Send Sync Transactions

Send transactions and wait for the final result in a single call. Sync methods are ideal for fast chains where you want immediate confirmation feedback.

Getting Started

Import Dependencies

import { createGelatoEvmRelayerClient } from '@gelatocloud/gasless';

Create Relayer Client

To create an API Key, visit the Gelato App and navigate to Relayer > API Keys.

const relayer = createGelatoEvmRelayerClient({
  apiKey: process.env.GELATO_API_KEY,
  testnet: true // Use false for mainnet
});

Send Sync Transaction

Submit a transaction and wait for the final result:

const receipt = await relayer.sendTransactionSync({
  chainId: 84532,
  to: '0xContractAddress',
  data: '0xCalldata',

  timeout: 30000  // Required: max wait time in ms
});

console.log('TX hash:', receipt.transactionHash);

Parameters

Parameter	Type	Required	Description
`chainId`	`number`	Yes	Target chain ID
`to`	`Address`	Yes	Target contract address
`data`	`Hex`	Yes	Transaction calldata
`authorizationList`	`Authorization[]`	No	EIP-7702 authorizations
`context`	`unknown`	No	Optional context (e.g., from fee quote)
`timeout`	`number`	Yes	Max wait time in milliseconds

Return Type

The sync method returns a TransactionReceipt directly on success, or throws an error on failure:

const receipt = await relayer.sendTransactionSync({
  chainId: 84532,
  to: '0xContractAddress',
  data: '0xCalldata',
  timeout: 30000
});

// receipt contains:
// - transactionHash: Hex
// - blockNumber: bigint
// - gasUsed: bigint
// - ... other receipt fields

Async vs Sync Comparison

Async (sendTransaction)
Sync (sendTransactionSync)

// Returns immediately with task ID
const taskId = await relayer.sendTransaction({
  chainId: 84532,
  to: '0xContract',
  data: '0xCalldata',
});

// Wait for receipt
try {
  const receipt = await relayer.waitForReceipt({ id: taskId });
  console.log(`Transaction hash: ${receipt.transactionHash}`);
} catch (error) {
  console.log(`Transaction failed: ${error.message}`);
}

// Waits and returns receipt directly
const receipt = await relayer.sendTransactionSync({
  chainId: 84532,
  to: '0xContract',
  data: '0xCalldata',

  timeout: 30000
});

Additional Resources

Sync Methods Overview - Feature overview
Payment Methods - Available payment options
Tracking Requests - How to track transaction status

Gelato Turbo Relayer

EVM Gasless Features

How-To Guides

Relayer API Endpoints

Additional Resources

Send Sync Transactions

Getting Started

Parameters

Return Type

Async vs Sync Comparison

Additional Resources

​Getting Started

​Parameters

​Return Type

​Async vs Sync Comparison

​Additional Resources

Getting Started

Parameters

Return Type

Async vs Sync Comparison

Additional Resources