t.Fatalf("fee transfer source mismatch: %s", feeCall.GetSourceWalletRef())
+	}
+	if feeCall.GetDestination().GetManagedWalletRef() != feeWalletRef {
+		t.Fatalf("fee transfer destination mismatch: %s", feeCall.GetDestination().GetManagedWalletRef())
+	}
+
+	plan := payment.ExecutionPlan
+	if plan == nil {
+		t.Fatal("expected execution plan to be populated")
+	}
+	cardStep := findExecutionStep(t, plan, stepCodeCardPayout)
+	if cardStep.TransferRef != "payout-1" {
+		t.Fatalf("card step transfer ref mismatch: %s", cardStep.TransferRef)
+	}
+	if cardStep.Amount.GetAmount() != "392.30" || cardStep.Amount.GetCurrency() != "RUB" {
+		t.Fatalf("card step amount mismatch: %s %s", cardStep.Amount.GetCurrency(), cardStep.Amount.GetAmount())
+	}
+
+	feeStep := findExecutionStep(t, plan, stepCodeFeeTransfer)
+	if feeStep.TransferRef != "fee-transfer" {
+		t.Fatalf("fee step transfer ref mismatch: %s", feeStep.TransferRef)
+	}
+	if feeStep.Amount.GetAmount() != "0.35" || feeStep.Amount.GetCurrency() != "USDT" {
+		t.Fatalf("fee step amount mismatch: %s %s", feeStep.Amount.GetCurrency(), feeStep.Amount.GetAmount())
+	}
+}
+
+func TestSubmitCardFundingTransfers_RequiresFeeWalletRef(t *testing.T) {
+	ctx := context.Background()
+
+	gateway := &chainclient.Fake{
+		EstimateTransferFeeFn: func(ctx context.Context, req *chainv1.EstimateTransferFeeRequest) (*chainv1.EstimateTransferFeeResponse, error) {
+			return &chainv1.EstimateTransferFeeResponse{
+				NetworkFee: &moneyv1.Money{Currency: "ETH", Amount: "0.01"},
+			}, nil
+		},
+	}
+
+	svc := &Service{
+		logger: zap.NewNop(),
+		deps: serviceDependencies{
+			gateway: gatewayDependency{client: gateway},
+			cardRoutes: map[string]CardGatewayRoute{
+				defaultCardGateway: {
+					FundingAddress: "0xfunding",
+				},
+			},
+		},
+	}
+
+	payment := &model.Payment{
+		PaymentRef:            "pay-3",
+		IdempotencyKey:        "pay-3",
+		OrganizationBoundBase: mo.OrganizationBoundBase{OrganizationRef: primitive.NewObjectID()},
+		Intent: model.PaymentIntent{
+			Kind: model.PaymentKindPayout,
+			Source: model.PaymentEndpoint{
+				Type: model.EndpointTypeManagedWallet,
+				ManagedWallet: &model.ManagedWalletEndpoint{
+					ManagedWalletRef: "wallet-src",
+				},
+			},
+			Destination: model.PaymentEndpoint{
+				Type: model.EndpointTypeCard,
+				Card: &model.CardEndpoint{
+					MaskedPan: "4111",
+				},
+			},
+			Amount: &moneyv1.Money{Currency: "USDT", Amount: "5"},
+		},
+	}
+
+	quote := &orchestratorv1.PaymentQuote{
+		ExpectedFeeTotal: &moneyv1.Money{Currency: "USDT", Amount: "0.35"},
+	}
+
+	err := svc.submitCardFundingTransfers(ctx, payment, quote)
+	if err == nil {
+		t.Fatal("expected error for missing fee wallet ref")
+	}
+	if !strings.Contains(err.Error(), "fee wallet ref") {
+		t.Fatalf("unexpected error: %v", err)
+	}
+}
+
+func findSubmitCall(t *testing.T, calls []*chainv1.SubmitTransferRequest, idempotencyKey string) *chainv1.SubmitTransferRequest {
+	t.Helper()
+	for _, call := range calls {
+		if call.GetIdempotencyKey() == idempotencyKey {
+			return call
+		}
+	}
+	t.Fatalf("missing submit transfer call for %s", idempotencyKey)
+	return nil
+}
+
+func findExecutionStep(t *testing.T, plan *model.ExecutionPlan, code string) *model.ExecutionStep {
+	t.Helper()
+	if plan == nil {
+		t.Fatal("execution plan is nil")
+	}
+	for _, step := range plan.Steps {
+		if step != nil && strings.EqualFold(step.Code, code) {
+			return step
+		}
+	}
+	t.Fatalf("missing execution step %s", code)
+	return nil
+}

api/payments/orchestrator/internal/service/orchestrator/command_factory.go

@@ -61,6 +61,13 @@ func (f *paymentCommandFactory) QuotePayment() *quotePaymentCommand {
 	}
 }
 
+func (f *paymentCommandFactory) QuotePayments() *quotePaymentsCommand {
+	return &quotePaymentsCommand{
+		engine: f.engine,
+		logger: f.logger.Named("quote_payments"),
+	}
+}
+
 func (f *paymentCommandFactory) InitiatePayment() *initiatePaymentCommand {
 	return &initiatePaymentCommand{
 		engine: f.engine,
@@ -68,6 +75,13 @@ func (f *paymentCommandFactory) InitiatePayment() *initiatePaymentCommand {
 	}
 }
 
+func (f *paymentCommandFactory) InitiatePayments() *initiatePaymentsCommand {
+	return &initiatePaymentsCommand{
+		engine: f.engine,
+		logger: f.logger.Named("initiate_payments"),
+	}
+}
+
 func (f *paymentCommandFactory) CancelPayment() *cancelPaymentCommand {
 	return &cancelPaymentCommand{
 		engine: f.engine,

api/payments/orchestrator/internal/service/orchestrator/convert.go

@@ -5,9 +5,7 @@ import (
 	"time"
 
 	"github.com/tech/sendico/payments/orchestrator/storage/model"
-	"github.com/tech/sendico/pkg/merrors"
 	fxv1 "github.com/tech/sendico/pkg/proto/common/fx/v1"
-	paginationv1 "github.com/tech/sendico/pkg/proto/common/pagination/v1"
 	chainv1 "github.com/tech/sendico/pkg/proto/gateway/chain/v1"
 	oraclev1 "github.com/tech/sendico/pkg/proto/oracle/v1"
 	orchestratorv1 "github.com/tech/sendico/pkg/proto/payments/orchestrator/v1"
@@ -20,13 +18,14 @@ func intentFromProto(src *orchestratorv1.PaymentIntent) model.PaymentIntent {
 		return model.PaymentIntent{}
 	}
 	intent := model.PaymentIntent{
-		Kind:        modelKindFromProto(src.GetKind()),
-		Source:      endpointFromProto(src.GetSource()),
-		Destination: endpointFromProto(src.GetDestination()),
-		Amount:      cloneMoney(src.GetAmount()),
-		RequiresFX:  src.GetRequiresFx(),
-		FeePolicy:   src.GetFeePolicy(),
-		Attributes:  cloneMetadata(src.GetAttributes()),
+		Kind:           modelKindFromProto(src.GetKind()),
+		Source:         endpointFromProto(src.GetSource()),
+		Destination:    endpointFromProto(src.GetDestination()),
+		Amount:         cloneMoney(src.GetAmount()),
+		RequiresFX:     src.GetRequiresFx(),
+		FeePolicy:      src.GetFeePolicy(),
+		SettlementMode: src.GetSettlementMode(),
+		Attributes:     cloneMetadata(src.GetAttributes()),
 	}
 	if src.GetFx() != nil {
 		intent.FX = fxIntentFromProto(src.GetFx())
@@ -126,6 +125,7 @@ func toProtoPayment(src *model.Payment) *orchestratorv1.Payment {
 		FailureReason:  src.FailureReason,
 		LastQuote:      modelQuoteToProto(src.LastQuote),
 		Execution:      protoExecutionFromModel(src.Execution),
+		ExecutionPlan:  protoExecutionPlanFromModel(src.ExecutionPlan),
 		Metadata:       cloneMetadata(src.Metadata),
 	}
 	if src.CardPayout != nil {
@@ -153,13 +153,14 @@ func toProtoPayment(src *model.Payment) *orchestratorv1.Payment {
 
 func protoIntentFromModel(src model.PaymentIntent) *orchestratorv1.PaymentIntent {
 	intent := &orchestratorv1.PaymentIntent{
-		Kind:        protoKindFromModel(src.Kind),
-		Source:      protoEndpointFromModel(src.Source),
-		Destination: protoEndpointFromModel(src.Destination),
-		Amount:      cloneMoney(src.Amount),
-		RequiresFx:  src.RequiresFX,
-		FeePolicy:   src.FeePolicy,
-		Attributes:  cloneMetadata(src.Attributes),
+		Kind:           protoKindFromModel(src.Kind),
+		Source:         protoEndpointFromModel(src.Source),
+		Destination:    protoEndpointFromModel(src.Destination),
+		Amount:         cloneMoney(src.Amount),
+		RequiresFx:     src.RequiresFX,
+		FeePolicy:      src.FeePolicy,
+		SettlementMode: src.SettlementMode,
+		Attributes:     cloneMetadata(src.Attributes),
 	}
 	if src.FX != nil {
 		intent.Fx = protoFXIntentFromModel(src.FX)
@@ -251,6 +252,41 @@ func protoExecutionFromModel(src *model.ExecutionRefs) *orchestratorv1.Execution
 	}
 }
 
