Integration with Gelato

The Gelato relay (opens in a new tab) allows developers to execute gasless transactions.

Prerequisites

Node.js and npm (opens in a new tab).
Have a Safe account configured with threshold equal to 1, where only one signature is needed to execute transactions.
To use Gelato 1Balance an API key (opens in a new tab) is required.

Install dependencies

yarn add ethers @safe-global/relay-kit @safe-global/protocol-kit @safe-global/types-kit

Relay Kit options

Currently, the Relay Kit is only compatible with the Gelato relay (opens in a new tab). The Gelato relay can be used in two ways:

Gelato 1Balance

Gelato 1Balance (opens in a new tab) allows you to execute transactions using a prepaid deposit. This can be used to sponsor transactions to other Safes or even to use a deposit on Polygon to pay the fees for a wallet on another chain.

For the 1Balance quickstart tutorial, you will use the Gelato relayer to pay for the gas fees on BNB Chain using the Polygon USDC you have deposited into your Gelato 1Balance account.

Setup

Start with a 1/1 Safe on BNB Chain (opens in a new tab).
Deposit Polygon USDC into Gelato 1Balance (opens in a new tab) (transaction 0xa5f38 (opens in a new tab)).
The Safe owner 0x6Dbd26Bca846BDa60A90890cfeF8fB47E7d0f22c (opens in a new tab) signs a transaction to send 0.0005 BNB and submits it to Gelato relay.
Track the relay request (opens in a new tab) of Gelato Task ID 0x1bf7 (opens in a new tab).
Transaction 0x814d3 (opens in a new tab) is executed on the blockchain.

Use a Safe as the Relay

While using Gelato, you can specify that you only want the relay to allow transactions from specific smart contracts. If one of those smart contracts is a Safe smart contract, you will need to either verify the contract on a block explorer or get the ABI of the contract implementation (not the ABI of the smart contract address). This is because the Safe smart contracts use the Proxy Pattern (opens in a new tab), so the implementation logic for your smart contract exists on a different address.

Imports

import { ethers } from 'ethers'
import { GelatoRelayPack } from '@safe-global/relay-kit'
import Safe from '@safe-global/protocol-kit'
import {
  MetaTransactionData,
  MetaTransactionOptions
} from '@safe-global/types-kit'

Initialize the transaction settings

Modify the variables to customize to match your desired transaction settings.

// https://chainlist.org
const RPC_URL = 'https://endpoints.omniatech.io/v1/bsc/mainnet/public'
const OWNER_PRIVATE_KEY = process.env.OWNER_PRIVATE_KEY
const safeAddress = '0x...' // Safe from which the transaction will be sent

// Any address can be used for destination. In this example, we use vitalik.eth
const destinationAddress = '0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045'
const withdrawAmount = ethers.parseUnits('0.005', 'ether').toString()

Create a transaction

// Create a transactions array with one transaction object
const transactions: MetaTransactionData[] = [{
  to: destinationAddress,
  data: '0x',
  value: withdrawAmount
}]

const options: MetaTransactionOptions = {
  isSponsored: true
}

Instantiate the Protocol Kit and Relay Kit

const protocolKit = await Safe.init({
  provider: RPC_URL,
  signer: OWNER_PRIVATE_KEY,
  safeAddress
})

const relayKit = new GelatoRelayPack({
  apiKey: process.env.GELATO_RELAY_API_KEY!,
  protocolKit
})

Prepare the transaction

const safeTransaction = await relayKit.createTransaction({
  transactions,
  options
})

const signedSafeTransaction = await protocolKit.signTransaction(safeTransaction)

Send the transaction to the relay

const response = await relayKit.executeTransaction({
  executable: signedSafeTransaction,
  options
})

console.log(`Relay Transaction Task ID: https://relay.gelato.digital/tasks/status/${response.taskId}`)

Gelato SyncFee

Gelato SyncFee (opens in a new tab) allows you to execute a transaction and pay the gas fees directly with funds in your Safe, even if you don't have ETH or the native blockchain token.

For the SyncFee quickstart tutorial, you will use the Gelato relayer to pay for the gas fees on the BNB Chain using the BNB you hold in your Safe. No need to have funds on your signer.