Sending Transactions with EIP-7702

The guide below demonstrates how to send EIP-7702 Transactions to invoke Contract functions on an Externally Owned Account.

Overview

Here is an end-to-end overview of how to broadcast an EIP-7702 Transaction to send a batch of Calls. We will break it down into Steps below.

example.ts

import { parseEther } from 'viem'
import { walletClient } from './config'
import { abi, contractAddress } from './contract'
 
// 1. Authorize injection of the Contract's bytecode into our Account.
const authorization = await walletClient.signAuthorization({
  contractAddress,
})
 
// 2. Invoke the Contract's `execute` function to perform batch calls.
const hash = await walletClient.sendTransaction({
  authorizationList: [authorization],
  data: encodeFunctionData({
    abi,
    functionName: 'execute',
    args: [
      [
        {
          data: '0x',
          to: '0xcb98643b8786950F0461f3B0edf99D88F274574D',
          value: parseEther('0.001'),
        },
        {
          data: '0x',
          to: '0xd2135CfB216b74109775236E36d4b433F1DF507B', 
          value: parseEther('0.002'), 
        },  
      ],
    ]
  }),
  to: walletClient.account.address,
})

Steps

0. Install & Run Anvil

EIP-7702 is currently not supported on Ethereum Mainnet or Testnets, so let's set up an EIP-7702 compatible network. We will use an Anvil node for this example. If you are using an existing EIP-7702 compatible network, you can skip this step.

curl -L https://foundry.paradigm.xyz | bash
anvil --hardfork prague

1. Set up Smart Contract

We will need to set up a Smart Contract to interact with. For the purposes of this guide, we will create and deploy a BatchCallInvoker.sol contract, however, you can use any existing deployed contract.

Firstly, deploy a Contract to the Network with the following source:

BatchCallInvoker.sol

pragma solidity ^0.8.20;
 
contract BatchCallInvoker {
  struct Call {
    bytes data;
    address to;
    uint256 value;
  }
 
  function execute(Call[] calldata calls) external payable {
    for (uint256 i = 0; i < calls.length; i++) {
      Call memory call = calls[i];
      (bool success, ) = call.to.call{value: call.value}(call.data);
      require(success, "call reverted");
    }
  }
}

2. Set up Client & Account

Next, we will need to set up a Client and Externally Owned Account to sign EIP-7702 Authorizations.

This code snippet uses the Extending Client guide.

config.ts

import { createWalletClient, http } from 'viem'
import { anvil } from 'viem/chains'
import { privateKeyToAccount } from 'viem/accounts'
import { eip7702Actions } from 'viem/experimental'
 
export const account = privateKeyToAccount('0x...')
 
export const walletClient = createWalletClient({
  account,
  chain: anvil,
  transport: http(),
}).extend(eip7702Actions())

3. Authorize Contract Bytecode Injection

We will need to sign an Authorization to authorize the injection of the Contract's bytecode onto the Account.

In the example below, we are using the account attached to the walletClient to sign the Authorization – this will be the Account that the Contract's bytecode will be injected into.

example.ts

import { walletClient } from './config'
import { contractAddress } from './contract'
 
const authorization = await walletClient.signAuthorization({ 
  contractAddress, 
})

4. Invoke Contract Function

We can now perform batch calls by sending a Transaction to the Account (account) with the Authorization (authorizationList).

example.ts

import { encodeFunctionData, parseEther } from 'viem'
import { walletClient } from './config'
import { contractAddress } from './contract'
 
const authorization = await walletClient.signAuthorization({
  contractAddress,
})
 
const hash = await walletClient.sendTransaction({ 
  authorizationList: [authorization], 
  data: encodeFunctionData({ 
    abi, 
    functionName: 'execute', 
    args: [ 
      [ 
        { 
          data: '0x', 
          to: '0xcb98643b8786950F0461f3B0edf99D88F274574D', 
          value: parseEther('0.001'), 
        }, 
        { 
          data: '0x', 
          to: '0xd2135CfB216b74109775236E36d4b433F1DF507B', 
          value: parseEther('0.002'), 
        }, 
      ], 
    ] 
  }), 
  to: walletClient.account.address, 
})

