`userOperation.prepare`

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

Usage

import {  } from 'viem/utils'
import { ,  } from './config'
 
const  = await ..({
  ,
  : [{
    : '0x70997970c51812dc3a010c7d01b50e0d17dc79c8',
    : .('1')
  }]
})

import { ,  } from 'viem'
import { ,  } from 'viem/erc4337'
import {  } from 'viem'
import {  } from 'viem/chains'
 
const  = .({
  : ,
  : ()
})
 
export const  = await .({
  ,
  : .('0x...'),
})
 
export const  = .({
  ,
  : ('https://public.pimlico.io/v2/1/rpc')
})

Pass either calls for Smart Account encoding or an already encoded callData. Viem fills the remaining version-specific User Operation fields selected by parameters.

Account Hoisting

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

Learn more.

import {  } from 'viem/utils'
import {  } from './config'
 
const  = await ..({
  : [{
    : '0x70997970c51812dc3a010c7d01b50e0d17dc79c8',
    : .('1')
  }],
})

import { ,  } from 'viem'
import { ,  } from 'viem/erc4337'
import {  } from 'viem'
import {  } from 'viem/chains'
 
const  = .({
  : ,
  : ()
})
 
export const  = await .({
  ,
  : .('0x...'),
})
 
export const  = .({
  ,
  ,
  : ('https://public.pimlico.io/v2/1/rpc')
})

Contract Calls

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

import {  } from './config'
import {  } from './abi'
 
const  = await ..({
  : [{
    : ,
    : 'mint',
    : '0xFBA3912Ca04dd458c843e2EE08967fC04f3579c2',
  }],
})

export const  = [
  // ...
  {
    : [],
    : "mint",
    : [],
    : "nonpayable",
    : "function",
  },
  // ...
] as ;

import { ,  } from 'viem'
import { ,  } from 'viem/erc4337'
import {  } from 'viem'
import {  } from 'viem/chains'
 
const  = .({
  : ,
  : ()
})
 
export const  = await .({
  ,
  : .('0x...'),
})
 
export const  = .({
  ,
  ,
  : ('https://public.pimlico.io/v2/1/rpc')
})

Returns

UserOperation

The prepared User Operation.

Parameters

account

Type: SmartAccount
Default: bundlerClient.account

The Account to use for User Operation execution.

import {  } from 'viem/utils'
import { ,  } from './config'
const  = await ..({
  ,
  : [{
    : '0x70997970c51812dc3a010c7d01b50e0d17dc79c8',
    : .('1')
  }]
})

authorization

Type: Authorization.Signed

Signed EIP-7702 authorization for a delegated account.

callGasLimit

Type: bigint

The amount of gas to allocate the main execution call.

import { ,  } from './config'
import {  } from 'viem/utils'
const  = await ..({
  ,
  : [{
    : '0x70997970c51812dc3a010c7d01b50e0d17dc79c8',
    : .('1')
  }],
  : 69420n,
})

calls

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

The calls to execute in the User Operation.

import { ,  } from './config'
import {  } from 'viem/utils'
const  = await ..({
  ,
  : [{
    : '0x70997970c51812dc3a010c7d01b50e0d17dc79c8',
    : .('1')
  }]
})

You can also pass raw call data via the callData property:

import { ,  } from './config'
const  = await ..({
  ,
  : '0xdeadbeef',
})

dataSuffix

Type: Hex

Data to append to the end of User Operation calldata. Useful for adding transaction attribution.

If not provided, the dataSuffix configured on the Bundler Client (or inherited from the underlying client) will be used.

import { ,  } from './config'
import {  } from 'viem/utils'
const  = await ..({
  ,
  : [{
    : '0x70997970c51812dc3a010c7d01b50e0d17dc79c8',
    : .('1')
  }],
  : '0xdeadbeef',
})

factory

Type: Address

Account Factory address.

import { ,  } from './config'
import {  } from 'viem/utils'
const  = await ..({
  ,
  : [{
    : '0x70997970c51812dc3a010c7d01b50e0d17dc79c8',
    : .('1')
  }],
  : '0x1234567890123456789012345678901234567890',
  : '0xdeadbeef',
})

factoryData

Type: Hex

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

import { ,  } from './config'
import {  } from 'viem/utils'
const  = await ..({
  ,
  : [{
    : '0x70997970c51812dc3a010c7d01b50e0d17dc79c8',
    : .('1')
  }],
  : '0x1234567890123456789012345678901234567890',
  : '0xdeadbeef',
})

maxFeePerGas

Type: bigint

Maximum fee per gas for User Operation execution.

import { ,  } from './config'
import {  } from 'viem/utils'
const  = await ..({
  ,
  : [{
    : '0x70997970c51812dc3a010c7d01b50e0d17dc79c8',
    : .('1')
  }],
  : 420n,
})

maxPriorityFeePerGas

Type: bigint

Maximum priority fee per gas for User Operation execution.

import { ,  } from './config'
import {  } from 'viem/utils'
const  = await ..({
  ,
  : [{
    : '0x70997970c51812dc3a010c7d01b50e0d17dc79c8',
    : .('1')
  }],
  : 420n,
  : 10n,
})

nonce

Type: bigint

Nonce for the User Operation.