+func protoExecutionStepFromModel(src *model.ExecutionStep) *orchestratorv1.ExecutionStep {
+	if src == nil {
+		return nil
+	}
+	return &orchestratorv1.ExecutionStep{
+		Code:            src.Code,
+		Description:     src.Description,
+		Amount:          cloneMoney(src.Amount),
+		NetworkFee:      cloneMoney(src.NetworkFee),
+		SourceWalletRef: src.SourceWalletRef,
+		DestinationRef:  src.DestinationRef,
+		TransferRef:     src.TransferRef,
+		Metadata:        cloneMetadata(src.Metadata),
+	}
+}
+
+func protoExecutionPlanFromModel(src *model.ExecutionPlan) *orchestratorv1.ExecutionPlan {
+	if src == nil {
+		return nil
+	}
+	steps := make([]*orchestratorv1.ExecutionStep, 0, len(src.Steps))
+	for _, step := range src.Steps {
+		if protoStep := protoExecutionStepFromModel(step); protoStep != nil {
+			steps = append(steps, protoStep)
+		}
+	}
+	if len(steps) == 0 {
+		steps = nil
+	}
+	return &orchestratorv1.ExecutionPlan{
+		Steps:           steps,
+		TotalNetworkFee: cloneMoney(src.TotalNetworkFee),
+	}
+}
+
 func modelQuoteToProto(src *model.PaymentQuoteSnapshot) *orchestratorv1.PaymentQuote {
 	if src == nil {
 		return nil
@@ -411,74 +447,3 @@ func cloneNetworkEstimate(resp *chainv1.EstimateTransferFeeResponse) *chainv1.Es
 	}
 	return nil
 }
-
-func protoFailureToModel(code orchestratorv1.PaymentFailureCode) model.PaymentFailureCode {
-	switch code {
-	case orchestratorv1.PaymentFailureCode_PAYMENT_FAILURE_CODE_BALANCE:
-		return model.PaymentFailureCodeBalance
-	case orchestratorv1.PaymentFailureCode_PAYMENT_FAILURE_CODE_LEDGER:
-		return model.PaymentFailureCodeLedger
-	case orchestratorv1.PaymentFailureCode_PAYMENT_FAILURE_CODE_FX:
-		return model.PaymentFailureCodeFX
-	case orchestratorv1.PaymentFailureCode_PAYMENT_FAILURE_CODE_CHAIN:
-		return model.PaymentFailureCodeChain
-	case orchestratorv1.PaymentFailureCode_PAYMENT_FAILURE_CODE_FEES:
-		return model.PaymentFailureCodeFees
-	case orchestratorv1.PaymentFailureCode_PAYMENT_FAILURE_CODE_POLICY:
-		return model.PaymentFailureCodePolicy
-	default:
-		return model.PaymentFailureCodeUnspecified
-	}
-}
-
-func applyProtoPaymentToModel(src *orchestratorv1.Payment, dst *model.Payment) error {
-	if src == nil || dst == nil {
-		return merrors.InvalidArgument("payment payload is required")
-	}
-	dst.PaymentRef = strings.TrimSpace(src.GetPaymentRef())
-	dst.IdempotencyKey = strings.TrimSpace(src.GetIdempotencyKey())
-	dst.Intent = intentFromProto(src.GetIntent())
-	dst.State = modelStateFromProto(src.GetState())
-	dst.FailureCode = protoFailureToModel(src.GetFailureCode())
-	dst.FailureReason = strings.TrimSpace(src.GetFailureReason())
-	dst.Metadata = cloneMetadata(src.GetMetadata())
-	dst.LastQuote = quoteSnapshotToModel(src.GetLastQuote())
-	dst.Execution = executionFromProto(src.GetExecution())
-	if src.GetCardPayout() != nil {
-		dst.CardPayout = &model.CardPayout{
-			PayoutRef:         strings.TrimSpace(src.GetCardPayout().GetPayoutRef()),
-			ProviderPaymentID: strings.TrimSpace(src.GetCardPayout().GetProviderPaymentId()),
-			Status:            strings.TrimSpace(src.GetCardPayout().GetStatus()),
-			FailureReason:     strings.TrimSpace(src.GetCardPayout().GetFailureReason()),
-			CardCountry:       strings.TrimSpace(src.GetCardPayout().GetCardCountry()),
-			MaskedPan:         strings.TrimSpace(src.GetCardPayout().GetMaskedPan()),
-			ProviderCode:      strings.TrimSpace(src.GetCardPayout().GetProviderCode()),
-			GatewayReference:  strings.TrimSpace(src.GetCardPayout().GetGatewayReference()),
-		}
-	}
-	return nil
-}
-
-func executionFromProto(src *orchestratorv1.ExecutionRefs) *model.ExecutionRefs {
-	if src == nil {
-		return nil
-	}
-	return &model.ExecutionRefs{
-		DebitEntryRef:    strings.TrimSpace(src.GetDebitEntryRef()),
-		CreditEntryRef:   strings.TrimSpace(src.GetCreditEntryRef()),
-		FXEntryRef:       strings.TrimSpace(src.GetFxEntryRef()),
-		ChainTransferRef: strings.TrimSpace(src.GetChainTransferRef()),
-		CardPayoutRef:    strings.TrimSpace(src.GetCardPayoutRef()),
-		FeeTransferRef:   strings.TrimSpace(src.GetFeeTransferRef()),
-	}
-}
-
-func ensurePageRequest(req *orchestratorv1.ListPaymentsRequest) *paginationv1.CursorPageRequest {
-	if req == nil {
-		return &paginationv1.CursorPageRequest{}
-	}
-	if req.GetPage() == nil {
-		return &paginationv1.CursorPageRequest{}
-	}
-	return req.GetPage()
-}

api/payments/orchestrator/internal/service/orchestrator/handlers_commands.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"errors"
 	"strings"
+	"time"
 
 	"github.com/tech/sendico/payments/orchestrator/storage"
 	"github.com/tech/sendico/payments/orchestrator/storage/model"
@@ -66,6 +67,177 @@ func (h *quotePaymentCommand) Execute(ctx context.Context, req *orchestratorv1.Q
 	return gsresponse.Success(&orchestratorv1.QuotePaymentResponse{Quote: quote})
 }
 
