api/gateway/mntx/README.md

@@ -20,12 +20,15 @@ This service now supports Monetix “payout by card”.
 Payload is built per Monetix spec:
 ```
 {
-  "general":  { "project_id": <int>, "payment_id": "<payout_id>", "signature": "<hmac>" },
+  "general":  { "project_id": <int>, "payment_id": "<operation_ref>", "signature": "<hmac>" },
   "customer": { id, first_name, last_name, middle_name?, ip_address, zip?, country?, state?, city?, address? },
   "payment":  { amount: <minor_units>, currency: "<ISO-4217>" },
   "card":     { pan, year?, month?, card_holder }
 }
 ```
+Gateway request contract additionally requires `parent_payment_ref` as a first-class field
+(separate from Monetix `payment_id`).
+
 Signature: HMAC-SHA256 over the JSON body (without `signature`), using `MONETIX_SECRET_KEY`.
 
 ## Callback handling

api/gateway/mntx/client/client.go

@@ -104,7 +104,7 @@ func (g *gatewayClient) CreateCardPayout(ctx context.Context, req *mntxv1.CardPa
 	if resp.GetReceipt() != nil && resp.GetReceipt().GetError() != nil {
 		return nil, connectorError(resp.GetReceipt().GetError())
 	}
-	return &mntxv1.CardPayoutResponse{Payout: payoutFromReceipt(req.GetPayoutId(), resp.GetReceipt())}, nil
+	return &mntxv1.CardPayoutResponse{Payout: payoutFromReceipt(req.GetPayoutId(), req.GetOperationRef(), req.GetParentPaymentRef(), resp.GetReceipt())}, nil
 }
 
 func (g *gatewayClient) CreateCardTokenPayout(ctx context.Context, req *mntxv1.CardTokenPayoutRequest) (*mntxv1.CardTokenPayoutResponse, error) {
@@ -121,7 +121,7 @@ func (g *gatewayClient) CreateCardTokenPayout(ctx context.Context, req *mntxv1.C
 	if resp.GetReceipt() != nil && resp.GetReceipt().GetError() != nil {
 		return nil, connectorError(resp.GetReceipt().GetError())
 	}
-	return &mntxv1.CardTokenPayoutResponse{Payout: payoutFromReceipt(req.GetPayoutId(), resp.GetReceipt())}, nil
+	return &mntxv1.CardTokenPayoutResponse{Payout: payoutFromReceipt(req.GetPayoutId(), req.GetOperationRef(), req.GetParentPaymentRef(), resp.GetReceipt())}, nil
 }
 
 func (g *gatewayClient) GetCardPayoutStatus(ctx context.Context, req *mntxv1.GetCardPayoutStatusRequest) (*mntxv1.GetCardPayoutStatusResponse, error) {
@@ -147,10 +147,12 @@ func operationFromCardPayout(req *mntxv1.CardPayoutRequest) (*connectorv1.Operat
 	}
 	params := payoutParamsFromCard(req)
 	money := moneyFromMinor(req.GetAmountMinor(), req.GetCurrency())
+	operationRef := fallbackNonEmpty(req.GetOperationRef(), req.GetPayoutId())
+	idempotencyKey := fallbackNonEmpty(req.GetIdempotencyKey(), operationRef)
 	op := &connectorv1.Operation{
 		Type:           connectorv1.OperationType_PAYOUT,
-		IdempotencyKey: strings.TrimSpace(req.GetIdempotencyKey()),
+		IdempotencyKey: idempotencyKey,
-		OperationRef:   strings.TrimSpace(req.GetOperationRef()),
+		OperationRef:   operationRef,
 		IntentRef:      strings.TrimSpace(req.GetIntentRef()),
 		Money:          money,
 		Params:         structFromMap(params),
@@ -165,9 +167,13 @@ func operationFromTokenPayout(req *mntxv1.CardTokenPayoutRequest) (*connectorv1.
 	}
 	params := payoutParamsFromToken(req)
 	money := moneyFromMinor(req.GetAmountMinor(), req.GetCurrency())
+	operationRef := fallbackNonEmpty(req.GetOperationRef(), req.GetPayoutId())
+	idempotencyKey := fallbackNonEmpty(req.GetIdempotencyKey(), operationRef)
 	op := &connectorv1.Operation{
 		Type:           connectorv1.OperationType_PAYOUT,
-		IdempotencyKey: strings.TrimSpace(req.GetPayoutId()),
+		IdempotencyKey: idempotencyKey,
+		OperationRef:   operationRef,
+		IntentRef:      strings.TrimSpace(req.GetIntentRef()),
 		Money:          money,
 		Params:         structFromMap(params),
 	}
@@ -192,9 +198,10 @@ func setOperationRolesFromMetadata(op *connectorv1.Operation, metadata map[strin
 }
 
 func payoutParamsFromCard(req *mntxv1.CardPayoutRequest) map[string]interface{} {
+	metadata := sanitizeMetadata(req.GetMetadata())
 	params := map[string]interface{}{
-		"payout_id":            strings.TrimSpace(req.GetPayoutId()),
 		"project_id":           req.GetProjectId(),
+		"parent_payment_ref":   strings.TrimSpace(req.GetParentPaymentRef()),
 		"customer_id":          strings.TrimSpace(req.GetCustomerId()),
 		"customer_first_name":  strings.TrimSpace(req.GetCustomerFirstName()),
 		"customer_middle_name": strings.TrimSpace(req.GetCustomerMiddleName()),
@@ -212,16 +219,17 @@ func payoutParamsFromCard(req *mntxv1.CardPayoutRequest) map[string]interface{}
 		"card_exp_month":       req.GetCardExpMonth(),
 		"card_holder":          strings.TrimSpace(req.GetCardHolder()),
 	}
-	if len(req.GetMetadata()) > 0 {
+	if len(metadata) > 0 {
-		params["metadata"] = mapStringToInterface(req.GetMetadata())
+		params["metadata"] = mapStringToInterface(metadata)
 	}
 	return params
 }
 
 func payoutParamsFromToken(req *mntxv1.CardTokenPayoutRequest) map[string]interface{} {
+	metadata := sanitizeMetadata(req.GetMetadata())
 	params := map[string]interface{}{
-		"payout_id":            strings.TrimSpace(req.GetPayoutId()),
 		"project_id":           req.GetProjectId(),
+		"parent_payment_ref":   strings.TrimSpace(req.GetParentPaymentRef()),
 		"customer_id":          strings.TrimSpace(req.GetCustomerId()),
 		"customer_first_name":  strings.TrimSpace(req.GetCustomerFirstName()),
 		"customer_middle_name": strings.TrimSpace(req.GetCustomerMiddleName()),
@@ -238,8 +246,8 @@ func payoutParamsFromToken(req *mntxv1.CardTokenPayoutRequest) map[string]interf
 		"card_holder":          strings.TrimSpace(req.GetCardHolder()),
 		"masked_pan":           strings.TrimSpace(req.GetMaskedPan()),
 	}
-	if len(req.GetMetadata()) > 0 {
+	if len(metadata) > 0 {
-		params["metadata"] = mapStringToInterface(req.GetMetadata())
+		params["metadata"] = mapStringToInterface(metadata)
 	}
 	return params
 }
@@ -255,16 +263,50 @@ func moneyFromMinor(amount int64, currency string) *moneyv1.Money {
 	}
 }
 
-func payoutFromReceipt(payoutID string, receipt *connectorv1.OperationReceipt) *mntxv1.CardPayoutState {
+func payoutFromReceipt(payoutID, operationRef, parentPaymentRef string, receipt *connectorv1.OperationReceipt) *mntxv1.CardPayoutState {
-	state := &mntxv1.CardPayoutState{PayoutId: strings.TrimSpace(payoutID)}
+	state := &mntxv1.CardPayoutState{
+		PayoutId:         fallbackNonEmpty(operationRef, payoutID),
+		ParentPaymentRef: strings.TrimSpace(parentPaymentRef),
+	}
 	if receipt == nil {
 		return state
 	}
+	if opID := strings.TrimSpace(receipt.GetOperationId()); opID != "" {
+		state.PayoutId = opID
+	}
 	state.Status = payoutStatusFromOperation(receipt.GetStatus())
 	state.ProviderPaymentId = strings.TrimSpace(receipt.GetProviderRef())
 	return state
 }
 
