Updated on 2026-08-14

core/datasource/src/main/java/com/tangem/datasource/api/gasless/GaslessTxServiceApi.kt

@@ -2,11 +2,20 @@ package com.tangem.datasource.api.gasless
 
 import com.tangem.datasource.api.common.response.ApiResponse
 import com.tangem.datasource.api.gasless.models.GaslessServiceResponse
+import com.tangem.datasource.api.gasless.models.GaslessSignedTransactionResult
 import com.tangem.datasource.api.gasless.models.GaslessSupportedTokens
+import com.tangem.datasource.api.gasless.models.GaslessTransactionRequest
+import retrofit2.http.Body
 import retrofit2.http.GET
+import retrofit2.http.POST
 
 interface GaslessTxServiceApi {
 
     @GET("api/v1/tokens")
     suspend fun getSupportedTokens(): ApiResponse<GaslessServiceResponse<GaslessSupportedTokens>>
+
+    @POST("api/v1/sign")
+    suspend fun signGaslessTransaction(
+        @Body transaction: GaslessTransactionRequest,
+    ): ApiResponse<GaslessServiceResponse<GaslessSignedTransactionResult>>
 }

core/datasource/src/main/java/com/tangem/datasource/api/gasless/models/GaslessSignedTransactionResult.kt

@@ -0,0 +1,23 @@
+package com.tangem.datasource.api.gasless.models
+
+import com.squareup.moshi.Json
+import com.squareup.moshi.JsonClass
+
+/**
+ * Result of gasless transaction signing.
+ * Contains the signed transaction data and gas parameters.
+ */
+@JsonClass(generateAdapter = true)
+data class GaslessSignedTransactionResult(
+    @Json(name = "signedTransaction")
+    val signedTransaction: String,
+
+    @Json(name = "gasLimit")
+    val gasLimit: String,
+
+    @Json(name = "maxFeePerGas")
+    val maxFeePerGas: String,
+
+    @Json(name = "maxPriorityFeePerGas")
+    val maxPriorityFeePerGas: String,
+)

core/datasource/src/main/java/com/tangem/datasource/api/gasless/models/GaslessTransactionRequest.kt

@@ -0,0 +1,93 @@
+package com.tangem.datasource.api.gasless.models
+
+import com.squareup.moshi.Json
+import com.squareup.moshi.JsonClass
+
+/**
+ * Request body for gasless transaction submission.
+ * Represents complete transaction with fee delegation metadata.
+ */
+@JsonClass(generateAdapter = true)
+data class GaslessTransactionRequest(
+    @Json(name = "gaslessTransaction")
+    val gaslessTransaction: GaslessTransactionData,
+
+    @Json(name = "signature")
+    val signature: String,
+
+    @Json(name = "userAddress")
+    val userAddress: String,
+
+    @Json(name = "chainId")
+    val chainId: Int,
+
+    @Json(name = "eip7702auth")
+    val eip7702Auth: Eip7702Authorization? = null,
+)
+
+@JsonClass(generateAdapter = true)
+data class GaslessTransactionData(
+    @Json(name = "transaction")
+    val transaction: TransactionData,
+
+    @Json(name = "fee")
+    val fee: FeeData,
+
+    @Json(name = "nonce")
+    val nonce: String,
+)
+
+@JsonClass(generateAdapter = true)
+data class TransactionData(
+    @Json(name = "to")
+    val to: String,
+
+    @Json(name = "value")
+    val value: String,
+
+    @Json(name = "data")
+    val data: String,
+)
+
+@JsonClass(generateAdapter = true)
+data class FeeData(
+    @Json(name = "feeToken")
+    val feeToken: String,
+
+    @Json(name = "maxTokenFee")
+    val maxTokenFee: String,
+
+    @Json(name = "coinPriceInToken")
+    val coinPriceInToken: String,
+
+    @Json(name = "feeTransferGasLimit")
+    val feeTransferGasLimit: String,
+
+    @Json(name = "baseGas")
+    val baseGas: String,
+)
+
+/**
+ * EIP-7702 authorization for account abstraction.
+ * Optional field, used only when EOA delegation is required.
+ */
+@JsonClass(generateAdapter = true)
+data class Eip7702Authorization(
+    @Json(name = "chainId")
+    val chainId: Int,
+
+    @Json(name = "address")
+    val address: String,
+
+    @Json(name = "nonce")
+    val nonce: String,
+
+    @Json(name = "yParity")
+    val yParity: Int,
+
+    @Json(name = "r")
+    val r: String,
+
+    @Json(name = "s")
+    val s: String,
+)