+type quotePaymentsCommand struct {
+	engine paymentEngine
+	logger mlogger.Logger
+}
+
+func (h *quotePaymentsCommand) Execute(ctx context.Context, req *orchestratorv1.QuotePaymentsRequest) gsresponse.Responder[orchestratorv1.QuotePaymentsResponse] {
+	if err := h.engine.EnsureRepository(ctx); err != nil {
+		return gsresponse.Unavailable[orchestratorv1.QuotePaymentsResponse](h.logger, mservice.PaymentOrchestrator, err)
+	}
+	if req == nil {
+		return gsresponse.InvalidArgument[orchestratorv1.QuotePaymentsResponse](h.logger, mservice.PaymentOrchestrator, merrors.InvalidArgument("nil request"))
+	}
+	orgRef, orgID, err := validateMetaAndOrgRef(req.GetMeta())
+	if err != nil {
+		return gsresponse.InvalidArgument[orchestratorv1.QuotePaymentsResponse](h.logger, mservice.PaymentOrchestrator, err)
+	}
+	intents := req.GetIntents()
+	if len(intents) == 0 {
+		return gsresponse.InvalidArgument[orchestratorv1.QuotePaymentsResponse](h.logger, mservice.PaymentOrchestrator, merrors.InvalidArgument("intents are required"))
+	}
+
+	baseKey := strings.TrimSpace(req.GetIdempotencyKey())
+	quotes := make([]*orchestratorv1.PaymentQuote, 0, len(intents))
+	expires := make([]time.Time, 0, len(intents))
+	for i, intent := range intents {
+		if err := requireNonNilIntent(intent); err != nil {
+			return gsresponse.InvalidArgument[orchestratorv1.QuotePaymentsResponse](h.logger, mservice.PaymentOrchestrator, err)
+		}
+		quoteReq := &orchestratorv1.QuotePaymentRequest{
+			Meta:           req.GetMeta(),
+			IdempotencyKey: perIntentIdempotencyKey(baseKey, i, len(intents)),
+			Intent:         intent,
+			PreviewOnly:    req.GetPreviewOnly(),
+		}
+		quote, expiresAt, err := h.engine.BuildPaymentQuote(ctx, orgRef, quoteReq)
+		if err != nil {
+			return gsresponse.Auto[orchestratorv1.QuotePaymentsResponse](h.logger, mservice.PaymentOrchestrator, err)
+		}
+		quotes = append(quotes, quote)
+		expires = append(expires, expiresAt)
+	}
+
+	aggregate, err := aggregatePaymentQuotes(quotes)
+	if err != nil {
+		return gsresponse.Auto[orchestratorv1.QuotePaymentsResponse](h.logger, mservice.PaymentOrchestrator, merrors.InternalWrap(err, "quote aggregation failed"))
+	}
+	expiresAt, ok := minQuoteExpiry(expires)
+	if !ok {
+		return gsresponse.Auto[orchestratorv1.QuotePaymentsResponse](h.logger, mservice.PaymentOrchestrator, merrors.Internal("quote expiry missing"))
+	}
+
+	quoteRef := ""
+	if !req.GetPreviewOnly() {
+		quotesStore, err := ensureQuotesStore(h.engine.Repository())
+		if err != nil {
+			return gsresponse.Unavailable[orchestratorv1.QuotePaymentsResponse](h.logger, mservice.PaymentOrchestrator, err)
+		}
+		quoteRef = primitive.NewObjectID().Hex()
+		record := &model.PaymentQuoteRecord{
+			QuoteRef:  quoteRef,
+			Intents:   intentsFromProto(intents),
+			Quotes:    quoteSnapshotsFromProto(quotes),
+			ExpiresAt: expiresAt,
+		}
+		record.SetID(primitive.NewObjectID())
+		record.SetOrganizationRef(orgID)
+		if err := quotesStore.Create(ctx, record); err != nil {
+			return gsresponse.Auto[orchestratorv1.QuotePaymentsResponse](h.logger, mservice.PaymentOrchestrator, err)
+		}
+		h.logger.Info("stored payment quotes", zap.String("quote_ref", quoteRef), zap.String("org_ref", orgID.Hex()))
+	}
+
+	return gsresponse.Success(&orchestratorv1.QuotePaymentsResponse{
+		QuoteRef:  quoteRef,
+		Aggregate: aggregate,
+		Quotes:    quotes,
+	})
+}
+
+type initiatePaymentsCommand struct {
+	engine paymentEngine
+	logger mlogger.Logger
+}
+
+func (h *initiatePaymentsCommand) Execute(ctx context.Context, req *orchestratorv1.InitiatePaymentsRequest) gsresponse.Responder[orchestratorv1.InitiatePaymentsResponse] {
+	if err := h.engine.EnsureRepository(ctx); err != nil {
+		return gsresponse.Unavailable[orchestratorv1.InitiatePaymentsResponse](h.logger, mservice.PaymentOrchestrator, err)
+	}
+	if req == nil {
+		return gsresponse.InvalidArgument[orchestratorv1.InitiatePaymentsResponse](h.logger, mservice.PaymentOrchestrator, merrors.InvalidArgument("nil request"))
+	}
+	_, orgID, err := validateMetaAndOrgRef(req.GetMeta())
+	if err != nil {
+		return gsresponse.InvalidArgument[orchestratorv1.InitiatePaymentsResponse](h.logger, mservice.PaymentOrchestrator, err)
+	}
+	idempotencyKey, err := requireIdempotencyKey(req.GetIdempotencyKey())
+	if err != nil {
+		return gsresponse.InvalidArgument[orchestratorv1.InitiatePaymentsResponse](h.logger, mservice.PaymentOrchestrator, err)
+	}
+	quoteRef := strings.TrimSpace(req.GetQuoteRef())
+	if quoteRef == "" {
+		return gsresponse.InvalidArgument[orchestratorv1.InitiatePaymentsResponse](h.logger, mservice.PaymentOrchestrator, merrors.InvalidArgument("quote_ref is required"))
+	}
+
+	quotesStore, err := ensureQuotesStore(h.engine.Repository())
+	if err != nil {
+		return gsresponse.Unavailable[orchestratorv1.InitiatePaymentsResponse](h.logger, mservice.PaymentOrchestrator, err)
+	}
+	record, err := quotesStore.GetByRef(ctx, orgID, quoteRef)
+	if err != nil {
+		if errors.Is(err, storage.ErrQuoteNotFound) {
+			return gsresponse.FailedPrecondition[orchestratorv1.InitiatePaymentsResponse](h.logger, mservice.PaymentOrchestrator, "quote_not_found", merrors.InvalidArgument("quote_ref not found or expired"))
+		}
+		return gsresponse.Auto[orchestratorv1.InitiatePaymentsResponse](h.logger, mservice.PaymentOrchestrator, err)
+	}
+
+	intents := record.Intents
+	quotes := record.Quotes
+	if len(intents) == 0 && record.Intent.Kind != "" && record.Intent.Kind != model.PaymentKindUnspecified {
+		intents = []model.PaymentIntent{record.Intent}
+	}
+	if len(quotes) == 0 && record.Quote != nil {
+		quotes = []*model.PaymentQuoteSnapshot{record.Quote}
+	}
+	if len(intents) == 0 || len(quotes) == 0 || len(intents) != len(quotes) {
+		return gsresponse.InvalidArgument[orchestratorv1.InitiatePaymentsResponse](h.logger, mservice.PaymentOrchestrator, merrors.InvalidArgument("stored quote payload is incomplete"))
+	}
+
+	store, err := ensurePaymentsStore(h.engine.Repository())
+	if err != nil {
+		return gsresponse.Unavailable[orchestratorv1.InitiatePaymentsResponse](h.logger, mservice.PaymentOrchestrator, err)
+	}
+
+	payments := make([]*orchestratorv1.Payment, 0, len(intents))
+	for i := range intents {
+		intentProto := protoIntentFromModel(intents[i])
+		if err := requireNonNilIntent(intentProto); err != nil {
+			return gsresponse.InvalidArgument[orchestratorv1.InitiatePaymentsResponse](h.logger, mservice.PaymentOrchestrator, err)
+		}
+		quoteProto := modelQuoteToProto(quotes[i])
+		if quoteProto == nil {
+			return gsresponse.InvalidArgument[orchestratorv1.InitiatePaymentsResponse](h.logger, mservice.PaymentOrchestrator, merrors.InvalidArgument("stored quote is empty"))
+		}
+		quoteProto.QuoteRef = quoteRef
+
+		perKey := perIntentIdempotencyKey(idempotencyKey, i, len(intents))
+		if existing, err := getPaymentByIdempotencyKey(ctx, store, orgID, perKey); err == nil && existing != nil {
+			payments = append(payments, toProtoPayment(existing))
+			continue
+		} else if err != nil && !errors.Is(err, storage.ErrPaymentNotFound) {
+			return gsresponse.Auto[orchestratorv1.InitiatePaymentsResponse](h.logger, mservice.PaymentOrchestrator, err)
+		}
+
+		entity := newPayment(orgID, intentProto, perKey, req.GetMetadata(), quoteProto)
+		if err = store.Create(ctx, entity); err != nil {
+			if errors.Is(err, storage.ErrDuplicatePayment) {
+				return gsresponse.Auto[orchestratorv1.InitiatePaymentsResponse](h.logger, mservice.PaymentOrchestrator, merrors.DataConflict("payment already exists"))
+			}
+			return gsresponse.Auto[orchestratorv1.InitiatePaymentsResponse](h.logger, mservice.PaymentOrchestrator, err)
+		}
+
+		if err := h.engine.ExecutePayment(ctx, store, entity, quoteProto); err != nil {
+			return gsresponse.Auto[orchestratorv1.InitiatePaymentsResponse](h.logger, mservice.PaymentOrchestrator, err)
+		}
+
+		payments = append(payments, toProtoPayment(entity))
+	}
+
+	return gsresponse.Success(&orchestratorv1.InitiatePaymentsResponse{Payments: payments})
+}
+
 type initiatePaymentCommand struct {
 	engine paymentEngine
 	logger mlogger.Logger

api/payments/orchestrator/internal/service/orchestrator/helpers.go

@@ -145,7 +145,7 @@ func resolveTradeAmounts(intentAmount *moneyv1.Money, fxQuote *oraclev1.Quote, s
 	}
 }
 
-func computeAggregates(pay, settlement, fee *moneyv1.Money, network *chainv1.EstimateTransferFeeResponse, fxQuote *oraclev1.Quote) (*moneyv1.Money, *moneyv1.Money) {
+func computeAggregates(pay, settlement, fee *moneyv1.Money, network *chainv1.EstimateTransferFeeResponse, fxQuote *oraclev1.Quote, mode orchestratorv1.SettlementMode) (*moneyv1.Money, *moneyv1.Money) {
 	if pay == nil {
 		return nil, nil
 	}
@@ -166,7 +166,7 @@ func computeAggregates(pay, settlement, fee *moneyv1.Money, network *chainv1.Est
 		}
 	}
 