+func fallbackNonEmpty(values ...string) string {
+	for _, value := range values {
+		clean := strings.TrimSpace(value)
+		if clean != "" {
+			return clean
+		}
+	}
+	return ""
+}
+
+func sanitizeMetadata(source map[string]string) map[string]string {
+	if len(source) == 0 {
+		return nil
+	}
+	out := map[string]string{}
+	for key, value := range source {
+		k := strings.TrimSpace(key)
+		if k == "" {
+			continue
+		}
+		out[k] = strings.TrimSpace(value)
+	}
+	if len(out) == 0 {
+		return nil
+	}
+	return out
+}
+
 func payoutFromOperation(op *connectorv1.Operation) *mntxv1.CardPayoutState {
 	if op == nil {
 		return nil

api/gateway/mntx/internal/service/gateway/callback.go

@@ -110,6 +110,7 @@ func mapCallbackToState(clock clockpkg.Clock, cfg monetix.Config, cb monetixCall
 		ProviderCode:      cb.Operation.Code,
 		ProviderMessage:   cb.Operation.Message,
 		ProviderPaymentId: fallbackProviderPaymentID(cb),
+		OperationRef:      strings.TrimSpace(cb.Payment.ID),
 		UpdatedAt:         now,
 		CreatedAt:         now,
 	}

api/gateway/mntx/internal/service/gateway/card_payout_handlers.go

@@ -21,6 +21,8 @@ func (s *Service) handleCreateCardPayout(ctx context.Context, req *mntxv1.CardPa
 	log := s.logger.Named("card_payout")
 	log.Info("Create card payout request received",
 		zap.String("payout_id", strings.TrimSpace(req.GetPayoutId())),
+		zap.String("operation_ref", strings.TrimSpace(req.GetOperationRef())),
+		zap.String("parent_payment_ref", strings.TrimSpace(req.GetParentPaymentRef())),
 		zap.String("customer_id", strings.TrimSpace(req.GetCustomerId())),
 		zap.Int64("amount_minor", req.GetAmountMinor()),
 		zap.String("currency", strings.ToUpper(strings.TrimSpace(req.GetCurrency()))),
@@ -47,6 +49,8 @@ func (s *Service) handleCreateCardTokenPayout(ctx context.Context, req *mntxv1.C
 	log := s.logger.Named("card_token_payout")
 	log.Info("Create card token payout request received",
 		zap.String("payout_id", strings.TrimSpace(req.GetPayoutId())),
+		zap.String("operation_ref", strings.TrimSpace(req.GetOperationRef())),
+		zap.String("parent_payment_ref", strings.TrimSpace(req.GetParentPaymentRef())),
 		zap.String("customer_id", strings.TrimSpace(req.GetCustomerId())),
 		zap.Int64("amount_minor", req.GetAmountMinor()),
 		zap.String("currency", strings.ToUpper(strings.TrimSpace(req.GetCurrency()))),
@@ -120,6 +124,7 @@ func sanitizeCardPayoutRequest(req *mntxv1.CardPayoutRequest) *mntxv1.CardPayout
 		return req
 	}
 	r.PayoutId = strings.TrimSpace(r.GetPayoutId())
+	r.ParentPaymentRef = strings.TrimSpace(r.GetParentPaymentRef())
 	r.CustomerId = strings.TrimSpace(r.GetCustomerId())
 	r.CustomerFirstName = strings.TrimSpace(r.GetCustomerFirstName())
 	r.CustomerMiddleName = strings.TrimSpace(r.GetCustomerMiddleName())
@@ -133,6 +138,9 @@ func sanitizeCardPayoutRequest(req *mntxv1.CardPayoutRequest) *mntxv1.CardPayout
 	r.Currency = strings.ToUpper(strings.TrimSpace(r.GetCurrency()))
 	r.CardPan = strings.TrimSpace(r.GetCardPan())
 	r.CardHolder = strings.TrimSpace(r.GetCardHolder())
+	r.OperationRef = strings.TrimSpace(r.GetOperationRef())
+	r.IdempotencyKey = strings.TrimSpace(r.GetIdempotencyKey())
+	r.IntentRef = strings.TrimSpace(r.GetIntentRef())
 	return r
 }
 
@@ -146,6 +154,7 @@ func sanitizeCardTokenPayoutRequest(req *mntxv1.CardTokenPayoutRequest) *mntxv1.
 		return req
 	}
 	r.PayoutId = strings.TrimSpace(r.GetPayoutId())
+	r.ParentPaymentRef = strings.TrimSpace(r.GetParentPaymentRef())
 	r.CustomerId = strings.TrimSpace(r.GetCustomerId())
 	r.CustomerFirstName = strings.TrimSpace(r.GetCustomerFirstName())
 	r.CustomerMiddleName = strings.TrimSpace(r.GetCustomerMiddleName())
@@ -160,6 +169,9 @@ func sanitizeCardTokenPayoutRequest(req *mntxv1.CardTokenPayoutRequest) *mntxv1.
 	r.CardToken = strings.TrimSpace(r.GetCardToken())
 	r.CardHolder = strings.TrimSpace(r.GetCardHolder())
 	r.MaskedPan = strings.TrimSpace(r.GetMaskedPan())
+	r.OperationRef = strings.TrimSpace(r.GetOperationRef())
+	r.IdempotencyKey = strings.TrimSpace(r.GetIdempotencyKey())
+	r.IntentRef = strings.TrimSpace(r.GetIntentRef())
 	return r
 }
 
@@ -206,7 +218,7 @@ func buildCardPayoutRequest(projectID int64, req *mntxv1.CardPayoutRequest) mone
 	return monetix.CardPayoutRequest{
 		General: monetix.General{
 			ProjectID: projectID,
-			PaymentID: req.GetPayoutId(),
+			PaymentID: findOperationRef(req.GetOperationRef(), req.GetPayoutId()),
 		},
 		Customer: monetix.Customer{
 			ID:        req.GetCustomerId(),
@@ -232,7 +244,7 @@ func buildCardTokenPayoutRequest(projectID int64, req *mntxv1.CardTokenPayoutReq
 	return monetix.CardTokenPayoutRequest{
 		General: monetix.General{
 			ProjectID: projectID,
-			PaymentID: req.GetPayoutId(),
+			PaymentID: findOperationRef(req.GetOperationRef(), req.GetPayoutId()),
 		},
 		Customer: monetix.Customer{
 			ID:        req.GetCustomerId(),

api/gateway/mntx/internal/service/gateway/card_payout_store_test.go

@@ -27,6 +27,16 @@ type cardPayoutStore struct {
 	data map[string]*model.CardPayout
 }
 
+func payoutStoreKey(state *model.CardPayout) string {
+	if state == nil {
+		return ""
+	}
+	if ref := state.OperationRef; ref != "" {
+		return ref
+	}
+	return state.PaymentRef
+}
+
 func newCardPayoutStore() *cardPayoutStore {
 	return &cardPayoutStore{
 		data: make(map[string]*model.CardPayout),
@@ -42,26 +52,43 @@ func (s *cardPayoutStore) FindByIdempotencyKey(_ context.Context, key string) (*
 	return nil, nil
 }
 
-func (s *cardPayoutStore) FindByPaymentID(_ context.Context, id string) (*model.CardPayout, error) {
+func (s *cardPayoutStore) FindByOperationRef(_ context.Context, ref string) (*model.CardPayout, error) {
-	v, ok := s.data[id]
+	for _, v := range s.data {
-	if !ok {
+		if v.OperationRef == ref {
-		return nil, nil
-	}
 			return v, nil
+		}
+	}
+	return nil, nil
+}
+
+func (s *cardPayoutStore) FindByPaymentID(_ context.Context, id string) (*model.CardPayout, error) {
+	for _, v := range s.data {
+		if v.PaymentRef == id {
+			return v, nil
+		}
+	}
+	return nil, nil
 }
 
 func (s *cardPayoutStore) Upsert(_ context.Context, record *model.CardPayout) error {
-	s.data[record.PaymentRef] = record
+	s.data[payoutStoreKey(record)] = record
 	return nil
 }
 
 // Save is a helper for tests to pre-populate data.
 func (s *cardPayoutStore) Save(state *model.CardPayout) {
-	s.data[state.PaymentRef] = state
+	s.data[payoutStoreKey(state)] = state
 }
 
