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

@@ -6,6 +6,7 @@ import (
 	"strings"
 
 	"github.com/tech/sendico/gateway/chain/internal/service/gateway/driver"
+	"github.com/tech/sendico/gateway/chain/internal/service/gateway/shared"
 	"github.com/tech/sendico/pkg/api/routers/gsresponse"
 	"github.com/tech/sendico/pkg/merrors"
 	"github.com/tech/sendico/pkg/mservice"
@@ -84,19 +85,28 @@ func (c *estimateTransferFeeCommand) Execute(ctx context.Context, req *chainv1.E
 		return gsresponse.InvalidArgument[chainv1.EstimateTransferFeeResponse](c.deps.Logger, mservice.ChainGateway, err)
 	}
 
+	walletForFee := sourceWallet
+	nativeCurrency := shared.NativeCurrency(networkCfg)
+	if nativeCurrency != "" && strings.EqualFold(nativeCurrency, amount.GetCurrency()) {
+		copyWallet := *sourceWallet
+		copyWallet.ContractAddress = ""
+		copyWallet.TokenSymbol = nativeCurrency
+		walletForFee = &copyWallet
+	}
+
 	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)
+	feeMoney, err := chainDriver.EstimateFee(ctx, driverDeps, networkCfg, walletForFee, 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) == "" {
+	if strings.TrimSpace(walletForFee.ContractAddress) == "" {
 		contextLabel = "native_transfer"
 	}
 	resp := &chainv1.EstimateTransferFeeResponse{

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

@@ -113,6 +113,14 @@ func (c *submitTransferCommand) Execute(ctx context.Context, req *chainv1.Submit
 	netAmount := shared.CloneMoney(amount)
 	netAmount.Amount = netDec.String()
 
+	effectiveTokenSymbol := sourceWallet.TokenSymbol
+	effectiveContractAddress := sourceWallet.ContractAddress
+	nativeCurrency := shared.NativeCurrency(networkCfg)
+	if nativeCurrency != "" && strings.EqualFold(nativeCurrency, amountCurrency) {
+		effectiveTokenSymbol = nativeCurrency
+		effectiveContractAddress = ""
+	}
+
 	transfer := &model.Transfer{
 		IdempotencyKey:  idempotencyKey,
 		TransferRef:     shared.GenerateTransferRef(),
@@ -120,8 +128,8 @@ func (c *submitTransferCommand) Execute(ctx context.Context, req *chainv1.Submit
 		SourceWalletRef: sourceWalletRef,
 		Destination:     destination,
 		Network:         sourceWallet.Network,
-		TokenSymbol:     sourceWallet.TokenSymbol,
+		TokenSymbol:     effectiveTokenSymbol,
-		ContractAddress: sourceWallet.ContractAddress,
+		ContractAddress: effectiveContractAddress,
 		RequestedAmount: shared.CloneMoney(amount),
 		NetAmount:       netAmount,
 		Fees:            fees,

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

@@ -119,6 +119,15 @@ func TransferStatusToProto(status model.TransferStatus) chainv1.TransferStatus {
 	}
 }
 
+// NativeCurrency returns the canonical native token symbol for a network.
+func NativeCurrency(network Network) string {
+	currency := strings.ToUpper(strings.TrimSpace(network.NativeToken))
+	if currency == "" {
+		currency = strings.ToUpper(strings.TrimSpace(network.Name))
+	}
+	return currency
+}
+
 // Network describes a supported blockchain network and known token contracts.
 type Network struct {
 	Name           string