-	adjustDebit := func(m *moneyv1.Money) {
+	applyChargeToDebit := func(m *moneyv1.Money) {
 		converted, err := ensureCurrency(m, pay.GetCurrency(), fxQuote)
 		if err != nil || converted == nil {
 			return
@@ -176,7 +176,7 @@ func computeAggregates(pay, settlement, fee *moneyv1.Money, network *chainv1.Est
 		}
 	}
 
-	adjustSettlement := func(m *moneyv1.Money) {
+	applyChargeToSettlement := func(m *moneyv1.Money) {
 		converted, err := ensureCurrency(m, settlementCurrency, fxQuote)
 		if err != nil || converted == nil {
 			return
@@ -186,12 +186,22 @@ func computeAggregates(pay, settlement, fee *moneyv1.Money, network *chainv1.Est
 		}
 	}
 
-	adjustDebit(fee)
-	adjustSettlement(fee)
+	switch mode {
+	case orchestratorv1.SettlementMode_SETTLEMENT_MODE_FIX_RECEIVED:
+		// Sender pays the fee: keep settlement fixed, increase debit.
+		applyChargeToDebit(fee)
+	default:
+		// Recipient pays the fee (default): reduce settlement, keep debit fixed.
+		applyChargeToSettlement(fee)
+	}
 
 	if network != nil && network.GetNetworkFee() != nil {
-		adjustDebit(network.GetNetworkFee())
-		adjustSettlement(network.GetNetworkFee())
+		switch mode {
+		case orchestratorv1.SettlementMode_SETTLEMENT_MODE_FIX_RECEIVED:
+			applyChargeToDebit(network.GetNetworkFee())
+		default:
+			applyChargeToSettlement(network.GetNetworkFee())
+		}
 	}
 
 	return makeMoney(pay.GetCurrency(), debitDecimal), makeMoney(settlementCurrency, settlementDecimal)
@@ -204,20 +214,6 @@ func decimalFromMoney(m *moneyv1.Money) (decimal.Decimal, error) {
 	return decimal.NewFromString(m.GetAmount())
 }
 
-func decimalFromMoneyMatching(reference, candidate *moneyv1.Money) (*decimal.Decimal, error) {
-	if reference == nil || candidate == nil {
-		return nil, nil
-	}
-	if !strings.EqualFold(reference.GetCurrency(), candidate.GetCurrency()) {
-		return nil, nil
-	}
-	value, err := decimal.NewFromString(candidate.GetAmount())
-	if err != nil {
-		return nil, err
-	}
-	return &value, nil
-}
-
 func makeMoney(currency string, value decimal.Decimal) *moneyv1.Money {
 	return &moneyv1.Money{
 		Currency: currency,
@@ -383,6 +379,22 @@ func feeBreakdownFromQuote(quote *orchestratorv1.PaymentQuote) []*chainv1.Servic
 	return breakdown
 }
 
+func assignLedgerAccounts(lines []*feesv1.DerivedPostingLine, account string) []*feesv1.DerivedPostingLine {
+	if account == "" || len(lines) == 0 {
+		return lines
+	}
+	for _, line := range lines {
+		if line == nil {
+			continue
+		}
+		if strings.TrimSpace(line.GetLedgerAccountRef()) != "" {
+			continue
+		}
+		line.LedgerAccountRef = account
+	}
+	return lines
+}
+
 func moneyEquals(a, b *moneyv1.Money) bool {
 	if a == nil || b == nil {
 		return false

api/payments/orchestrator/internal/service/orchestrator/helpers_test.go

@@ -7,6 +7,7 @@ import (
 	moneyv1 "github.com/tech/sendico/pkg/proto/common/money/v1"
 	chainv1 "github.com/tech/sendico/pkg/proto/gateway/chain/v1"
 	oraclev1 "github.com/tech/sendico/pkg/proto/oracle/v1"
+	orchestratorv1 "github.com/tech/sendico/pkg/proto/payments/orchestrator/v1"
 )
 
 func TestResolveTradeAmountsBuyBase(t *testing.T) {
@@ -47,11 +48,32 @@ func TestComputeAggregatesConvertsCurrencies(t *testing.T) {
 		},
 	}
 
-	debit, settlement := computeAggregates(pay, settle, fee, network, fxQuote)
+	debit, settlement := computeAggregates(pay, settle, fee, network, fxQuote, orchestratorv1.SettlementMode_SETTLEMENT_MODE_FIX_RECEIVED)
 	if debit.GetCurrency() != "USD" || debit.GetAmount() != "115" {
 		t.Fatalf("expected debit 115 USD, got %s %s", debit.GetCurrency(), debit.GetAmount())
 	}
-	if settlement.GetCurrency() != "EUR" || settlement.GetAmount() != "42.5" {
-		t.Fatalf("expected settlement 42.5 EUR, got %s %s", settlement.GetCurrency(), settlement.GetAmount())
+	if settlement.GetCurrency() != "EUR" || settlement.GetAmount() != "50" {
+		t.Fatalf("expected settlement 50 EUR, got %s %s", settlement.GetCurrency(), settlement.GetAmount())
+	}
+}
+
+func TestComputeAggregatesRecipientPaysFee(t *testing.T) {
+	pay := &moneyv1.Money{Currency: "USDT", Amount: "100"}
+	settle := &moneyv1.Money{Currency: "RUB", Amount: "7932"} // 100 * 79.32
+	fee := &moneyv1.Money{Currency: "USDT", Amount: "7"}      // 7% of 100
+	fxQuote := &oraclev1.Quote{
+		Pair: &fxv1.CurrencyPair{Base: "USDT", Quote: "RUB"},
+		Side: fxv1.Side_SELL_BASE_BUY_QUOTE,
+		Price: &moneyv1.Decimal{
+			Value: "79.32",
+		},
+	}
+
+	debit, settlement := computeAggregates(pay, settle, fee, nil, fxQuote, orchestratorv1.SettlementMode_SETTLEMENT_MODE_FIX_SOURCE)
+	if debit.GetCurrency() != "USDT" || debit.GetAmount() != "100" {
+		t.Fatalf("expected debit 100 USDT, got %s %s", debit.GetCurrency(), debit.GetAmount())
+	}
+	if settlement.GetCurrency() != "RUB" || settlement.GetAmount() != "7376.76" {
+		t.Fatalf("expected settlement 7376.76 RUB, got %s %s", settlement.GetCurrency(), settlement.GetAmount())
 	}
 }

api/payments/orchestrator/internal/service/orchestrator/options.go

@@ -56,10 +56,11 @@ func (m mntxDependency) available() bool {
 	return m.client != nil
 }
 
-// CardGatewayRoute maps a gateway to its funding and fee destinations (addresses).
+// CardGatewayRoute maps a gateway to its funding and fee destinations.
 type CardGatewayRoute struct {
 	FundingAddress string
 	FeeAddress     string
+	FeeWalletRef   string
 }
 
 // WithFeeEngine wires the fee engine client.
@@ -113,6 +114,24 @@ func WithCardGatewayRoutes(routes map[string]CardGatewayRoute) Option {
 	}
 }
 
+// WithFeeLedgerAccounts maps gateway identifiers to ledger accounts used for fees.
+func WithFeeLedgerAccounts(routes map[string]string) Option {
+	return func(s *Service) {
+		if len(routes) == 0 {
+			return
+		}
+		s.deps.feeLedgerAccounts = make(map[string]string, len(routes))
+		for k, v := range routes {
+			key := strings.ToLower(strings.TrimSpace(k))
+			val := strings.TrimSpace(v)
+			if key == "" || val == "" {
+				continue
+			}
+			s.deps.feeLedgerAccounts[key] = val
+		}
+	}
+}
+
 // WithClock overrides the default clock.
 func WithClock(clock clockpkg.Clock) Option {
 	return func(s *Service) {