 // Get is a helper for tests to retrieve data.
 func (s *cardPayoutStore) Get(id string) (*model.CardPayout, bool) {
-	v, ok := s.data[id]
+	if v, ok := s.data[id]; ok {
-	return v, ok
+		return v, true
+	}
+	for _, v := range s.data {
+		if v.PaymentRef == id || v.OperationRef == id {
+			return v, true
+		}
+	}
+	return nil, false
 }

api/gateway/mntx/internal/service/gateway/card_payout_validation.go

@@ -14,8 +14,11 @@ func validateCardPayoutRequest(req *mntxv1.CardPayoutRequest, cfg monetix.Config
 		return newPayoutError("invalid_request", merrors.InvalidArgument("request cannot be empty"))
 	}
 
-	if strings.TrimSpace(req.GetPayoutId()) == "" {
+	if err := validateOperationIdentity(strings.TrimSpace(req.GetPayoutId()), strings.TrimSpace(req.GetOperationRef())); err != nil {
-		return newPayoutError("missing_payout_id", merrors.InvalidArgument("payout_id is required", "payout_id"))
+		return err
+	}
+	if strings.TrimSpace(req.GetParentPaymentRef()) == "" {
+		return newPayoutError("missing_parent_payment_ref", merrors.InvalidArgument("parent_payment_ref is required", "parent_payment_ref"))
 	}
 	if strings.TrimSpace(req.GetCustomerId()) == "" {
 		return newPayoutError("missing_customer_id", merrors.InvalidArgument("customer_id is required", "customer_id"))
@@ -81,3 +84,16 @@ func validateCardExpiryFields(month uint32, year uint32) error {
 	}
 	return nil
 }
+
+func validateOperationIdentity(payoutID, operationRef string) error {
+	payoutID = strings.TrimSpace(payoutID)
+	operationRef = strings.TrimSpace(operationRef)
+	switch {
+	case payoutID == "" && operationRef == "":
+		return newPayoutError("missing_operation_ref", merrors.InvalidArgument("operation_ref or payout_id is required", "operation_ref"))
+	case payoutID != "" && operationRef != "":
+		return newPayoutError("ambiguous_operation_ref", merrors.InvalidArgument("provide either operation_ref or payout_id, not both"))
+	default:
+		return nil
+	}
+}

api/gateway/mntx/internal/service/gateway/card_payout_validation_test.go

@@ -24,9 +24,22 @@ func TestValidateCardPayoutRequest_Errors(t *testing.T) {
 		expected string
 	}{
 		{
-			name:     "missing_payout_id",
+			name:     "missing_operation_identity",
 			mutate:   func(r *mntxv1.CardPayoutRequest) { r.PayoutId = "" },
-			expected: "missing_payout_id",
+			expected: "missing_operation_ref",
+		},
+		{
+			name:     "missing_parent_payment_ref",
+			mutate:   func(r *mntxv1.CardPayoutRequest) { r.ParentPaymentRef = "" },
+			expected: "missing_parent_payment_ref",
+		},
+		{
+			name: "both_operation_and_payout_identity",
+			mutate: func(r *mntxv1.CardPayoutRequest) {
+				r.PayoutId = "parent-1"
+				r.OperationRef = "parent-1:hop_1_card_payout_send"
+			},
+			expected: "ambiguous_operation_ref",
 		},
 		{
 			name:     "missing_customer_id",

api/gateway/mntx/internal/service/gateway/card_processor.go

@@ -57,13 +57,44 @@ func mergePayoutStateWithExisting(state, existing *model.CardPayout) {
 	if state.IntentRef == "" {
 		state.IntentRef = existing.IntentRef
 	}
+	if existing.PaymentRef != "" {
+		state.PaymentRef = existing.PaymentRef
+	}
+}
+
+func findOperationRef(operationRef, payoutID string) string {
+	ref := strings.TrimSpace(operationRef)
+	if ref != "" {
+		return ref
+	}
+	return strings.TrimSpace(payoutID)
+}
+
+func (p *cardPayoutProcessor) findExistingPayoutState(ctx context.Context, state *model.CardPayout) (*model.CardPayout, error) {
+	if p == nil || state == nil {
+		return nil, nil
+	}
+	if opRef := strings.TrimSpace(state.OperationRef); opRef != "" {
+		existing, err := p.store.Payouts().FindByOperationRef(ctx, opRef)
+		if err == nil {
+			if existing != nil {
+				return existing, nil
+			}
+		}
+		if !errors.Is(err, merrors.ErrNoData) {
+			if err != nil {
+				return nil, err
+			}
+		}
+	}
+	return nil, nil
 }
 
 func (p *cardPayoutProcessor) findAndMergePayoutState(ctx context.Context, state *model.CardPayout) (*model.CardPayout, error) {
 	if p == nil || state == nil {
 		return nil, nil
 	}
-	existing, err := p.store.Payouts().FindByPaymentID(ctx, state.PaymentRef)
+	existing, err := p.findExistingPayoutState(ctx, state)
 	if err != nil {
 		return nil, err
 	}
@@ -218,13 +249,15 @@ func (p *cardPayoutProcessor) Submit(ctx context.Context, req *mntxv1.CardPayout
 	}
 
 	req = sanitizeCardPayoutRequest(req)
+	operationRef := findOperationRef(req.GetOperationRef(), req.GetPayoutId())
+	parentPaymentRef := strings.TrimSpace(req.GetParentPaymentRef())
 
 	p.logger.Info("Submitting card payout",
-		zap.String("payout_id", strings.TrimSpace(req.GetPayoutId())),
+		zap.String("parent_payment_ref", parentPaymentRef),
 		zap.String("customer_id", strings.TrimSpace(req.GetCustomerId())),
 		zap.Int64("amount_minor", req.GetAmountMinor()),
 		zap.String("currency", strings.ToUpper(strings.TrimSpace(req.GetCurrency()))),
-		zap.String("operation_ref", strings.TrimSpace(req.GetOperationRef())),
+		zap.String("operation_ref", operationRef),
 		zap.String("idempotency_key", strings.TrimSpace(req.GetIdempotencyKey())),
 	)
 
@@ -235,7 +268,8 @@ func (p *cardPayoutProcessor) Submit(ctx context.Context, req *mntxv1.CardPayout
 
 	if err := validateCardPayoutRequest(req, p.config); err != nil {
 		p.logger.Warn("Card payout validation failed",
-			zap.String("payout_id", req.GetPayoutId()),
+			zap.String("parent_payment_ref", parentPaymentRef),
+			zap.String("operation_ref", operationRef),
 			zap.String("customer_id", req.GetCustomerId()),
 			zap.Error(err),
 		)
@@ -243,7 +277,8 @@ func (p *cardPayoutProcessor) Submit(ctx context.Context, req *mntxv1.CardPayout
 	}
 	if err := p.validatePerTxMinimum(req.GetAmountMinor(), req.GetCurrency()); err != nil {
 		p.logger.Warn("Card payout amount below configured minimum",
-			zap.String("payout_id", req.GetPayoutId()),
+			zap.String("parent_payment_ref", parentPaymentRef),
+			zap.String("operation_ref", operationRef),
 			zap.String("customer_id", req.GetCustomerId()),
 			zap.Int64("amount_minor", req.GetAmountMinor()),
 			zap.String("currency", strings.ToUpper(strings.TrimSpace(req.GetCurrency()))),
@@ -253,7 +288,7 @@ func (p *cardPayoutProcessor) Submit(ctx context.Context, req *mntxv1.CardPayout
 		return nil, err
 	}
 
-	projectID, err := p.resolveProjectID(req.GetProjectId(), "payout_id", req.GetPayoutId())
+	projectID, err := p.resolveProjectID(req.GetProjectId(), "operation_ref", operationRef)
 	if err != nil {
 		return nil, err
 	}
@@ -264,8 +299,8 @@ func (p *cardPayoutProcessor) Submit(ctx context.Context, req *mntxv1.CardPayout
 		Base: storable.Base{
 			ID: bson.NilObjectID,
 		},
-		PaymentRef:     strings.TrimSpace(req.GetPayoutId()),
+		PaymentRef:     parentPaymentRef,
-		OperationRef:   strings.TrimSpace(req.GetOperationRef()),
+		OperationRef:   operationRef,
 		IdempotencyKey: strings.TrimSpace(req.GetIdempotencyKey()),
 		IntentRef:      strings.TrimSpace(req.GetIntentRef()),
 		ProjectID:      projectID,
@@ -339,13 +374,15 @@ func (p *cardPayoutProcessor) SubmitToken(ctx context.Context, req *mntxv1.CardT
 	}
 
 	req = sanitizeCardTokenPayoutRequest(req)
+	operationRef := findOperationRef(req.GetOperationRef(), req.GetPayoutId())
+	parentPaymentRef := strings.TrimSpace(req.GetParentPaymentRef())
 
 	p.logger.Info("Submitting card token payout",
-		zap.String("payout_id", strings.TrimSpace(req.GetPayoutId())),
+		zap.String("parent_payment_ref", parentPaymentRef),
 		zap.String("customer_id", strings.TrimSpace(req.GetCustomerId())),
 		zap.Int64("amount_minor", req.GetAmountMinor()),
 		zap.String("currency", strings.ToUpper(strings.TrimSpace(req.GetCurrency()))),
-		zap.String("operation_ref", strings.TrimSpace(req.GetOperationRef())),
+		zap.String("operation_ref", operationRef),
 		zap.String("idempotency_key", strings.TrimSpace(req.GetIdempotencyKey())),
 	)
 