import { ,  } from './config'
import {  } from 'viem/utils'
const  = await ..({
  ,
  : [{
    : '0x70997970c51812dc3a010c7d01b50e0d17dc79c8',
    : .('1')
  }],
  : 10n,
})

parameters

Type: ('authorization' | 'factory' | 'fees' | 'gas' | 'nonce' | 'paymaster' | 'signature')[]
Default: All parameters

Fields that Viem should populate. Fields excluded from this list remain optional in the return type.

paymaster

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

import { ,  } from './config'
import {  } from 'viem/utils'
const  = await ..({
  ,
  : [{
    : '0x70997970c51812dc3a010c7d01b50e0d17dc79c8',
    : .('1')
  }],
  : '0x942fD5017c0F60575930D8574Eaca13BEcD6e1bB',
  : '0xdeadbeef',
})

Using a Paymaster Client

import { ,  } from './config'
import {  } from 'viem'
import {  } from 'viem/utils'
import {  } from 'viem/erc4337'
const  = .({
  : ('https://api.pimlico.io/v2/1/rpc?apikey={API_KEY}')
})
 
const  = await ..({
  ,
  : [{
    : '0x70997970c51812dc3a010c7d01b50e0d17dc79c8',
    : .('1')
  }],
  : ,
})

Using the Bundler Client as Paymaster

import { ,  } from './config'
import {  } from 'viem/utils'
const  = await ..({
  ,
  : [{
    : '0x70997970c51812dc3a010c7d01b50e0d17dc79c8',
    : .('1')
  }],
  : true,
})

paymasterContext

Type: unknown

Paymaster specific fields.

import { ,  } from './config'
import {  } from 'viem'
import {  } from 'viem/utils'
import {  } from 'viem/erc4337'
const  = .({
  : ('https://api.pimlico.io/v2/1/rpc?apikey={API_KEY}')
})
 
const  = await ..({
  ,
  : [{
    : '0x70997970c51812dc3a010c7d01b50e0d17dc79c8',
    : .('1')
  }],
  : ,
  : {
    : 'abc123'
  },
})

paymasterData

Type: Address

Call data to execute on the Paymaster contract.

import { ,  } from './config'
import {  } from 'viem/utils'
const  = await ..({
  ,
  : [{
    : '0x70997970c51812dc3a010c7d01b50e0d17dc79c8',
    : .('1')
  }],
  : '0x942fD5017c0F60575930D8574Eaca13BEcD6e1bB',
  : '0xdeadbeef',
})

paymasterPostOpGasLimit

Type: bigint

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

import { ,  } from './config'
import {  } from 'viem/utils'
const  = await ..({
  ,
  : [{
    : '0x70997970c51812dc3a010c7d01b50e0d17dc79c8',
    : .('1')
  }],
  : '0x942fD5017c0F60575930D8574Eaca13BEcD6e1bB',
  : '0xdeadbeef',
  : 69420n,
})

paymasterSignature

Type: Hex

EntryPoint 0.9 Paymaster signature. It is preserved separately from paymasterData and excluded from the account-signed User Operation hash.

paymasterVerificationGasLimit

Type: bigint

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

import { ,  } from './config'
import {  } from 'viem/utils'
const  = await ..({
  ,
  : [{
    : '0x70997970c51812dc3a010c7d01b50e0d17dc79c8',
    : .('1')
  }],
  : '0x942fD5017c0F60575930D8574Eaca13BEcD6e1bB',
  : '0xdeadbeef',
  : 69420n,
})

preVerificationGas

Type: bigint

Extra gas to pay the Bundler.

import { ,  } from './config'
import {  } from 'viem/utils'
const  = await ..({
  ,
  : [{
    : '0x70997970c51812dc3a010c7d01b50e0d17dc79c8',
    : .('1')
  }],
  : 69420n,
})

signature

Type: Hex

Signature for the User Operation.

import { ,  } from './config'
import {  } from 'viem/utils'
const  = await ..({
  ,
  : [{
    : '0x70997970c51812dc3a010c7d01b50e0d17dc79c8',
    : .('1')
  }],
  : '0x...',
})

stateOverride

Type: StateOverrides

The state override set is an optional address-to-state mapping, where each entry specifies some state to be ephemerally overridden prior to executing the call.

import { ,  } from './config'
import {  } from 'viem/utils'
const  = await ..({
  ,
  : [{
    : '0x70997970c51812dc3a010c7d01b50e0d17dc79c8',
    : .('1')
  }],
  : {
    '0xa5cc3c03994DB5b0d9A5eEdD10CabaB0813678AC': {
      : .('1'),
      : {
        '0x3ea2f1d0abf3fc66cf29eebb70cbd4e7fe762ef8a09bcc06c8edf641230afec0': '0x00000000000000000000000000000000000000000000000000000000000001a4',
      },
    },
  },
})

verificationGasLimit

Type: bigint

The amount of gas to allocate for the verification step.

import { ,  } from './config'
import {  } from 'viem/utils'
const  = await ..({
  ,
  : [{
    : '0x70997970c51812dc3a010c7d01b50e0d17dc79c8',
    : .('1')
  }],
  : 69420n,
})

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