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prepareUserOperation

Prepares a User Operation for execution and fills in missing properties.

Usage

example.ts
import { parseEther } from 'viem'
import { account, bundlerClient } from './config'
 
const userOperation = await bundlerClient.prepareUserOperation({ 
  account,
  calls: [{
    to: '0x70997970c51812dc3a010c7d01b50e0d17dc79c8',
    value: parseEther('1')
  }]
})

Account Hoisting

If you do not wish to pass an account to every prepareUserOperation, you can also hoist the Account on the Bundler Client (see config.ts).

Learn more.

example.ts
import { parseEther } from 'viem'
import { bundlerClient } from './config'
 
const userOperation = await bundlerClient.prepareUserOperation({ 
  calls: [{
    to: '0x70997970c51812dc3a010c7d01b50e0d17dc79c8',
    value: parseEther('1')
  }],
})

Contract Calls

The calls property also accepts Contract Calls, and can be used via the abi, functionName, and args properties.

example.ts
import { parseEther } from 'viem'
import { bundlerClient, publicClient } from './config'
import { wagmiAbi } from './abi'
 
const userOperation = await bundlerClient.prepareUserOperation({ 
  calls: [{
    abi: wagmiAbi,
    functionName: 'mint',
    to: '0xFBA3912Ca04dd458c843e2EE08967fC04f3579c2',
  }],
})

Returns

UserOperation

The prepared User Operation.

Parameters

account

  • Type: SmartAccount

The Account to use for User Operation execution.

const userOperation = await bundlerClient.prepareUserOperation({
  account, 
  calls: [{
    to: '0x70997970c51812dc3a010c7d01b50e0d17dc79c8',
    value: parseEther('1')
  }]
})

calls

  • Type: { data: Hex, to: Address, value: bigint }[]

The calls to execute in the User Operation.

const userOperation = await bundlerClient.prepareUserOperation({
  account,
  calls: [{ 
    to: '0x70997970c51812dc3a010c7d01b50e0d17dc79c8', 
    value: parseEther('1') 
  }] 
})

callGasLimit (optional)

  • Type: bigint

The amount of gas to allocate the main execution call.

const userOperation = await bundlerClient.prepareUserOperation({
  account,
  calls: [{
    to: '0x70997970c51812dc3a010c7d01b50e0d17dc79c8',
    value: parseEther('1')
  }],
  callGasLimit: 69420n, 
})

factory (optional)

  • Type: Address

Account Factory address.

const userOperation = await bundlerClient.prepareUserOperation({
  account,
  calls: [{
    to: '0x70997970c51812dc3a010c7d01b50e0d17dc79c8',
    value: parseEther('1')
  }],
  factory: '0x1234567890123456789012345678901234567890', 
  factoryData: '0xdeadbeef',
})

factoryData (optional)

  • Type: Hex

Call data to execute on the Account Factory to deploy a Smart Account.

const userOperation = await bundlerClient.prepareUserOperation({
  account,
  calls: [{
    to: '0x70997970c51812dc3a010c7d01b50e0d17dc79c8',
    value: parseEther('1')
  }],
  factory: '0x1234567890123456789012345678901234567890',
  factoryData: '0xdeadbeef', 
})

maxFeePerGas (optional)

  • Type: bigint

Maximum fee per gas for User Operation execution.

const userOperation = await bundlerClient.prepareUserOperation({
  account,
  calls: [{
    to: '0x70997970c51812dc3a010c7d01b50e0d17dc79c8',
    value: parseEther('1')
  }],
  maxFeePerGas: 420n, 
})

maxPriorityFeePerGas (optional)

  • Type: bigint

Maximum priority fee per gas for User Operation execution.

const userOperation = await bundlerClient.prepareUserOperation({
  account,
  calls: [{
    to: '0x70997970c51812dc3a010c7d01b50e0d17dc79c8',
    value: parseEther('1')
  }],
  maxPriorityFeePerGas: 420n, 
  maxFeePerGas: 10n, 
})

nonce (optional)

  • Type: bigint

Nonce for the User Operation.

const userOperation = await bundlerClient.prepareUserOperation({
  account,
  calls: [{
    to: '0x70997970c51812dc3a010c7d01b50e0d17dc79c8',
    value: parseEther('1')
  }],
  nonce: 10n, 
})

paymaster (optional)

  • Type: Address | true | PaymasterClient | PaymasterActions

Sets Paymaster configuration for the User Operation.