@@ -356,7 +393,8 @@ func (p *cardPayoutProcessor) SubmitToken(ctx context.Context, req *mntxv1.CardT
 
 	if err := validateCardTokenPayoutRequest(req, p.config); err != nil {
 		p.logger.Warn("Card token payout validation failed",
-			zap.String("payout_id", req.GetPayoutId()),
+			zap.String("parent_payment_ref", parentPaymentRef),
+			zap.String("operation_ref", operationRef),
 			zap.String("customer_id", req.GetCustomerId()),
 			zap.Error(err),
 		)
@@ -364,7 +402,8 @@ func (p *cardPayoutProcessor) SubmitToken(ctx context.Context, req *mntxv1.CardT
 	}
 	if err := p.validatePerTxMinimum(req.GetAmountMinor(), req.GetCurrency()); err != nil {
 		p.logger.Warn("Card token payout amount below configured minimum",
-			zap.String("payout_id", req.GetPayoutId()),
+			zap.String("parent_payment_ref", parentPaymentRef),
+			zap.String("operation_ref", operationRef),
 			zap.String("customer_id", req.GetCustomerId()),
 			zap.Int64("amount_minor", req.GetAmountMinor()),
 			zap.String("currency", strings.ToUpper(strings.TrimSpace(req.GetCurrency()))),
@@ -374,16 +413,17 @@ func (p *cardPayoutProcessor) SubmitToken(ctx context.Context, req *mntxv1.CardT
 		return nil, err
 	}
 
-	projectID, err := p.resolveProjectID(req.GetProjectId(), "payout_id", req.GetPayoutId())
+	projectID, err := p.resolveProjectID(req.GetProjectId(), "operation_ref", operationRef)
 	if err != nil {
 		return nil, err
 	}
 
 	now := p.clock.Now()
 	state := &model.CardPayout{
-		PaymentRef:     strings.TrimSpace(req.GetPayoutId()),
+		PaymentRef:     parentPaymentRef,
-		OperationRef:   strings.TrimSpace(req.GetOperationRef()),
+		OperationRef:   operationRef,
 		IdempotencyKey: strings.TrimSpace(req.GetIdempotencyKey()),
+		IntentRef:      strings.TrimSpace(req.GetIntentRef()),
 		ProjectID:      projectID,
 		CustomerID:     strings.TrimSpace(req.GetCustomerId()),
 		AmountMinor:    req.GetAmountMinor(),
@@ -509,21 +549,26 @@ func (p *cardPayoutProcessor) Status(ctx context.Context, payoutID string) (*mnt
 	}
 
 	id := strings.TrimSpace(payoutID)
-	p.logger.Info("Card payout status requested", zap.String("payout_id", id))
+	p.logger.Info("Card payout status requested", zap.String("operation_ref", id))
 
 	if id == "" {
 		p.logger.Warn("Payout status requested with empty payout_id")
 		return nil, merrors.InvalidArgument("payout_id is required", "payout_id")
 	}
 
-	state, err := p.store.Payouts().FindByPaymentID(ctx, id)
+	state, err := p.store.Payouts().FindByOperationRef(ctx, id)
-	if err != nil || state == nil {
+	if err != nil && !errors.Is(err, merrors.ErrNoData) {
-		p.logger.Warn("Payout status not found", zap.String("payout_id", id), zap.Error(err))
+		p.logger.Warn("Payout status lookup by operation ref failed", zap.String("operation_ref", id), zap.Error(err))
+		return nil, err
+	}
+	if state == nil || errors.Is(err, merrors.ErrNoData) {
+		p.logger.Warn("Payout status not found", zap.String("operation_ref", id))
 		return nil, merrors.NoData("payout not found")
 	}
 
 	p.logger.Info("Card payout status resolved",
 		zap.String("payment_ref", state.PaymentRef),
+		zap.String("operation_ref", state.OperationRef),
 		zap.String("status", string(state.Status)),
 	)
 

api/gateway/mntx/internal/service/gateway/card_processor_test.go

@@ -5,6 +5,7 @@ import (
 	"context"
 	"encoding/json"
 	"errors"
+	"fmt"
 	"io"
 	"net/http"
 	"testing"
@@ -45,7 +46,8 @@ func TestCardPayoutProcessor_Submit_Success(t *testing.T) {
 
 	repo := newMockRepository()
 	repo.payouts.Save(&model.CardPayout{
-		PaymentRef: "payout-1",
+		PaymentRef:   "payment-parent-1",
+		OperationRef: "payout-1",
 		CreatedAt:    existingCreated,
 	})
 
