diff --git a/internal/ethapi/transaction_args.go b/internal/ethapi/transaction_args.go
index 4fb30e6289..284a2ab308 100644
--- a/internal/ethapi/transaction_args.go
+++ b/internal/ethapi/transaction_args.go
@@ -40,6 +40,8 @@ import (
 // TransactionArgs represents the arguments to construct a new transaction
 // or a message call.
 type TransactionArgs struct {
+	Type                 *hexutil.Uint64 `json:"type,omitempty"`
+
 	From                 *common.Address `json:"from"`
 	To                   *common.Address `json:"to"`
 	Gas                  *hexutil.Uint64 `json:"gas"`
@@ -72,6 +74,24 @@ type TransactionArgs struct {
 	AuthorizationList []types.SetCodeAuthorization `json:"authorizationList"`
 }
 
+func (args *TransactionArgs) inferTxType(defaultType int) int {
+    usedType := types.LegacyTxType
+    switch {
+    case args.AuthorizationList != nil || defaultType == types.SetCodeTxType:
+        usedType = types.SetCodeTxType
+    case args.BlobHashes != nil || defaultType == types.BlobTxType:
+        usedType = types.BlobTxType
+    case args.MaxFeePerGas != nil || defaultType == types.DynamicFeeTxType:
+        usedType = types.DynamicFeeTxType
+    case args.AccessList != nil || defaultType == types.AccessListTxType:
+        usedType = types.AccessListTxType
+    }
+    if args.GasPrice != nil {
+        usedType = types.LegacyTxType
+    }
+    return usedType
+}
+
 // from retrieves the transaction sender address.
 func (args *TransactionArgs) from() common.Address {
 	if args.From == nil {
@@ -176,6 +196,32 @@ func (args *TransactionArgs) setDefaults(ctx context.Context, b Backend, config
 	} else {
 		args.ChainID = (*hexutil.Big)(want)
 	}
+
+	// Validate explicit transaction type if provided
+	if args.Type != nil {
+		requested := int(*args.Type)
+
+		// Validate supported types
+		switch requested {
+		case types.LegacyTxType,
+			types.AccessListTxType,
+			types.DynamicFeeTxType,
+			types.BlobTxType,
+			types.SetCodeTxType:
+			// ok
+		default:
+			return fmt.Errorf("unsupported transaction type: %d", requested)
+		}
+
+		inferred := args.inferTxType(types.LegacyTxType)
+
+		if requested != inferred {
+			return fmt.Errorf(
+				"transaction type mismatch (requested=%d inferred=%d)",
+				requested, inferred,
+			)
+		}
+	}
 	return nil
 }