api/payments/orchestrator/internal/service/orchestrator/quote_batch.go

@@ -0,0 +1,145 @@
+package orchestrator
+
+import (
+	"fmt"
+	"sort"
+	"strings"
+	"time"
+
+	"github.com/shopspring/decimal"
+	"github.com/tech/sendico/payments/orchestrator/storage/model"
+	moneyv1 "github.com/tech/sendico/pkg/proto/common/money/v1"
+	orchestratorv1 "github.com/tech/sendico/pkg/proto/payments/orchestrator/v1"
+)
+
+func perIntentIdempotencyKey(base string, index int, total int) string {
+	base = strings.TrimSpace(base)
+	if base == "" {
+		return ""
+	}
+	if total <= 1 {
+		return base
+	}
+	return fmt.Sprintf("%s:%d", base, index+1)
+}
+
+func minQuoteExpiry(expires []time.Time) (time.Time, bool) {
+	var min time.Time
+	for _, exp := range expires {
+		if exp.IsZero() {
+			continue
+		}
+		if min.IsZero() || exp.Before(min) {
+			min = exp
+		}
+	}
+	if min.IsZero() {
+		return time.Time{}, false
+	}
+	return min, true
+}
+
+func aggregatePaymentQuotes(quotes []*orchestratorv1.PaymentQuote) (*orchestratorv1.PaymentQuoteAggregate, error) {
+	if len(quotes) == 0 {
+		return nil, nil
+	}
+	debitTotals := map[string]decimal.Decimal{}
+	settlementTotals := map[string]decimal.Decimal{}
+	feeTotals := map[string]decimal.Decimal{}
+	networkTotals := map[string]decimal.Decimal{}
+
+	for _, quote := range quotes {
+		if quote == nil {
+			continue
+		}
+		if err := accumulateMoney(debitTotals, quote.GetDebitAmount()); err != nil {
+			return nil, err
+		}
+		if err := accumulateMoney(settlementTotals, quote.GetExpectedSettlementAmount()); err != nil {
+			return nil, err
+		}
+		if err := accumulateMoney(feeTotals, quote.GetExpectedFeeTotal()); err != nil {
+			return nil, err
+		}
+		if nf := quote.GetNetworkFee(); nf != nil {
+			if err := accumulateMoney(networkTotals, nf.GetNetworkFee()); err != nil {
+				return nil, err
+			}
+		}
+	}
+
+	return &orchestratorv1.PaymentQuoteAggregate{
+		DebitAmounts:              totalsToMoney(debitTotals),
+		ExpectedSettlementAmounts: totalsToMoney(settlementTotals),
+		ExpectedFeeTotals:         totalsToMoney(feeTotals),
+		NetworkFeeTotals:          totalsToMoney(networkTotals),
+	}, nil
+}
+
+func accumulateMoney(totals map[string]decimal.Decimal, money *moneyv1.Money) error {
+	if money == nil {
+		return nil
+	}
+	currency := strings.TrimSpace(money.GetCurrency())
+	if currency == "" {
+		return nil
+	}
+	amount, err := decimal.NewFromString(money.GetAmount())
+	if err != nil {
+		return err
+	}
+	if current, ok := totals[currency]; ok {
+		totals[currency] = current.Add(amount)
+		return nil
+	}
+	totals[currency] = amount
+	return nil
+}
+
+func totalsToMoney(totals map[string]decimal.Decimal) []*moneyv1.Money {
+	if len(totals) == 0 {
+		return nil
+	}
+	currencies := make([]string, 0, len(totals))
+	for currency := range totals {
+		currencies = append(currencies, currency)
+	}
+	sort.Strings(currencies)
+
+	result := make([]*moneyv1.Money, 0, len(currencies))
+	for _, currency := range currencies {
+		amount := totals[currency]
+		result = append(result, &moneyv1.Money{
+			Amount:   amount.String(),
+			Currency: currency,
+		})
+	}
+	return result
+}
+
+func intentsFromProto(intents []*orchestratorv1.PaymentIntent) []model.PaymentIntent {
+	if len(intents) == 0 {
+		return nil
+	}
+	result := make([]model.PaymentIntent, 0, len(intents))
+	for _, intent := range intents {
+		result = append(result, intentFromProto(intent))
+	}
+	return result
+}
+
+func quoteSnapshotsFromProto(quotes []*orchestratorv1.PaymentQuote) []*model.PaymentQuoteSnapshot {
+	if len(quotes) == 0 {
+		return nil
+	}
+	result := make([]*model.PaymentQuoteSnapshot, 0, len(quotes))
+	for _, quote := range quotes {
+		if quote == nil {
+			continue
+		}
+		if snapshot := quoteSnapshotToModel(quote); snapshot != nil {
+			result = append(result, snapshot)
+		}
+	}
+	return result
+}

api/payments/orchestrator/internal/service/orchestrator/quote_batch_test.go

@@ -0,0 +1,102 @@
+package orchestrator
+
+import (
+	"testing"
+	"time"
+
+	"github.com/shopspring/decimal"
+	moneyv1 "github.com/tech/sendico/pkg/proto/common/money/v1"
+	chainv1 "github.com/tech/sendico/pkg/proto/gateway/chain/v1"
+	orchestratorv1 "github.com/tech/sendico/pkg/proto/payments/orchestrator/v1"
+)
+
+func TestAggregatePaymentQuotes(t *testing.T) {
+	quotes := []*orchestratorv1.PaymentQuote{
+		{
+			DebitAmount:              &moneyv1.Money{Amount: "10", Currency: "USD"},
+			ExpectedSettlementAmount: &moneyv1.Money{Amount: "8", Currency: "EUR"},
+			ExpectedFeeTotal:         &moneyv1.Money{Amount: "1", Currency: "USD"},
+			NetworkFee: &chainv1.EstimateTransferFeeResponse{
+				NetworkFee: &moneyv1.Money{Amount: "0.5", Currency: "USD"},
+			},
+		},
+		{
+			DebitAmount:              &moneyv1.Money{Amount: "5", Currency: "USD"},
+			ExpectedSettlementAmount: &moneyv1.Money{Amount: "1000", Currency: "NGN"},
+			ExpectedFeeTotal:         &moneyv1.Money{Amount: "2", Currency: "USD"},
+			NetworkFee: &chainv1.EstimateTransferFeeResponse{
+				NetworkFee: &moneyv1.Money{Amount: "100", Currency: "NGN"},
+			},
+		},
+	}
+
+	agg, err := aggregatePaymentQuotes(quotes)
+	if err != nil {
+		t.Fatalf("aggregatePaymentQuotes returned error: %v", err)
+	}
+
+	assertMoneyTotals(t, agg.GetDebitAmounts(), map[string]string{"USD": "15"})
+	assertMoneyTotals(t, agg.GetExpectedSettlementAmounts(), map[string]string{"EUR": "8", "NGN": "1000"})
+	assertMoneyTotals(t, agg.GetExpectedFeeTotals(), map[string]string{"USD": "3"})
+	assertMoneyTotals(t, agg.GetNetworkFeeTotals(), map[string]string{"USD": "0.5", "NGN": "100"})
+}
+
+func TestAggregatePaymentQuotesInvalidAmount(t *testing.T) {
+	quotes := []*orchestratorv1.PaymentQuote{
+		{
+			DebitAmount: &moneyv1.Money{Amount: "bad", Currency: "USD"},
+		},
+	}
+	if _, err := aggregatePaymentQuotes(quotes); err == nil {
+		t.Fatal("expected error for invalid amount")
+	}
+}
+
+func TestMinQuoteExpiry(t *testing.T) {
+	now := time.Now().UTC()
+	later := now.Add(10 * time.Minute)
+	earliest := now.Add(5 * time.Minute)
+
+	min, ok := minQuoteExpiry([]time.Time{later, {}, earliest})
+	if !ok {
+		t.Fatal("expected min expiry to be set")
+	}
+	if !min.Equal(earliest) {
+		t.Fatalf("expected min expiry %v, got %v", earliest, min)
+	}
+
+	if _, ok := minQuoteExpiry([]time.Time{{}}); ok {
+		t.Fatal("expected min expiry to be unset")
+	}
+}
+
+func assertMoneyTotals(t *testing.T, list []*moneyv1.Money, expected map[string]string) {
+	t.Helper()
+	got := make(map[string]decimal.Decimal, len(list))
+	for _, item := range list {
+		if item == nil {
+			continue
+		}
+		val, err := decimal.NewFromString(item.GetAmount())
+		if err != nil {
+			t.Fatalf("invalid money amount %q: %v", item.GetAmount(), err)
+		}
+		got[item.GetCurrency()] = val
+	}
+	if len(got) != len(expected) {
+		t.Fatalf("expected %d totals, got %d", len(expected), len(got))
+	}
+	for currency, amount := range expected {
+		val, err := decimal.NewFromString(amount)
+		if err != nil {
+			t.Fatalf("invalid expected amount %q: %v", amount, err)
+		}
+		gotVal, ok := got[currency]
+		if !ok {
+			t.Fatalf("missing currency %s", currency)
+		}
+		if !gotVal.Equal(val) {
+			t.Fatalf("expected %s %s, got %s", amount, currency, gotVal.String())
+		}
+	}
+}

api/payments/orchestrator/internal/service/orchestrator/quote_engine.go

@@ -52,7 +52,9 @@ func (s *Service) buildPaymentQuote(ctx context.Context, orgRef string, req *orc
 	} else if amount != nil {
 		feeCurrency = amount.GetCurrency()
 	}
-	feeTotal := extractFeeTotal(feeQuote.GetLines(), feeCurrency)
+	feeLines := cloneFeeLines(feeQuote.GetLines())
+	s.assignFeeLedgerAccounts(intent, feeLines)
+	feeTotal := extractFeeTotal(feeLines, feeCurrency)
 
 	var networkFee *chainv1.EstimateTransferFeeResponse
 	if shouldEstimateNetworkFee(intent) {
@@ -63,13 +65,13 @@ func (s *Service) buildPaymentQuote(ctx context.Context, orgRef string, req *orc
 		s.logger.Debug("network fee estimated", zap.String("org_ref", orgRef))
 	}
 