@@ -227,3 +229,173 @@ func TestCardPayoutProcessor_ProcessCallback(t *testing.T) {
 		t.Fatalf("expected success status in model, got %v", state.Status)
 	}
 }
+
+func TestCardPayoutProcessor_Submit_SameParentDifferentOperationsStoredSeparately(t *testing.T) {
+	cfg := monetix.Config{
+		BaseURL:           "https://monetix.test",
+		SecretKey:         "secret",
+		ProjectID:         99,
+		AllowedCurrencies: []string{"RUB"},
+	}
+
+	repo := newMockRepository()
+	var callN int
+	httpClient := &http.Client{
+		Transport: roundTripperFunc(func(r *http.Request) (*http.Response, error) {
+			callN++
+			resp := monetix.APIResponse{}
+			resp.Operation.RequestID = fmt.Sprintf("req-%d", callN)
+			body, _ := json.Marshal(resp)
+			return &http.Response{
+				StatusCode: http.StatusOK,
+				Body:       io.NopCloser(bytes.NewReader(body)),
+				Header:     http.Header{"Content-Type": []string{"application/json"}},
+			}, nil
+		}),
+	}
+	processor := newCardPayoutProcessor(
+		zap.NewNop(),
+		cfg,
+		staticClock{now: time.Date(2026, 3, 4, 1, 2, 3, 0, time.UTC)},
+		repo,
+		httpClient,
+		nil,
+	)
+
+	parentPaymentRef := "payment-parent-1"
+	op1 := parentPaymentRef + ":hop_4_card_payout_send"
+	op2 := parentPaymentRef + ":hop_4_card_payout_send_2"
+
+	req1 := validCardPayoutRequest()
+	req1.PayoutId = ""
+	req1.OperationRef = op1
+	req1.IdempotencyKey = "idem-1"
+	req1.ParentPaymentRef = parentPaymentRef
+	req1.CardPan = "2204310000002456"
+
+	req2 := validCardPayoutRequest()
+	req2.PayoutId = ""
+	req2.OperationRef = op2
+	req2.IdempotencyKey = "idem-2"
+	req2.ParentPaymentRef = parentPaymentRef
+	req2.CardPan = "2204320000009754"
+
+	if _, err := processor.Submit(context.Background(), req1); err != nil {
+		t.Fatalf("first submit failed: %v", err)
+	}
+	if _, err := processor.Submit(context.Background(), req2); err != nil {
+		t.Fatalf("second submit failed: %v", err)
+	}
+
+	first, err := repo.payouts.FindByOperationRef(context.Background(), op1)
+	if err != nil || first == nil {
+		t.Fatalf("expected first operation stored, err=%v", err)
+	}
+	second, err := repo.payouts.FindByOperationRef(context.Background(), op2)
+	if err != nil || second == nil {
+		t.Fatalf("expected second operation stored, err=%v", err)
+	}
+
+	if got, want := first.PaymentRef, parentPaymentRef; got != want {
+		t.Fatalf("first parent payment ref mismatch: got=%q want=%q", got, want)
+	}
+	if got, want := second.PaymentRef, parentPaymentRef; got != want {
+		t.Fatalf("second parent payment ref mismatch: got=%q want=%q", got, want)
+	}
+	if got, want := first.OperationRef, op1; got != want {
+		t.Fatalf("first operation ref mismatch: got=%q want=%q", got, want)
+	}
+	if got, want := second.OperationRef, op2; got != want {
+		t.Fatalf("second operation ref mismatch: got=%q want=%q", got, want)
+	}
+	if first.ProviderPaymentID == "" || second.ProviderPaymentID == "" {
+		t.Fatalf("expected provider payment ids for both operations")
+	}
+	if first.ProviderPaymentID == second.ProviderPaymentID {
+		t.Fatalf("expected different provider payment ids, got=%q", first.ProviderPaymentID)
+	}
+}
+
+func TestCardPayoutProcessor_ProcessCallback_UpdatesMatchingOperationWithinSameParent(t *testing.T) {
+	cfg := monetix.Config{
+		SecretKey:         "secret",
+		StatusSuccess:     "success",
+		StatusProcessing:  "processing",
+		AllowedCurrencies: []string{"RUB"},
+	}
+
+	parentPaymentRef := "payment-parent-1"
+	op1 := parentPaymentRef + ":hop_4_card_payout_send"
+	op2 := parentPaymentRef + ":hop_4_card_payout_send_2"
+	now := time.Date(2026, 3, 4, 2, 3, 4, 0, time.UTC)
+
+	repo := newMockRepository()
+	repo.payouts.Save(&model.CardPayout{
+		PaymentRef:   parentPaymentRef,
+		OperationRef: op1,
+		Status:       model.PayoutStatusWaiting,
+		CreatedAt:    now.Add(-time.Minute),
+		UpdatedAt:    now.Add(-time.Minute),
+	})
+	repo.payouts.Save(&model.CardPayout{
+		PaymentRef:   parentPaymentRef,
+		OperationRef: op2,
+		Status:       model.PayoutStatusWaiting,
+		CreatedAt:    now.Add(-time.Minute),
+		UpdatedAt:    now.Add(-time.Minute),
+	})
+
+	processor := newCardPayoutProcessor(
+		zap.NewNop(),
+		cfg,
+		staticClock{now: now},
+		repo,
+		&http.Client{},
+		nil,
+	)
+
+	cb := baseCallback()
+	cb.Payment.ID = op2
+	cb.Payment.Status = "success"
+	cb.Operation.Status = "success"
+	cb.Operation.Code = "0"
+	cb.Operation.Provider.PaymentID = "provider-op-2"
+	cb.Payment.Sum.Currency = "RUB"
+
+	sig, err := monetix.SignPayload(cb, cfg.SecretKey)
+	if err != nil {
+		t.Fatalf("failed to sign callback: %v", err)
+	}
+	cb.Signature = sig
+	payload, err := json.Marshal(cb)
+	if err != nil {
+		t.Fatalf("failed to marshal callback: %v", err)
+	}
+
+	status, err := processor.ProcessCallback(context.Background(), payload)
+	if err != nil {
+		t.Fatalf("expected no error, got %v", err)
+	}
+	if status != http.StatusOK {
+		t.Fatalf("expected status ok, got %d", status)
+	}
+
+	first, err := repo.payouts.FindByOperationRef(context.Background(), op1)
+	if err != nil || first == nil {
+		t.Fatalf("expected first operation present, err=%v", err)
+	}
+	second, err := repo.payouts.FindByOperationRef(context.Background(), op2)
+	if err != nil || second == nil {
+		t.Fatalf("expected second operation present, err=%v", err)
+	}
+
+	if got, want := first.Status, model.PayoutStatusWaiting; got != want {
+		t.Fatalf("first operation status mismatch: got=%v want=%v", got, want)
+	}
+	if got, want := second.Status, model.PayoutStatusSuccess; got != want {
+		t.Fatalf("second operation status mismatch: got=%v want=%v", got, want)
+	}
+	if got, want := second.PaymentRef, parentPaymentRef; got != want {
+		t.Fatalf("second parent payment ref mismatch: got=%q want=%q", got, want)
+	}
+}

api/gateway/mntx/internal/service/gateway/card_token_validation.go

@@ -13,8 +13,11 @@ func validateCardTokenPayoutRequest(req *mntxv1.CardTokenPayoutRequest, cfg mone
 		return newPayoutError("invalid_request", merrors.InvalidArgument("request cannot be empty"))
 	}
 
-	if strings.TrimSpace(req.GetPayoutId()) == "" {
+	if err := validateOperationIdentity(strings.TrimSpace(req.GetPayoutId()), strings.TrimSpace(req.GetOperationRef())); err != nil {
-		return newPayoutError("missing_payout_id", merrors.InvalidArgument("payout_id is required", "payout_id"))
+		return err
+	}
+	if strings.TrimSpace(req.GetParentPaymentRef()) == "" {
+		return newPayoutError("missing_parent_payment_ref", merrors.InvalidArgument("parent_payment_ref is required", "parent_payment_ref"))
 	}
 	if strings.TrimSpace(req.GetCustomerId()) == "" {
 		return newPayoutError("missing_customer_id", merrors.InvalidArgument("customer_id is required", "customer_id"))

api/gateway/mntx/internal/service/gateway/card_token_validation_test.go

@@ -24,9 +24,22 @@ func TestValidateCardTokenPayoutRequest_Errors(t *testing.T) {
 		expected string
 	}{
 		{
-			name:     "missing_payout_id",
+			name:     "missing_operation_identity",
 			mutate:   func(r *mntxv1.CardTokenPayoutRequest) { r.PayoutId = "" },
-			expected: "missing_payout_id",
+			expected: "missing_operation_ref",
+		},
+		{
+			name:     "missing_parent_payment_ref",
+			mutate:   func(r *mntxv1.CardTokenPayoutRequest) { r.ParentPaymentRef = "" },
+			expected: "missing_parent_payment_ref",
+		},
+		{
+			name: "both_operation_and_payout_identity",
+			mutate: func(r *mntxv1.CardTokenPayoutRequest) {
+				r.PayoutId = "parent-1"
+				r.OperationRef = "parent-1:hop_1_card_payout_send"
+			},
+			expected: "ambiguous_operation_ref",
 		},
 		{
 			name:     "missing_customer_id",

api/gateway/mntx/internal/service/gateway/connector.go

@@ -69,20 +69,18 @@ func (s *Service) SubmitOperation(ctx context.Context, req *connectorv1.SubmitOp
 	if err != nil {
 		return &connectorv1.SubmitOperationResponse{Receipt: &connectorv1.OperationReceipt{Error: connectorError(connectorv1.ErrorCode_INVALID_PARAMS, err.Error(), op, "")}}, nil
 	}
+	parentPaymentRef := strings.TrimSpace(reader.String("parent_payment_ref"))
 
-	payoutID := strings.TrimSpace(reader.String("payout_id"))
+	payoutID := operationIDForRequest(operationRef)
-	if payoutID == "" {
-		payoutID = strings.TrimSpace(op.GetIdempotencyKey())
-	}
 
 	if strings.TrimSpace(reader.String("card_token")) != "" {
-		resp, err := s.CreateCardTokenPayout(ctx, buildCardTokenPayoutRequestFromParams(reader, payoutID, amountMinor, currency))
+		resp, err := s.CreateCardTokenPayout(ctx, buildCardTokenPayoutRequestFromParams(reader, payoutID, parentPaymentRef, idempotencyKey, operationRef, intentRef, amountMinor, currency))
 		if err != nil {
 			return &connectorv1.SubmitOperationResponse{Receipt: &connectorv1.OperationReceipt{Error: connectorError(mapErrorCode(err), err.Error(), op, "")}}, nil
 		}
 		return &connectorv1.SubmitOperationResponse{Receipt: payoutReceipt(resp.GetPayout())}, nil
 	}
-	cr := buildCardPayoutRequestFromParams(reader, payoutID, idempotencyKey, operationRef, intentRef, amountMinor, currency)
+	cr := buildCardPayoutRequestFromParams(reader, payoutID, parentPaymentRef, idempotencyKey, operationRef, intentRef, amountMinor, currency)
 	resp, err := s.CreateCardPayout(ctx, cr)
 	if err != nil {
 		return &connectorv1.SubmitOperationResponse{Receipt: &connectorv1.OperationReceipt{Error: connectorError(mapErrorCode(err), err.Error(), op, "")}}, nil
@@ -119,6 +117,7 @@ func mntxOperationParams() []*connectorv1.OperationParamSpec {
 			{Key: "card_holder", Type: connectorv1.ParamType_STRING, Required: false},
 			{Key: "amount_minor", Type: connectorv1.ParamType_INT, Required: false},
 			{Key: "project_id", Type: connectorv1.ParamType_INT, Required: false},
+			{Key: "parent_payment_ref", Type: connectorv1.ParamType_STRING, Required: true},
 			{Key: "customer_middle_name", Type: connectorv1.ParamType_STRING, Required: false},
 			{Key: "customer_country", Type: connectorv1.ParamType_STRING, Required: false},
 			{Key: "customer_state", Type: connectorv1.ParamType_STRING, Required: false},
@@ -169,9 +168,29 @@ func currencyFromOperation(op *connectorv1.Operation) string {
 	return strings.ToUpper(currency)
 }
 
