ModuleSDK
Accounts
Kernel

How to use the Module SDK with the Kernel

The Kernel (opens in a new tab) is one of the most widely used smart accounts. In this tutorial, you will learn how to use the Module SDK with the Kernel.

Install the packages

npm i viem @rhinestone/module-sdk permissionless @zerodev/sdk @zerodev/ecdsa-validator

Create a signer

Create a to control the account with, in this case, we will use an EOA.

import { generatePrivateKey, privateKeyToAccount } from 'viem/accounts'
 
const main = async () => {
  const privateKey = generatePrivateKey()
  const signer = privateKeyToAccount(privateKey)
}

Create a validator

Each Kernel account handles validation through a smart contract known as a "validator." In this case, we will be using the ECDSA validator.

Add the following code to create the ECDSA validator:

import { signerToEcdsaValidator } from '@zerodev/ecdsa-validator'
 
const ecdsaValidator = await signerToEcdsaValidator(publicClient, {
  signer,
  entryPoint,
  kernelVersion: KERNEL_V3_1,
})

Create an account

Create the Kernel account object using the signer.

import { createKernelAccount } from '@zerodev/sdk'
 
const account = await createKernelAccount(publicClient, {
  plugins: {
    sudo: ecdsaValidator,
  },
  entryPoint,
}).extend(erc7579Actions({ entryPoint }))

Create the smart account client

The smart account client is used to interact with the smart account.

import { createKernelAccountClient } from '@zerodev/sdk'
 
const smartClient = createKernelAccountClient({
  account,
  chain,
  entryPoint,
  bundlerTransport: http(BUNDLER_RPC),
  middleware: {
    sponsorUserOperation: async ({ userOperation }) => {
      const zerodevPaymaster = createZeroDevPaymasterClient({
        chain,
        entryPoint,
        transport: http(PAYMASTER_RPC),
      })
      return zerodevPaymaster.sponsorUserOperation({
        userOperation,
        entryPoint,
      })
    },
  },
})

Create the module object

Get the module object for the module that you want to install on the smart account. In this case, we will install the Social Recovery Module. We will pass to it a number of guardians that can recover the account as well as a threshold of guardians required to recover the account.

import { getSocialRecoveryValidator } from '@rhinestone/module-sdk'
 
const module = getSocialRecoveryValidator({
  threshold: 2,
  guardians: ['0x1234...', '0x5678...'],
})

Install the module

With this module object, we can now install it on the smart account.

const context = encodePacked(
  ['address', 'bytes'],
  [
    module.hook ?? zeroAddress,
    encodeAbiParameters(
      [{ type: 'bytes' }, { type: 'bytes' }],
      [module.initData || '0x', '0x'],
    ),
  ],
)
 
const opHash = await smartClient.installModule({
  type: module.type,
  address: module.module,
  context,
})

Wait for the UserOperation to be confirmed

Let's wait until the UserOperation is confirmed, after which the module will be installed.

const bundlerClient = kernelClient.extend(bundlerActions(entryPoint))
await bundlerClient.waitForUserOperationReceipt({
  hash: userOpHash,
})
SafePermissionless.js