> ## Documentation Index > Fetch the complete documentation index at: https://docs.swaps.xyz/llms.txt > Use this file to discover all available pages before exploring further. # Submit Gasless Transaction > Submits signed executions obtained from a gasless `GET /getAction` response for relay broadcast. The backend validates each signature, simulates the transactions, then broadcasts them via the configured relay provider. Call this endpoint only when `executionsType` is `GASLESS` in the `getAction` response. Sign all items in the `executions` array in order before submitting. ## OpenAPI ````yaml /swap-api-reference/openapi.json post /submitTx openapi: 3.1.0 info: title: Swaps API description: >- The Swaps API provides instant cross-chain swap and bridge functionality for decentralized applications. It supports multiple virtual machines (EVM, Solana, Bitcoin) and various DEX protocols and bridge solutions. version: 3.0.0 contact: name: Swaps.xyz url: https://swaps.xyz servers: - url: https://api-v2.swaps.xyz/api description: Production server security: - ApiKeyAuth: [] paths: /submitTx: post: summary: Submit Gasless Transaction description: >- Submits signed executions obtained from a gasless `GET /getAction` response for relay broadcast. The backend validates each signature, simulates the transactions, then broadcasts them via the configured relay provider. Call this endpoint only when `executionsType` is `GASLESS` in the `getAction` response. Sign all items in the `executions` array in order before submitting. operationId: submitTx requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/SubmitTxRequest' responses: '200': description: Transaction accepted for relay broadcast content: application/json: schema: $ref: '#/components/schemas/SubmitTxResponse' '400': description: >- Bad request — invalid signature, unknown txId, or malformed executions content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '401': description: Unauthorized — missing or invalid API key content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' security: - ApiKeyAuth: [] servers: - url: https://api-v2.swaps.xyz/api description: Core Swap API server components: schemas: SubmitTxRequest: type: object required: - txId - chainId - executions properties: txId: type: string description: >- The `txId` from the `GET /getAction` quote response. Used to correlate the signed executions with the original action on the relay. chainId: $ref: '#/components/schemas/ChainId' description: Source chain ID of the swap. executions: type: array description: >- All execution steps from the `getAction` response, each with a `signature` field populated by the user's wallet. Must be in the same order as returned by `getAction`. items: $ref: '#/components/schemas/Execution' SubmitTxResponse: type: object required: - success properties: success: type: boolean description: Whether the relay broadcast was accepted. txId: type: string description: >- Internal transaction ID. Pass this to `GET /getStatus` to poll for completion — the status endpoint will return the on-chain transaction hash once the relay broadcast confirms. error: type: string description: Error message when `success` is `false`. ErrorResponse: type: object required: - success - error properties: success: type: boolean description: Always false for error responses enum: - false example: false error: type: object required: - code - name - message - title - statusCode - timestamp properties: code: type: string description: Error type code for programmatic handling name: type: string description: Error class name message: type: string description: Detailed error message title: type: string description: Short, user-friendly error title statusCode: type: integer description: HTTP status code details: type: object description: Additional error details additionalProperties: true timestamp: type: string description: ISO 8601 timestamp when the error occurred ChainId: type: integer description: Chain ID. Find in the list of supported networks. Execution: description: >- A single signing step returned in the `executions` array of a gasless `getAction` response. Only available for Tron same-chain swaps. The client must sign each item in order and include the signatures when calling `POST /submitTx`. oneOf: - $ref: '#/components/schemas/EvmTransactionSignExecution' - $ref: '#/components/schemas/EvmSignTypedDataExecution' discriminator: propertyName: txType mapping: evmTransactionSign: $ref: '#/components/schemas/EvmTransactionSignExecution' evmSignTypedData: $ref: '#/components/schemas/EvmSignTypedDataExecution' EvmTransactionSignExecution: type: object required: - txType - data - signature properties: txType: type: string enum: - evmTransactionSign data: type: string description: >- JSON string of an unsigned Tron transaction (TronWeb `raw_data` shape) signature: type: string description: Hex-encoded signature from TronLink or compatible Tron wallet EvmSignTypedDataExecution: type: object required: - txType - data - signature properties: txType: type: string enum: - evmSignTypedData data: description: >- EIP-712 typed data to sign. Accepted as either a JSON string (same format returned by `GET /getAction`) or a parsed object — both are equivalent. oneOf: - type: string description: JSON-encoded EIP-712 typed data - $ref: '#/components/schemas/Eip712Data' signature: type: string description: Hex-encoded EIP-712 signature Eip712Data: type: object required: - domain - types - message properties: domain: $ref: '#/components/schemas/Eip712Domain' types: type: object description: EIP-712 type definitions (field name → array of {name, type} pairs) additionalProperties: type: array items: type: object properties: name: type: string type: type: string message: type: object description: The typed data message payload additionalProperties: true Eip712Domain: type: object required: - name - version - chainId - verifyingContract properties: name: type: string description: EIP-712 domain name version: type: string description: EIP-712 domain version chainId: type: integer description: Chain ID the typed data is bound to verifyingContract: type: string description: Address of the contract verifying the signature securitySchemes: ApiKeyAuth: type: apiKey in: header name: x-api-key description: 'Limited demo key for API Reference: `5c951bc81da566bbd030ba8e20724063`.' ````