-func buildCardTokenPayoutRequestFromParams(reader params.Reader, payoutID string, amountMinor int64, currency string) *mntxv1.CardTokenPayoutRequest {
+func operationIDForRequest(operationRef string) string {
+	return strings.TrimSpace(operationRef)
+}
+
+func metadataFromReader(reader params.Reader) map[string]string {
+	metadata := reader.StringMap("metadata")
+	if len(metadata) == 0 {
+		return nil
+	}
+	return metadata
+}
+
+func buildCardTokenPayoutRequestFromParams(reader params.Reader,
+	payoutID, parentPaymentRef, idempotencyKey, operationRef, intentRef string,
+	amountMinor int64, currency string) *mntxv1.CardTokenPayoutRequest {
+	operationRef = strings.TrimSpace(operationRef)
+	payoutID = strings.TrimSpace(payoutID)
+	if operationRef != "" {
+		payoutID = ""
+	}
 	req := &mntxv1.CardTokenPayoutRequest{
 		PayoutId:           payoutID,
+		ParentPaymentRef:   strings.TrimSpace(parentPaymentRef),
 		ProjectId:          readerInt64(reader, "project_id"),
 		CustomerId:         strings.TrimSpace(reader.String("customer_id")),
 		CustomerFirstName:  strings.TrimSpace(reader.String("customer_first_name")),
@@ -188,16 +207,25 @@ func buildCardTokenPayoutRequestFromParams(reader params.Reader, payoutID string
 		CardToken:          strings.TrimSpace(reader.String("card_token")),
 		CardHolder:         strings.TrimSpace(reader.String("card_holder")),
 		MaskedPan:          strings.TrimSpace(reader.String("masked_pan")),
-		Metadata:           reader.StringMap("metadata"),
+		Metadata:           metadataFromReader(reader),
+		OperationRef:       operationRef,
+		IdempotencyKey:     strings.TrimSpace(idempotencyKey),
+		IntentRef:          strings.TrimSpace(intentRef),
 	}
 	return req
 }
 
 func buildCardPayoutRequestFromParams(reader params.Reader,
-	payoutID, idempotencyKey, operationRef, intentRef string,
+	payoutID, parentPaymentRef, idempotencyKey, operationRef, intentRef string,
 	amountMinor int64, currency string) *mntxv1.CardPayoutRequest {
+	operationRef = strings.TrimSpace(operationRef)
+	payoutID = strings.TrimSpace(payoutID)
+	if operationRef != "" {
+		payoutID = ""
+	}
 	return &mntxv1.CardPayoutRequest{
 		PayoutId:           payoutID,
+		ParentPaymentRef:   strings.TrimSpace(parentPaymentRef),
 		ProjectId:          readerInt64(reader, "project_id"),
 		CustomerId:         strings.TrimSpace(reader.String("customer_id")),
 		CustomerFirstName:  strings.TrimSpace(reader.String("customer_first_name")),
@@ -215,10 +243,10 @@ func buildCardPayoutRequestFromParams(reader params.Reader,
 		CardExpYear:        uint32(readerInt64(reader, "card_exp_year")),
 		CardExpMonth:       uint32(readerInt64(reader, "card_exp_month")),
 		CardHolder:         strings.TrimSpace(reader.String("card_holder")),
-		Metadata:           reader.StringMap("metadata"),
+		Metadata:           metadataFromReader(reader),
 		OperationRef:       operationRef,
-		IdempotencyKey:     idempotencyKey,
+		IdempotencyKey:     strings.TrimSpace(idempotencyKey),
-		IntentRef:          intentRef,
+		IntentRef:          strings.TrimSpace(intentRef),
 	}
 }
 
@@ -236,7 +264,7 @@ func payoutReceipt(state *mntxv1.CardPayoutState) *connectorv1.OperationReceipt
 		}
 	}
 	return &connectorv1.OperationReceipt{
-		OperationId: strings.TrimSpace(state.GetPayoutId()),
+		OperationId: firstNonEmpty(strings.TrimSpace(state.GetOperationRef()), strings.TrimSpace(state.GetPayoutId())),
 		Status:      payoutStatusToOperation(state.GetStatus()),
 		ProviderRef: strings.TrimSpace(state.GetProviderPaymentId()),
 	}
@@ -247,7 +275,7 @@ func payoutToOperation(state *mntxv1.CardPayoutState) *connectorv1.Operation {
 		return nil
 	}
 	return &connectorv1.Operation{
-		OperationId: strings.TrimSpace(state.GetPayoutId()),
+		OperationId: firstNonEmpty(strings.TrimSpace(state.GetOperationRef()), strings.TrimSpace(state.GetPayoutId())),
 		Type:        connectorv1.OperationType_PAYOUT,
 		Status:      payoutStatusToOperation(state.GetStatus()),
 		Money: &moneyv1.Money{

api/gateway/mntx/internal/service/gateway/helpers.go

@@ -1,6 +1,7 @@
 package gateway
 
 import (
+	"strings"
 	"time"
 
 	"github.com/tech/sendico/gateway/mntx/storage/model"
@@ -22,7 +23,7 @@ func CardPayoutStateFromProto(clock clockpkg.Clock, p *mntxv1.CardPayoutState) *
 	}
 
 	return &model.CardPayout{
-		PaymentRef:        p.PayoutId,
+		PaymentRef:        strings.TrimSpace(p.GetParentPaymentRef()),
 		OperationRef:      p.GetOperationRef(),
 		IntentRef:         p.GetIntentRef(),
 		IdempotencyKey:    p.GetIdempotencyKey(),
@@ -41,7 +42,8 @@ func CardPayoutStateFromProto(clock clockpkg.Clock, p *mntxv1.CardPayoutState) *
 
 func StateToProto(m *model.CardPayout) *mntxv1.CardPayoutState {
 	return &mntxv1.CardPayoutState{
-		PayoutId:          m.PaymentRef,
+		PayoutId:          firstNonEmpty(m.OperationRef, m.PaymentRef),
+		ParentPaymentRef:  m.PaymentRef,
 		ProjectId:         m.ProjectID,
 		CustomerId:        m.CustomerID,
 		AmountMinor:       m.AmountMinor,

api/gateway/mntx/internal/service/gateway/testhelpers_test.go

@@ -36,6 +36,7 @@ func testMonetixConfig() monetix.Config {
 func validCardPayoutRequest() *mntxv1.CardPayoutRequest {
 	return &mntxv1.CardPayoutRequest{
 		PayoutId:          "payout-1",
+		ParentPaymentRef:  "payment-parent-1",
 		CustomerId:        "cust-1",
 		CustomerFirstName: "Jane",
 		CustomerLastName:  "Doe",
@@ -52,6 +53,7 @@ func validCardPayoutRequest() *mntxv1.CardPayoutRequest {
 func validCardTokenPayoutRequest() *mntxv1.CardTokenPayoutRequest {
 	return &mntxv1.CardTokenPayoutRequest{
 		PayoutId:          "payout-1",
+		ParentPaymentRef:  "payment-parent-1",
 		CustomerId:        "cust-1",
 		CustomerFirstName: "Jane",
 		CustomerLastName:  "Doe",

api/gateway/mntx/storage/mongo/store/payouts.go

@@ -19,6 +19,7 @@ const (
 	payoutsCollection = "card_payouts"
 	payoutIdemField   = "idempotencyKey"
 	payoutIdField     = "paymentRef"
+	payoutOpField     = "operationRef"
 )
 
 type Payouts struct {
@@ -36,6 +37,16 @@ func NewPayouts(logger mlogger.Logger, db *mongo.Database) (*Payouts, error) {
 	logger = logger.Named("payouts").With(zap.String("collection", payoutsCollection))
 
 	repo := repository.CreateMongoRepository(db, payoutsCollection)
+	if err := repo.CreateIndex(&ri.Definition{
+		Keys:   []ri.Key{{Field: payoutOpField, Sort: ri.Asc}},
+		Unique: true,
+		Sparse: true,
+	}); err != nil {
+		logger.Error("Failed to create payouts operation index",
+			zap.Error(err),
+			zap.String("index_field", payoutOpField))
+		return nil, err
+	}
 	if err := repo.CreateIndex(&ri.Definition{
 		Keys:   []ri.Key{{Field: payoutIdemField, Sort: ri.Asc}},
 		Unique: true,
@@ -63,6 +74,10 @@ func (p *Payouts) FindByIdempotencyKey(ctx context.Context, key string) (*model.
 	return p.findOneByField(ctx, payoutIdemField, key)
 }
 