-	debitAmount, settlementAmount := computeAggregates(payAmount, settlementAmountBeforeFees, feeTotal, networkFee, fxQuote)
+	debitAmount, settlementAmount := computeAggregates(payAmount, settlementAmountBeforeFees, feeTotal, networkFee, fxQuote, intent.GetSettlementMode())
 
 	quote := &orchestratorv1.PaymentQuote{
 		DebitAmount:              debitAmount,
 		ExpectedSettlementAmount: settlementAmount,
 		ExpectedFeeTotal:         feeTotal,
-		FeeLines:                 cloneFeeLines(feeQuote.GetLines()),
+		FeeLines:                 feeLines,
 		FeeRules:                 cloneFeeRules(feeQuote.GetApplied()),
 		FxQuote:                  fxQuote,
 		NetworkFee:               networkFee,
@@ -207,3 +209,53 @@ func (s *Service) requestFXQuote(ctx context.Context, orgRef string, req *orches
 	}
 	return quoteToProto(quote), nil
 }
+
+func (s *Service) feeLedgerAccountForIntent(intent *orchestratorv1.PaymentIntent) string {
+	if intent == nil || len(s.deps.feeLedgerAccounts) == 0 {
+		return ""
+	}
+
+	key := s.gatewayKeyFromIntent(intent)
+	if key == "" {
+		return ""
+	}
+	return strings.TrimSpace(s.deps.feeLedgerAccounts[key])
+}
+
+func (s *Service) assignFeeLedgerAccounts(intent *orchestratorv1.PaymentIntent, lines []*feesv1.DerivedPostingLine) {
+	account := s.feeLedgerAccountForIntent(intent)
+	key := s.gatewayKeyFromIntent(intent)
+
+	missing := 0
+	for _, line := range lines {
+		if line == nil {
+			continue
+		}
+		if strings.TrimSpace(line.GetLedgerAccountRef()) == "" {
+			missing++
+		}
+	}
+	if missing == 0 {
+		return
+	}
+
+	if account == "" {
+		s.logger.Debug("no fee ledger account mapping found", zap.String("gateway", key), zap.Int("missing_lines", missing))
+		return
+	}
+	assignLedgerAccounts(lines, account)
+	s.logger.Debug("applied fee ledger account mapping", zap.String("gateway", key), zap.String("ledger_account", account), zap.Int("lines", missing))
+}
+
+func (s *Service) gatewayKeyFromIntent(intent *orchestratorv1.PaymentIntent) string {
+	if intent == nil {
+		return ""
+	}
+	key := strings.TrimSpace(intent.GetAttributes()["gateway"])
+	if key == "" {
+		if dest := intent.GetDestination(); dest != nil && dest.GetCard() != nil {
+			key = defaultCardGateway
+		}
+	}
+	return strings.ToLower(key)
+}

api/payments/orchestrator/internal/service/orchestrator/service.go

@@ -41,12 +41,13 @@ type Service struct {
 }
 
 type serviceDependencies struct {
-	fees       feesDependency
-	ledger     ledgerDependency
-	gateway    gatewayDependency
-	oracle     oracleDependency
-	mntx       mntxDependency
-	cardRoutes map[string]CardGatewayRoute
+	fees              feesDependency
+	ledger            ledgerDependency
+	gateway           gatewayDependency
+	oracle            oracleDependency
+	mntx              mntxDependency
+	cardRoutes        map[string]CardGatewayRoute
+	feeLedgerAccounts map[string]string
 }
 
 type handlerSet struct {
@@ -116,12 +117,24 @@ func (s *Service) QuotePayment(ctx context.Context, req *orchestratorv1.QuotePay
 	return executeUnary(ctx, s, "QuotePayment", s.h.commands.QuotePayment().Execute, req)
 }
 
+// QuotePayments aggregates downstream quotes for multiple intents.
+func (s *Service) QuotePayments(ctx context.Context, req *orchestratorv1.QuotePaymentsRequest) (*orchestratorv1.QuotePaymentsResponse, error) {
+	s.ensureHandlers()
+	return executeUnary(ctx, s, "QuotePayments", s.h.commands.QuotePayments().Execute, req)
+}
+
 // InitiatePayment captures a payment intent and reserves funds orchestration.
 func (s *Service) InitiatePayment(ctx context.Context, req *orchestratorv1.InitiatePaymentRequest) (*orchestratorv1.InitiatePaymentResponse, error) {
 	s.ensureHandlers()
 	return executeUnary(ctx, s, "InitiatePayment", s.h.commands.InitiatePayment().Execute, req)
 }
 
+// InitiatePayments executes multiple payments using a stored quote reference.
+func (s *Service) InitiatePayments(ctx context.Context, req *orchestratorv1.InitiatePaymentsRequest) (*orchestratorv1.InitiatePaymentsResponse, error) {
+	s.ensureHandlers()
+	return executeUnary(ctx, s, "InitiatePayments", s.h.commands.InitiatePayments().Execute, req)
+}
+
 // CancelPayment attempts to cancel an in-flight payment.
 func (s *Service) CancelPayment(ctx context.Context, req *orchestratorv1.CancelPaymentRequest) (*orchestratorv1.CancelPaymentResponse, error) {
 	s.ensureHandlers()

api/payments/orchestrator/internal/service/orchestrator/service_helpers_test.go

@@ -48,7 +48,8 @@ func TestRequireIdempotencyKey(t *testing.T) {
 func TestNewPayment(t *testing.T) {
 	org := primitive.NewObjectID()
 	intent := &orchestratorv1.PaymentIntent{
-		Amount: &moneyv1.Money{Currency: "USD", Amount: "10"},
+		Amount:         &moneyv1.Money{Currency: "USD", Amount: "10"},
+		SettlementMode: orchestratorv1.SettlementMode_SETTLEMENT_MODE_FIX_RECEIVED,
 	}
 	quote := &orchestratorv1.PaymentQuote{QuoteRef: "q1"}
 	p := newPayment(org, intent, "idem", map[string]string{"k": "v"}, quote)
@@ -58,6 +59,9 @@ func TestNewPayment(t *testing.T) {
 	if p.Intent.Amount == nil || p.Intent.Amount.GetAmount() != "10" {
 		t.Fatalf("intent not copied")
 	}
+	if p.Intent.SettlementMode != orchestratorv1.SettlementMode_SETTLEMENT_MODE_FIX_RECEIVED {
+		t.Fatalf("settlement mode not preserved")
+	}
 	if p.LastQuote == nil || p.LastQuote.QuoteRef != "q1" {
 		t.Fatalf("quote not copied")
 	}

api/payments/orchestrator/storage/model/payment.go

@@ -11,6 +11,7 @@ import (
 	moneyv1 "github.com/tech/sendico/pkg/proto/common/money/v1"
 	chainv1 "github.com/tech/sendico/pkg/proto/gateway/chain/v1"
 	oraclev1 "github.com/tech/sendico/pkg/proto/oracle/v1"
+	orchestratorv1 "github.com/tech/sendico/pkg/proto/payments/orchestrator/v1"
 )
 
 // PaymentKind captures the orchestrator intent type.
@@ -124,14 +125,15 @@ type FXIntent struct {
 
 // PaymentIntent models the requested payment operation.
 type PaymentIntent struct {
-	Kind        PaymentKind             `bson:"kind" json:"kind"`
-	Source      PaymentEndpoint         `bson:"source" json:"source"`
-	Destination PaymentEndpoint         `bson:"destination" json:"destination"`
-	Amount      *moneyv1.Money          `bson:"amount" json:"amount"`
-	RequiresFX  bool                    `bson:"requiresFx,omitempty" json:"requiresFx,omitempty"`
-	FX          *FXIntent               `bson:"fx,omitempty" json:"fx,omitempty"`
-	FeePolicy   *feesv1.PolicyOverrides `bson:"feePolicy,omitempty" json:"feePolicy,omitempty"`
-	Attributes  map[string]string       `bson:"attributes,omitempty" json:"attributes,omitempty"`
+	Kind           PaymentKind                   `bson:"kind" json:"kind"`
+	Source         PaymentEndpoint               `bson:"source" json:"source"`
+	Destination    PaymentEndpoint               `bson:"destination" json:"destination"`
+	Amount         *moneyv1.Money                `bson:"amount" json:"amount"`
+	RequiresFX     bool                          `bson:"requiresFx,omitempty" json:"requiresFx,omitempty"`
+	FX             *FXIntent                     `bson:"fx,omitempty" json:"fx,omitempty"`
+	FeePolicy      *feesv1.PolicyOverrides       `bson:"feePolicy,omitempty" json:"feePolicy,omitempty"`
+	SettlementMode orchestratorv1.SettlementMode `bson:"settlementMode,omitempty" json:"settlementMode,omitempty"`
+	Attributes     map[string]string             `bson:"attributes,omitempty" json:"attributes,omitempty"`
 }
 