5. Optional: Use an Invoker

We can also utilize an Invoker Account to execute a call on behalf of the authorizing Account. This is useful for cases where we want to "sponsor" the Transaction for the user (i.e. pay for their gas fees).

example.ts

// @filename: contract.ts
export const abi = [
  {
    "type": "function",
    "name": "execute",
    "inputs": [
      {
        "name": "calls",
        "type": "tuple[]",
        "components": [
          {
            "name": "data",
            "type": "bytes",
          },
          {
            "name": "to",
            "type": "address",
          },
          {
            "name": "value",
            "type": "uint256",
          }
        ]
      }
    ],
    "outputs": [],
    "stateMutability": "payable"
  },
] as const
 
export const contractAddress = '0x...'
// @filename: contract.ts
export const abi = [
  {
    "type": "function",
    "name": "execute",
    "inputs": [
      {
        "name": "calls",
        "type": "tuple[]",
        "components": [
          {
            "name": "data",
            "type": "bytes",
          },
          {
            "name": "to",
            "type": "address",
          },
          {
            "name": "value",
            "type": "uint256",
          }
        ]
      }
    ],
    "outputs": [],
    "stateMutability": "payable"
  },
] as const
 
export const contractAddress = '0x...'
// @filename: contract.ts
export const abi = [
  {
    "type": "function",
    "name": "execute",
    "inputs": [
      {
        "name": "calls",
        "type": "tuple[]",
        "components": [
          {
            "name": "data",
            "type": "bytes",
          },
          {
            "name": "to",
            "type": "address",
          },
          {
            "name": "value",
            "type": "uint256",
          }
        ]
      }
    ],
    "outputs": [],
    "stateMutability": "payable"
  },
] as const
 
export const contractAddress = '0x...'
// @filename: config.ts
import { createWalletClient, http } from 'viem'
import { anvil } from 'viem/chains'
import { privateKeyToAccount } from 'viem/accounts' 
import { eip7702Actions } from 'viem/experimental'
 
export const account = privateKeyToAccount('0x...')
 
export const walletClient = createWalletClient({
  account,
  chain: anvil,
  transport: http(),
}).extend(eip7702Actions())
// @filename: contract.ts
export const abi = [
  {
    "type": "function",
    "name": "execute",
    "inputs": [
      {
        "name": "calls",
        "type": "tuple[]",
        "components": [
          {
            "name": "data",
            "type": "bytes",
          },
          {
            "name": "to",
            "type": "address",
          },
          {
            "name": "value",
            "type": "uint256",
          }
        ]
      }
    ],
    "outputs": [],
    "stateMutability": "payable"
  },
] as const
 
export const contractAddress = '0x...'
// @filename: example.js
 
// ---cut---
import { encodeFunctionData{ parseEther } from 'viem'
import { walletClient } from './config'
import { contractAddress } from './contract'
 
const authorization = await walletClient.signAuthorization({
  contractAddress,
})
 
const invoker = privateKeyToAccount('0x...') 
 
const hash = await walletClient.sendTransaction({
  account: invoker, 
  authorizationList: [authorization],
  data: encodeFunctionData({
    abi,
    functionName: 'execute',
    args: [
      [
        {
          data: '0x',
          to: '0xcb98643b8786950F0461f3B0edf99D88F274574D',
          value: parseEther('0.001'),
        },
        {
         data: '0x',
          to: '0xd2135CfB216b74109775236E36d4b433F1DF507B',
          value: parseEther('0.002'),
        },
      ],
    ]
  }),
  to: walletClient.account.address,
})## Errors were thrown in the sample, but not included in an error tag

These errors were not marked as being expected: 1005. 
Expected: // @errors: 1005

Compiler Errors:

example.js
  [1005] 2774 - ',' expected.
  [1005] 2789 - ';' expected.