Permissionless.js Quickstart Guide
In this guide, you will learn how to sponsor the deployment of an ERC-4337 Safe account and its user operations using Pimlico (opens in a new tab) infrastructure and the permissionless (opens in a new tab) library.
This guide focuses high-level on deploying and using Safe accounts configured with the Safe4337Module enabled. For a more detailed guide that shows what happens under the hood, check the Permissionless detailed guide.
Pimlico is one of the most popular ERC-4337 account abstraction infrastructure platforms, which provides a suite of tools and services to help build, deploy, and manage smart accounts on EVM-compatible chains.
permissionless is a TypeScript library focused on building with the ERC-4337 stack, including smart accounts, bundlers, paymasters, and user operations. Some of its core principles are providing a great developer experience and avoiding vendor lock-in by supporting different providers and ERC-4337 smart accounts, including Safe.
If you are already building with the Safe{Core} SDK, you may want to follow the Safe4337Pack guide instead of integrating the permissionless library directly into your application.
Prerequisites
- Node.js and npm (opens in a new tab).
- A Pimlico account (opens in a new tab) and an API key.
Install dependencies
Install viem (opens in a new tab) and permissionless (opens in a new tab) dependencies by running the following command:
_10pnpm install viem permissionless
Steps
Imports
These are all the imports required in the script we are building for this guide, which includes permissionless and viem packages.
_10import 'dotenv/config'_10import { ENTRYPOINT_ADDRESS_V06, createSmartAccountClient } from 'permissionless'_10import { signerToSafeSmartAccount } from 'permissionless/accounts'_10import {_10 createPimlicoBundlerClient,_10 createPimlicoPaymasterClient,_10} from 'permissionless/clients/pimlico'_10import { createPublicClient, http, Hex, encodeFunctionData, parseEther } from 'viem'_10import { privateKeyToAccount } from 'viem/accounts'_10import { gnosis } from 'viem/chains'
Setup
These are the constants that will be used in this guide. We have selected Gnosis as the chain, but other supported networks can be used. We also need the Pimlico API key and a private key we will use for the owner of the Safe.
_10// Network_10const chain = gnosis_10const chainName = 'gnosis'_10const SPONSORSHIP_POLICY_ID = '<insert_pimlico_sponsorship_policy_id>'_10_10// Keys_10const PIMLICO_API_KEY = process.env.PIMLICO_API_KEY_10const PRIVATE_KEY = process.env.PRIVATE_KEY as Hex
Create the signer
First, we need a signer instance that will be the owner of the Safe account once it is deployed.
_10const signer = privateKeyToAccount(PRIVATE_KEY as Hash)
Initialize the clients
We need to create a few client instances to query the blockchain network and operate with Pimlico infrastructure.
Firstly, we instantiate a standard publicClient instance for regular Ethereum RPC calls. To do this, we must first define the corresponding RPC URL, depending on our network.
_10const publicClient = createPublicClient({_10 transport: http(`https://rpc.ankr.com/${chainName}`)_10})
Secondly, we instantiate the bundlerClient using the Pimlico API v1, which is dedicated to the Bundler methods. This API requires a PIMLICO_API_KEY that we can get from their dashboard (opens in a new tab).
_10const bundlerClient = createPimlicoBundlerClient({_10 transport: http(`https://api.pimlico.io/v1/${chainName}/rpc?apikey=${PIMLICO_API_KEY}`),_10 entryPoint: ENTRYPOINT_ADDRESS_V06_10})
Lastly, we instantiate the paymasterClient using the Pimlico API v2, which is dedicated to the Paymaster methods and responsible for interacting with Pimlico's Verifying Paymaster endpoint and requesting sponsorship.
_10const paymasterClient = createPimlicoPaymasterClient({_10 transport: http(`https://api.pimlico.io/v2/${chainName}/rpc?apikey=${PIMLICO_API_KEY}`),_10 entryPoint: ENTRYPOINT_ADDRESS_V06_10})
Fetch the gas price
We fetch the current gas price values to add them later to our transaction.
_10const gasPrices = await bundlerClient.getUserOperationGasPrice()
Create the Safe account
We can create a Safe account based on our signer address, the entryPoint address, an optional saltNonce that will affect the resulting address of the deployed Safe, and the safeVersion (that must be 1.4.1 or higher).
_10const safeAccount = await signerToSafeSmartAccount(publicClient, {_10 entryPoint: ENTRYPOINT_ADDRESS_V06,_10 signer: signer,_10 saltNonce: 0n, // Optional_10 safeVersion: '1.4.1',_10 address: '0x...' // Optional. Only for existing Safe accounts._10})
The optional address parameter is only used when we already have a Safe account and want to initialize it. Deployments of new Safe accounts should remove this parameter.
Create the Safe account client
We need to create the smart account client with the following parameters:
_10const safeAccountClient = createSmartAccountClient({_10 account: safeAccount,_10 entryPoint: ENTRYPOINT_ADDRESS_V06,_10 chain: chain,_10 bundlerTransport: http(`https://api.pimlico.io/v1/${chainName}/rpc?apikey=${PIMLICO_API_KEY}`),_10 middleware: {_10 gasPrice: async () => (await bundlerClient.getUserOperationGasPrice()).fast,_10 sponsorUserOperation: paymasterClient.sponsorUserOperation_10 }_10})
In case we want to sponsor the transactions of this Safe using a Pimlico sponsorship id, we need to replace the sponsorUserOperation passed in the middleware property like this:
_10sponsorUserOperation: ({ userOperation }) => {_10 return paymasterClient.sponsorUserOperation({_10 userOperation,_10 sponsorshipPolicyId: SPONSORSHIP_POLICY_ID_10 })_10}
Submit a transaction
Finally, we call the sendTransaction method to submit our transaction.
_11const txHash = await safeAccountClient.sendTransaction({_11 to: safeAccount.address,_11 value: parseEther('0'),_11 data: encodeFunctionData({_11 abi: '',_11 functionName: '',_11 args: []_11 }),_11 maxFeePerGas: gasPrices.fast.maxFeePerGas,_11 maxPriorityFeePerGas: gasPrices.fast.maxPriorityFeePerGas_11})
Recap and further reading
This guide covered how to sponsor the deployment of a new ERC-4337 Safe and its user operations with Pimlico infrastructure using a Paymaster.
Feel free to try out other ideas and possibilities, as there are many more regarding:
- The deployment and initial setup of ERC-4337 accounts.
- The entity responsible for paying the transaction fees.
- The tokens used to pay the transaction fees.
Explore our 4337-gas-metering (opens in a new tab) repository on GitHub to see how most of these options work with Safe and notice the integrations with different providers like Alchemy, Gelato, and Pimlico.