 // PaymentQuoteSnapshot stores the latest quote info.
@@ -156,6 +158,24 @@ type ExecutionRefs struct {
 	FeeTransferRef   string `bson:"feeTransferRef,omitempty" json:"feeTransferRef,omitempty"`
 }
 
+// ExecutionStep describes a planned or executed payment step for reporting.
+type ExecutionStep struct {
+	Code            string            `bson:"code,omitempty" json:"code,omitempty"`
+	Description     string            `bson:"description,omitempty" json:"description,omitempty"`
+	Amount          *moneyv1.Money    `bson:"amount,omitempty" json:"amount,omitempty"`
+	NetworkFee      *moneyv1.Money    `bson:"networkFee,omitempty" json:"networkFee,omitempty"`
+	SourceWalletRef string            `bson:"sourceWalletRef,omitempty" json:"sourceWalletRef,omitempty"`
+	DestinationRef  string            `bson:"destinationRef,omitempty" json:"destinationRef,omitempty"`
+	TransferRef     string            `bson:"transferRef,omitempty" json:"transferRef,omitempty"`
+	Metadata        map[string]string `bson:"metadata,omitempty" json:"metadata,omitempty"`
+}
+
+// ExecutionPlan captures the ordered list of steps to execute a payment.
+type ExecutionPlan struct {
+	Steps            []*ExecutionStep `bson:"steps,omitempty" json:"steps,omitempty"`
+	TotalNetworkFee  *moneyv1.Money   `bson:"totalNetworkFee,omitempty" json:"totalNetworkFee,omitempty"`
+}
+
 // Payment persists orchestrated payment lifecycle.
 type Payment struct {
 	storable.Base               `bson:",inline" json:",inline"`
@@ -169,6 +189,7 @@ type Payment struct {
 	FailureReason  string                `bson:"failureReason,omitempty" json:"failureReason,omitempty"`
 	LastQuote      *PaymentQuoteSnapshot `bson:"lastQuote,omitempty" json:"lastQuote,omitempty"`
 	Execution      *ExecutionRefs        `bson:"execution,omitempty" json:"execution,omitempty"`
+	ExecutionPlan  *ExecutionPlan        `bson:"executionPlan,omitempty" json:"executionPlan,omitempty"`
 	Metadata       map[string]string     `bson:"metadata,omitempty" json:"metadata,omitempty"`
 	CardPayout     *CardPayout           `bson:"cardPayout,omitempty" json:"cardPayout,omitempty"`
 }
@@ -216,6 +237,23 @@ func (p *Payment) Normalize() {
 		p.Execution.FXEntryRef = strings.TrimSpace(p.Execution.FXEntryRef)
 		p.Execution.ChainTransferRef = strings.TrimSpace(p.Execution.ChainTransferRef)
 	}
+	if p.ExecutionPlan != nil {
+		for _, step := range p.ExecutionPlan.Steps {
+			if step == nil {
+				continue
+			}
+			step.Code = strings.TrimSpace(step.Code)
+			step.Description = strings.TrimSpace(step.Description)
+			step.SourceWalletRef = strings.TrimSpace(step.SourceWalletRef)
+			step.DestinationRef = strings.TrimSpace(step.DestinationRef)
+			step.TransferRef = strings.TrimSpace(step.TransferRef)
+			if step.Metadata != nil {
+				for k, v := range step.Metadata {
+					step.Metadata[k] = strings.TrimSpace(v)
+				}
+			}
+		}
+	}
 }
 
 func normalizeEndpoint(ep *PaymentEndpoint) {

api/payments/orchestrator/storage/model/quote.go

@@ -12,10 +12,12 @@ type PaymentQuoteRecord struct {
 	storable.Base               `bson:",inline" json:",inline"`
 	model.OrganizationBoundBase `bson:",inline" json:",inline"`
 
-	QuoteRef  string                `bson:"quoteRef" json:"quoteRef"`
-	Intent    PaymentIntent         `bson:"intent" json:"intent"`
-	Quote     *PaymentQuoteSnapshot `bson:"quote" json:"quote"`
-	ExpiresAt time.Time             `bson:"expiresAt" json:"expiresAt"`
+	QuoteRef  string                  `bson:"quoteRef" json:"quoteRef"`
+	Intent    PaymentIntent           `bson:"intent,omitempty" json:"intent,omitempty"`
+	Intents   []PaymentIntent         `bson:"intents,omitempty" json:"intents,omitempty"`
+	Quote     *PaymentQuoteSnapshot   `bson:"quote,omitempty" json:"quote,omitempty"`
+	Quotes    []*PaymentQuoteSnapshot `bson:"quotes,omitempty" json:"quotes,omitempty"`
+	ExpiresAt time.Time               `bson:"expiresAt" json:"expiresAt"`
 }
 
 // Collection implements storable.Storable.

api/payments/orchestrator/storage/mongo/store/quotes.go

@@ -73,6 +73,16 @@ func (q *Quotes) Create(ctx context.Context, quote *model.PaymentQuoteRecord) er
 			quote.Intent.Attributes[k] = strings.TrimSpace(v)
 		}
 	}
+	if len(quote.Intents) > 0 {
+		for i := range quote.Intents {
+			if quote.Intents[i].Attributes == nil {
+				continue
+			}
+			for k, v := range quote.Intents[i].Attributes {
+				quote.Intents[i].Attributes[k] = strings.TrimSpace(v)
+			}
+		}
+	}
 	quote.Update()
 
 	filter := repository.OrgFilter(quote.OrganizationRef).And(

api/pkg/api/routers/gsresponse/response.go

@@ -47,12 +47,7 @@ func Error[T any](logger mlogger.Logger, service mservice.Type, code codes.Code,
 		if err != nil {
 			fields = append(fields, zap.Error(err))
 		}
-		logFn := logger.Warn
-		switch code {
-		case codes.Internal, codes.DataLoss, codes.Unavailable:
-			logFn = logger.Error
-		}
-		logFn("gRPC request failed", fields...)
+		logger.Warn("gRPC request failed", fields...)
 
 		msg := message(err)
 		switch {

api/pkg/api/routers/gsresponse/response_test.go

@@ -6,9 +6,9 @@ import (
 	"fmt"
 	"testing"
 
+	"github.com/stretchr/testify/require"
 	"github.com/tech/sendico/pkg/merrors"
 	"github.com/tech/sendico/pkg/mservice"
-	"github.com/stretchr/testify/require"
 	"go.mongodb.org/mongo-driver/bson/primitive"
 	"go.uber.org/zap"
 	"google.golang.org/grpc/codes"
@@ -32,7 +32,7 @@ func TestUnarySuccess(t *testing.T) {
 		return Success(resp)
 	}
 
-	unary := Unary[testRequest, testResponse](logger, mservice.Type("test"), handler)
+	unary := Unary(logger, mservice.Type("test"), handler)
 	resp, err := unary(context.Background(), &testRequest{Value: "hello"})
 	require.NoError(t, err)
 	require.NotNil(t, resp)

api/pkg/db/internal/mongo/refreshtokensdb/db.go

@@ -37,7 +37,9 @@ func Create(logger mlogger.Logger, db *mongo.Database) (*RefreshTokenDB, error)
 			{Field: "clientId", Sort: ri.Asc},
 			{Field: "deviceId", Sort: ri.Asc},
 		},
-		Unique: true,
+		Unique:        true,
+		Name:          "unique_active_session",
+		PartialFilter: repository.Filter(IsRevokedField, false),
 	}); err != nil {
 		p.Logger.Error("Failed to create unique account/client/device index", zap.Error(err))
 		return nil, err

api/pkg/db/internal/mongo/refreshtokensdb/refreshtokensdb_test.go

@@ -10,23 +10,29 @@ import (
 	"testing"
 	"time"
 
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 	"github.com/tech/sendico/pkg/db/internal/mongo/refreshtokensdb"
 	"github.com/tech/sendico/pkg/db/repository"
 	"github.com/tech/sendico/pkg/db/repository/builder"
 	"github.com/tech/sendico/pkg/merrors"
 	factory "github.com/tech/sendico/pkg/mlogger/factory"
 	"github.com/tech/sendico/pkg/model"
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
 	"github.com/testcontainers/testcontainers-go"
 	"github.com/testcontainers/testcontainers-go/modules/mongodb"
 	"github.com/testcontainers/testcontainers-go/wait"
+	"go.mongodb.org/mongo-driver/bson"
 	"go.mongodb.org/mongo-driver/bson/primitive"
 	"go.mongodb.org/mongo-driver/mongo"
 	"go.mongodb.org/mongo-driver/mongo/options"
 )
 
 func setupTestDB(t *testing.T) (*refreshtokensdb.RefreshTokenDB, func()) {
+	db, _, cleanup := setupTestDBWithMongo(t)
+	return db, cleanup
+}
+
+func setupTestDBWithMongo(t *testing.T) (*refreshtokensdb.RefreshTokenDB, *mongo.Database, func()) {
 	// mark as helper for better test failure reporting
 	t.Helper()
 