+func (p *Payouts) FindByOperationRef(ctx context.Context, operationRef string) (*model.CardPayout, error) {
+	return p.findOneByField(ctx, payoutOpField, operationRef)
+}
+
 func (p *Payouts) FindByPaymentID(ctx context.Context, paymentID string) (*model.CardPayout, error) {
 	return p.findOneByField(ctx, payoutIdField, paymentID)
 }

api/gateway/mntx/storage/storage.go

@@ -15,6 +15,7 @@ type Repository interface {
 
 type PayoutsStore interface {
 	FindByIdempotencyKey(ctx context.Context, key string) (*model.CardPayout, error)
+	FindByOperationRef(ctx context.Context, key string) (*model.CardPayout, error)
 	FindByPaymentID(ctx context.Context, key string) (*model.CardPayout, error)
 	Upsert(ctx context.Context, record *model.CardPayout) error
 }

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

@@ -74,7 +74,6 @@ func (e *gatewayCardPayoutExecutor) ExecuteCardPayout(ctx context.Context, req s
 
 	stepToken := cardPayoutStepToken(req.Step)
 	operationRef := cardPayoutOperationRef(req.Payment, stepToken)
-	payoutRef := cardPayoutRef(req.Payment)
 	idempotencyKey := cardPayoutIdempotencyKey(req.Payment, stepToken)
 	projectID := cardPayoutProjectID(req.Payment)
 	customer := cardPayoutCustomerFromPayment(req.Payment, card, req.Step.Metadata)
@@ -85,8 +84,8 @@ func (e *gatewayCardPayoutExecutor) ExecuteCardPayout(ctx context.Context, req s
 	var responsePayout *mntxv1.CardPayoutState
 	if token := strings.TrimSpace(card.Token); token != "" {
 		resp, createErr := client.CreateCardTokenPayout(ctx, &mntxv1.CardTokenPayoutRequest{
-			PayoutId:           payoutRef,
 			ProjectId:          projectID,
+			ParentPaymentRef:   strings.TrimSpace(req.Payment.PaymentRef),
 			CustomerId:         customer.id,
 			CustomerFirstName:  customer.firstName,
 			CustomerMiddleName: customer.middleName,
@@ -123,8 +122,8 @@ func (e *gatewayCardPayoutExecutor) ExecuteCardPayout(ctx context.Context, req s
 			return nil, merrors.InvalidArgument("card payout send: card expiry is required")
 		}
 		resp, createErr := client.CreateCardPayout(ctx, &mntxv1.CardPayoutRequest{
-			PayoutId:           payoutRef,
 			ProjectId:          projectID,
+			ParentPaymentRef:   strings.TrimSpace(req.Payment.PaymentRef),
 			CustomerId:         customer.id,
 			CustomerFirstName:  customer.firstName,
 			CustomerMiddleName: customer.middleName,
@@ -155,8 +154,8 @@ func (e *gatewayCardPayoutExecutor) ExecuteCardPayout(ctx context.Context, req s
 		responsePayout = resp.GetPayout()
 	}
 
-	resolvedPayoutRef := firstNonEmpty(strings.TrimSpace(responsePayout.GetPayoutId()), payoutRef)
 	resolvedOperationRef := firstNonEmpty(strings.TrimSpace(responsePayout.GetOperationRef()), operationRef)
+	resolvedPayoutRef := firstNonEmpty(strings.TrimSpace(responsePayout.GetPayoutId()), resolvedOperationRef)
 	gatewayInstanceID := firstNonEmpty(
 		strings.TrimSpace(req.Step.InstanceID),
 		strings.TrimSpace(gateway.InstanceID),
@@ -356,14 +355,6 @@ func cardPayoutOperationRef(payment *agg.Payment, stepToken string) string {
 	return joinRef(base, stepToken)
 }
 
-func cardPayoutRef(payment *agg.Payment) string {
-	base := ""
-	if payment != nil {
-		base = firstNonEmpty(strings.TrimSpace(payment.PaymentRef), strings.TrimSpace(payment.IdempotencyKey), "card_payout")
-	}
-	return base
-}
-
 func cardPayoutIdempotencyKey(payment *agg.Payment, stepToken string) string {
 	base := ""
 	if payment != nil {

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

@@ -122,7 +122,7 @@ func TestGatewayCardPayoutExecutor_ExecuteCardPayout_SubmitsCardPayout(t *testin
 	if got, want := dialAddress, "mntx-gateway:50051"; got != want {
 		t.Fatalf("dial address mismatch: got=%q want=%q", got, want)
 	}
-	if got, want := payoutReq.GetPayoutId(), "payment-1"; got != want {
+	if got, want := payoutReq.GetPayoutId(), ""; got != want {
 		t.Fatalf("payout_id mismatch: got=%q want=%q", got, want)
 	}
 	if got, want := payoutReq.GetOperationRef(), "payment-1:hop_4_card_payout_send"; got != want {
@@ -143,6 +143,9 @@ func TestGatewayCardPayoutExecutor_ExecuteCardPayout_SubmitsCardPayout(t *testin
 	if got, want := payoutReq.GetMetadata()[settlementMetadataOutgoingLeg], string(discovery.RailCardPayout); got != want {
 		t.Fatalf("outgoing_leg metadata mismatch: got=%q want=%q", got, want)
 	}
+	if got, want := payoutReq.GetParentPaymentRef(), "payment-1"; got != want {
+		t.Fatalf("parent_payment_ref mismatch: got=%q want=%q", got, want)
+	}
 	if len(out.StepExecution.ExternalRefs) != 3 {
 		t.Fatalf("expected 3 external refs, got=%d", len(out.StepExecution.ExternalRefs))
 	}
@@ -263,12 +266,18 @@ func TestGatewayCardPayoutExecutor_ExecuteCardPayout_UsesStepMetadataOverrides(t
 	if got, want := payoutReq.GetCurrency(), "RUB"; got != want {
 		t.Fatalf("currency mismatch: got=%q want=%q", got, want)
 	}
+	if got, want := payoutReq.GetPayoutId(), ""; got != want {
+		t.Fatalf("payout_id mismatch: got=%q want=%q", got, want)
+	}
 	if got, want := payoutReq.GetCardPan(), "2200700142860162"; got != want {
 		t.Fatalf("card pan mismatch: got=%q want=%q", got, want)
 	}
 	if got, want := payoutReq.GetMetadata()[batchmeta.MetaPayoutTargetRef], "recipient-2"; got != want {
 		t.Fatalf("target_ref metadata mismatch: got=%q want=%q", got, want)
 	}
+	if got, want := payoutReq.GetParentPaymentRef(), "payment-2"; got != want {
+		t.Fatalf("parent_payment_ref mismatch: got=%q want=%q", got, want)
+	}
 }
 