  • If paymaster: Address, it will use the provided Paymaster contract address for sponsorship.
  • If paymaster: PaymasterClient, it will use the provided Paymaster Client for sponsorship.
  • If paymaster: true, it will be assumed that the Bundler Client also supports Paymaster RPC methods (e.g. pm_getPaymasterData), and use them for sponsorship.
  • If custom functions are provided to paymaster, it will use them for sponsorship.

Using a Paymaster Contract Address

const hash = await bundlerClient.prepareUserOperation({
  account,
  calls: [{
    to: '0x70997970c51812dc3a010c7d01b50e0d17dc79c8',
    value: parseEther('1')
  }],
  paymaster: '0x942fD5017c0F60575930D8574Eaca13BEcD6e1bB', 
  paymasterData: '0xdeadbeef',
})

Using a Paymaster Client

const paymasterClient = createPaymasterClient({ 
  transport: http('https://api.pimlico.io/v2/1/rpc?apikey={API_KEY}') 
}) 
 
const hash = await bundlerClient.prepareUserOperation({
  account,
  calls: [{
    to: '0x70997970c51812dc3a010c7d01b50e0d17dc79c8',
    value: parseEther('1')
  }],
  paymaster: paymasterClient, 
})

Using the Bundler Client as Paymaster

const hash = await bundlerClient.prepareUserOperation({
  account,
  calls: [{
    to: '0x70997970c51812dc3a010c7d01b50e0d17dc79c8',
    value: parseEther('1')
  }],
  paymaster: true, 
})

paymasterContext (optional)

  • Type: unknown

Paymaster specific fields.

const paymasterClient = createPaymasterClient({
  transport: http('https://api.pimlico.io/v2/1/rpc?apikey={API_KEY}')
})
 
const hash = await bundlerClient.prepareUserOperation({
  account,
  calls: [{
    to: '0x70997970c51812dc3a010c7d01b50e0d17dc79c8',
    value: parseEther('1')
  }],
  paymaster: paymasterClient,
  paymasterContext: { 
    policyId: 'abc123'
  }, 
})

paymasterData (optional)

  • Type: Address

Call data to execute on the Paymaster contract.

const userOperation = await bundlerClient.prepareUserOperation({
  account,
  calls: [{
    to: '0x70997970c51812dc3a010c7d01b50e0d17dc79c8',
    value: parseEther('1')
  }],
  paymaster: '0x942fD5017c0F60575930D8574Eaca13BEcD6e1bB',
  paymasterData: '0xdeadbeef', 
})

paymasterPostOpGasLimit (optional)

  • Type: bigint

The amount of gas to allocate for the Paymaster post-operation code.

const userOperation = await bundlerClient.prepareUserOperation({
  account,
  calls: [{
    to: '0x70997970c51812dc3a010c7d01b50e0d17dc79c8',
    value: parseEther('1')
  }],
  paymaster: '0x942fD5017c0F60575930D8574Eaca13BEcD6e1bB',
  paymasterData: '0xdeadbeef',
  paymasterPostOpGasLimit: 69420n, 
})

paymasterVerificationGasLimit (optional)

  • Type: bigint

The amount of gas to allocate for the Paymaster validation code.

const userOperation = await bundlerClient.prepareUserOperation({
  account,
  calls: [{
    to: '0x70997970c51812dc3a010c7d01b50e0d17dc79c8',
    value: parseEther('1')
  }],
  paymaster: '0x942fD5017c0F60575930D8574Eaca13BEcD6e1bB',
  paymasterData: '0xdeadbeef',
  paymasterVerificationGasLimit: 69420n, 
})

preVerificationGas (optional)

  • Type: bigint

Extra gas to pay the Bundler.

const userOperation = await bundlerClient.prepareUserOperation({
  account,
  calls: [{
    to: '0x70997970c51812dc3a010c7d01b50e0d17dc79c8',
    value: parseEther('1')
  }],
  preVerificationGas: 69420n, 
})

signature (optional)

  • Type: Hex

Signature for the User Operation.

const userOperation = await bundlerClient.prepareUserOperation({
  account,
  calls: [{
    to: '0x70997970c51812dc3a010c7d01b50e0d17dc79c8',
    value: parseEther('1')
  }],
  signature: '0x...', 
})

verificationGasLimit (optional)

  • Type: bigint

The amount of gas to allocate for the verification step.

const userOperation = await bundlerClient.prepareUserOperation({
  account,
  calls: [{
    to: '0x70997970c51812dc3a010c7d01b50e0d17dc79c8',
    value: parseEther('1')
  }],
  verificationGasLimit: 69420n, 
})