@@ -62,7 +68,7 @@ func setupTestDB(t *testing.T) (*refreshtokensdb.RefreshTokenDB, func()) {
 		_ = mongoContainer.Terminate(termCtx)
 	}
 
-	return db, cleanup
+	return db, database, cleanup
 }
 
 func createTestRefreshToken(accountRef primitive.ObjectID, clientID, deviceID, token string) *model.RefreshToken {
@@ -332,6 +338,63 @@ func TestRefreshTokenDB_SessionReplacement(t *testing.T) {
 		_, err = db.GetByCRT(ctx, secondCRT)
 		require.NoError(t, err)
 	})
+
+	t.Run("Create_After_GlobalRevocation_AllowsNewActive", func(t *testing.T) {
+		userID := primitive.NewObjectID()
+		clientID := "web-app"
+		deviceID := "user-laptop"
+
+		firstToken := createTestRefreshToken(userID, clientID, deviceID, "revoked_token_123")
+		err := db.Create(ctx, firstToken)
+		require.NoError(t, err)
+		require.NotNil(t, firstToken.GetID())
+
+		// Global revoke (deviceID empty) — all tokens should be revoked
+		err = db.RevokeAll(ctx, userID, "")
+		require.NoError(t, err)
+
+		var revoked model.RefreshToken
+		err = db.Get(ctx, *firstToken.GetID(), &revoked)
+		require.NoError(t, err)
+		assert.True(t, revoked.IsRevoked)
+
+		// Creating a new token for the same account/client/device must succeed and produce an active token
+		reissueToken := createTestRefreshToken(userID, clientID, deviceID, "new_token_after_revocation")
+		err = db.Create(ctx, reissueToken)
+		require.NoError(t, err)
+
+		newCRT := &model.ClientRefreshToken{
+			SessionIdentifier: model.SessionIdentifier{
+				ClientID: clientID,
+				DeviceID: deviceID,
+			},
+			RefreshToken: "new_token_after_revocation",
+		}
+		_, err = db.GetByCRT(ctx, newCRT)
+		require.NoError(t, err)
+
+		// Old token must remain unusable
+		oldCRT := &model.ClientRefreshToken{
+			SessionIdentifier: model.SessionIdentifier{
+				ClientID: clientID,
+				DeviceID: deviceID,
+			},
+			RefreshToken: "revoked_token_123",
+		}
+		_, err = db.GetByCRT(ctx, oldCRT)
+		assert.Error(t, err)
+
+		// Both records exist: revoked + new active
+		query := repository.Query().
+			Filter(repository.AccountField(), userID).
+			And(
+				repository.Query().Comparison(repository.Field("clientId"), builder.Eq, clientID),
+				repository.Query().Comparison(repository.Field("deviceId"), builder.Eq, deviceID),
+			)
+		ids, err := db.Repository.ListIDs(ctx, query)
+		require.NoError(t, err)
+		assert.Len(t, ids, 2)
+	})
 }
 
 func TestRefreshTokenDB_ClientManagement(t *testing.T) {
@@ -637,3 +700,29 @@ func TestRefreshTokenDB_DatabaseIndexes(t *testing.T) {
 		assert.Len(t, ids, 5) // Should find 5 non-revoked tokens
 	})
 }
+
+func TestRefreshTokenDB_IndexPartialUniqueActiveSession(t *testing.T) {
+	db, database, cleanup := setupTestDBWithMongo(t)
+	defer cleanup()
+
+	ctx := context.Background()
+
+	cursor, err := database.Collection(db.Repository.Collection()).Indexes().List(ctx)
+	require.NoError(t, err)
+	defer cursor.Close(ctx)
+
+	found := false
+	for cursor.Next(ctx) {
+		var idx bson.M
+		require.NoError(t, cursor.Decode(&idx))
+		if idx["name"] == "unique_active_session" {
+			found = true
+			assert.Equal(t, true, idx["unique"])
+
+			partial, ok := idx["partialFilterExpression"].(bson.M)
+			require.True(t, ok)
+			assert.Equal(t, bson.M{"isRevoked": false}, partial)
+		}
+	}
+	assert.True(t, found, "unique_active_session index not found")
+}

api/pkg/db/internal/mongo/repositoryimp/index.go

@@ -41,6 +41,9 @@ func (r *MongoRepository) CreateIndex(def *ri.Definition) error {
 	if def.Name != "" {
 		opts.SetName(def.Name)
 	}
+	if def.PartialFilter != nil {
+		opts.SetPartialFilterExpression(def.PartialFilter.BuildQuery())
+	}
 
 	_, err := r.collection.Indexes().CreateOne(
 		context.Background(),

api/pkg/db/internal/mongo/repositoryimp/index_integration_test.go

@@ -0,0 +1,83 @@
+//go:build integration
+// +build integration
+
+package repositoryimp_test
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"github.com/tech/sendico/pkg/db/repository"
+	ri "github.com/tech/sendico/pkg/db/repository/index"
+	"github.com/testcontainers/testcontainers-go"
+	"github.com/testcontainers/testcontainers-go/modules/mongodb"
+	"github.com/testcontainers/testcontainers-go/wait"
+	"go.mongodb.org/mongo-driver/bson"
+	"go.mongodb.org/mongo-driver/mongo"
+	"go.mongodb.org/mongo-driver/mongo/options"
+)
+
+func TestCreateIndex_WithPartialFilter(t *testing.T) {
+	startCtx, startCancel := context.WithTimeout(context.Background(), 2*time.Minute)
+	defer startCancel()
+
+	mongoContainer, err := mongodb.Run(startCtx,
+		"mongo:latest",
+		mongodb.WithUsername("root"),
+		mongodb.WithPassword("password"),
+		testcontainers.WithWaitStrategy(wait.ForListeningPort("27017/tcp").WithStartupTimeout(2*time.Minute)),
+	)
+	require.NoError(t, err)
+
+	mongoURI, err := mongoContainer.ConnectionString(startCtx)
+	require.NoError(t, err)
+
+	client, err := mongo.Connect(startCtx, options.Client().ApplyURI(mongoURI))
+	require.NoError(t, err)
+	defer client.Disconnect(context.Background())
+
+	database := client.Database("test_partial_index_" + t.Name())
+	defer database.Drop(context.Background())
+
+	repo := repository.CreateMongoRepository(database, "partial_index_items")
+
+	def := &ri.Definition{
+		Keys: []ri.Key{
+			{Field: "field", Sort: ri.Asc},
+		},
+		Unique:        true,
+		Name:          "partial_unique_field_true",
+		PartialFilter: repository.Filter("flag", treu),
+	}
+
+	require.NoError(t, repo.CreateIndex(def))
+
+	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
+	defer cancel()
+
+	cursor, err := database.Collection(repo.Collection()).Indexes().List(ctx)
+	require.NoError(t, err)
+	defer cursor.Close(ctx)
+
+	found := false
+	for cursor.Next(ctx) {
+		var idx bson.M
+		require.NoError(t, cursor.Decode(&idx))
+		if idx["name"] == def.Name {
+			found = true
+			assert.Equal(t, true, idx["unique"])
+			assert.Equal(t, bson.M{"field": int32(1)}, idx["key"])
+			partial, ok := idx["partialFilterExpression"].(bson.M)
+			require.True(t, ok)
+			assert.Equal(t, bson.M{"flag": true}, partial)
+		}
+	}
+	assert.True(t, found, "partial unique index was not created")
+
+	termCtx, termCancel := context.WithTimeout(context.Background(), 30*time.Second)
+	defer termCancel()
+	_ = mongoContainer.Terminate(termCtx)
+}

api/pkg/db/repository/index/index.go

@@ -1,5 +1,7 @@
 package repository
 
+import "github.com/tech/sendico/pkg/db/repository/builder"
+
 type Sort int8
 
 const (
@@ -14,8 +16,9 @@ type Key struct {
 }
 
 type Definition struct {
-	Keys   []Key  // mandatory, at least one element
-	Unique bool   // unique constraint?
-	TTL    *int32 // seconds; nil means “no TTL”
-	Name   string // optional explicit name
+	Keys          []Key         // mandatory, at least one element
+	Unique        bool          // unique constraint?
+	TTL           *int32        // seconds; nil means “no TTL”
+	Name          string        // optional explicit name
+	PartialFilter builder.Query // optional: partialFilterExpression for conditional indexes
 }