 func TestGatewayCardPayoutExecutor_ExecuteCardPayout_RequiresGatewayRegistry(t *testing.T) {
@@ -310,3 +319,140 @@ func TestGatewayCardPayoutExecutor_ExecuteCardPayout_RequiresGatewayRegistry(t *
 		t.Fatalf("unexpected error: %v", err)
 	}
 }
+
+func TestGatewayCardPayoutExecutor_ExecuteCardPayout_BatchChildrenUseDistinctOperationRefsAndSharedParent(t *testing.T) {
+	orgID := bson.NewObjectID()
+
+	var payoutReqs []*mntxv1.CardPayoutRequest
+	executor := &gatewayCardPayoutExecutor{
+		gatewayRegistry: &fakeGatewayRegistry{
+			items: []*model.GatewayInstanceDescriptor{
+				{
+					ID:         paymenttypes.DefaultCardsGatewayID,
+					InstanceID: paymenttypes.DefaultCardsGatewayID,
+					Rail:       discovery.RailCardPayout,
+					InvokeURI:  "grpc://mntx-gateway:50051",
+					IsEnabled:  true,
+				},
+			},
+		},
+		dialClient: func(_ context.Context, _ string) (mntxclient.Client, error) {
+			return &mntxclient.Fake{
+				CreateCardPayoutFn: func(_ context.Context, req *mntxv1.CardPayoutRequest) (*mntxv1.CardPayoutResponse, error) {
+					payoutReqs = append(payoutReqs, req)
+					return &mntxv1.CardPayoutResponse{
+						Payout: &mntxv1.CardPayoutState{
+							PayoutId:     req.GetOperationRef(),
+							OperationRef: req.GetOperationRef(),
+						},
+					}, nil
+				},
+			}, nil
+		},
+	}
+
+	payment := &agg.Payment{
+		OrganizationBoundBase: pm.OrganizationBoundBase{OrganizationRef: orgID},
+		PaymentRef:            "payment-3",
+		IdempotencyKey:        "idem-3",
+		QuotationRef:          "quote-3",
+		IntentSnapshot: model.PaymentIntent{
+			Ref: "intent-3",
+			Destination: model.PaymentEndpoint{
+				Type: model.EndpointTypeCard,
+				Card: &model.CardEndpoint{
+					Pan:      "2200700142860161",
+					ExpMonth: 3,
+					ExpYear:  2030,
+				},
+			},
+			Customer: &model.Customer{
+				ID:        "cust-3",
+				FirstName: "Stephan",
+				LastName:  "Deshevikh",
+				IP:        "198.51.100.10",
+			},
+			Amount: &paymenttypes.Money{
+				Amount:   "1.000000",
+				Currency: "USDT",
+			},
+		},
+		QuoteSnapshot: &model.PaymentQuoteSnapshot{
+			ExpectedSettlementAmount: &paymenttypes.Money{
+				Amount:   "76.50",
+				Currency: "RUB",
+			},
+			QuoteRef: "quote-3",
+		},
+	}
+
+	firstReq := sexec.StepRequest{
+		Payment: payment,
+		Step: xplan.Step{
+			StepRef:    "hop_4_card_payout_send",
+			StepCode:   "hop.4.card_payout.send",
+			Action:     discovery.RailOperationSend,
+			Rail:       discovery.RailCardPayout,
+			Gateway:    paymenttypes.DefaultCardsGatewayID,
+			InstanceID: paymenttypes.DefaultCardsGatewayID,
+		},
+		StepExecution: agg.StepExecution{
+			StepRef:  "hop_4_card_payout_send",
+			StepCode: "hop.4.card_payout.send",
+			Attempt:  1,
+		},
+	}
+	secondReq := sexec.StepRequest{
+		Payment: payment,
+		Step: xplan.Step{
+			StepRef:    "hop_4_card_payout_send_2",
+			StepCode:   "hop.4.card_payout.send",
+			Action:     discovery.RailOperationSend,
+			Rail:       discovery.RailCardPayout,
+			Gateway:    paymenttypes.DefaultCardsGatewayID,
+			InstanceID: paymenttypes.DefaultCardsGatewayID,
+			Metadata: map[string]string{
+				batchmeta.MetaPayoutTargetRef: "recipient-2",
+				batchmeta.MetaAmount:          "150",
+				batchmeta.MetaCurrency:        "RUB",
+				batchmeta.MetaCardPan:         "2200700142860162",
+				batchmeta.MetaCardExpMonth:    "4",
+				batchmeta.MetaCardExpYear:     "2030",
+			},
+		},
+		StepExecution: agg.StepExecution{
+			StepRef:  "hop_4_card_payout_send_2",
+			StepCode: "hop.4.card_payout.send",
+			Attempt:  1,
+		},
+	}
+
+	if _, err := executor.ExecuteCardPayout(context.Background(), firstReq); err != nil {
+		t.Fatalf("first ExecuteCardPayout returned error: %v", err)
+	}
+	if _, err := executor.ExecuteCardPayout(context.Background(), secondReq); err != nil {
+		t.Fatalf("second ExecuteCardPayout returned error: %v", err)
+	}
+
+	if got, want := len(payoutReqs), 2; got != want {
+		t.Fatalf("submitted request count mismatch: got=%d want=%d", got, want)
+	}
+	if got, want := payoutReqs[0].GetOperationRef(), "payment-3:hop_4_card_payout_send"; got != want {
+		t.Fatalf("first operation_ref mismatch: got=%q want=%q", got, want)
+	}
+	if got, want := payoutReqs[1].GetOperationRef(), "payment-3:hop_4_card_payout_send_2"; got != want {
+		t.Fatalf("second operation_ref mismatch: got=%q want=%q", got, want)
+	}
+	if payoutReqs[0].GetPayoutId() != "" || payoutReqs[1].GetPayoutId() != "" {
+		t.Fatalf("expected empty payout_id for both child operations")
+	}
+	if got, want := payoutReqs[0].GetParentPaymentRef(), "payment-3"; got != want {
+		t.Fatalf("first parent_payment_ref mismatch: got=%q want=%q", got, want)
+	}
+	if got, want := payoutReqs[1].GetParentPaymentRef(), "payment-3"; got != want {
+		t.Fatalf("second parent_payment_ref mismatch: got=%q want=%q", got, want)
+	}
+	if payoutReqs[0].GetCardPan() == payoutReqs[1].GetCardPan() {
+		t.Fatalf("expected different destination cards across child operations")
+	}
+}

api/proto/gateway/mntx/v1/mntx.proto

@@ -21,7 +21,7 @@ enum PayoutStatus {
 
 // Request to initiate a Monetix card payout.
 message CardPayoutRequest {
-  string payout_id = 1; // internal payout id, mapped to Monetix payment_id
+  string payout_id = 1; // alternate operation id mapped to Monetix payment_id
   int64 project_id = 2; // optional override; defaults to configured project id
   string customer_id = 3;
   string customer_first_name = 4;
@@ -40,9 +40,10 @@ message CardPayoutRequest {
   uint32 card_exp_month = 17;
   string card_holder = 18;
   map<string, string> metadata = 30;
-  string operation_ref = 31;
+  string operation_ref = 31; // preferred operation id mapped to Monetix payment_id
   string idempotency_key = 32;
   string intent_ref = 33;
+  string parent_payment_ref = 34;
 }
 
 // Persisted payout state for retrieval and status updates.
@@ -61,6 +62,7 @@ message CardPayoutState {
   string operation_ref = 12;
   string idempotency_key = 13;
   string intent_ref = 14;
+  string parent_payment_ref = 15;
 }
 
 // Response returned immediately after submitting a payout to Monetix.
@@ -97,7 +99,7 @@ message ListGatewayInstancesResponse {
 
 // Request to initiate a token-based card payout.
 message CardTokenPayoutRequest {
-  string payout_id = 1;
+  string payout_id = 1; // alternate operation id
   int64 project_id = 2;
   string customer_id = 3;
 
@@ -119,9 +121,10 @@ message CardTokenPayoutRequest {
   string card_holder = 16;
   string masked_pan = 17;
   map<string, string> metadata = 30;
-  string operation_ref = 31;
+  string operation_ref = 31; // preferred operation id
   string idempotency_key = 32;
   string intent_ref = 33;
+  string parent_payment_ref = 34;
 }
 
 // Response returned immediately after submitting a token payout to Monetix.

frontend/pshared/lib/provider/payment/quotation/intent_builder.dart

@@ -24,6 +24,7 @@ import 'package:pshared/provider/payment/flow.dart';
 import 'package:pshared/provider/recipient/provider.dart';
 import 'package:pshared/utils/payment/fx_helpers.dart';
 
+
 class QuotationIntentBuilder {
   static const String _settlementCurrency = 'RUB';
 

frontend/pshared/lib/provider/payment/quotation/quotation.dart

@@ -26,6 +26,7 @@ import 'package:pshared/service/payment/quotation.dart';
 import 'package:pshared/utils/payment/quote_helpers.dart';
 import 'package:pshared/utils/exception.dart';
 
+
 class QuotationProvider extends ChangeNotifier {
   static final _logger = Logger('provider.payment.quotation');
   Resource<PaymentQuote> _quotation = Resource(