Preparing the Recipient Contract

We will be using Remix web IDE to compile and deploy Smart Contracts to the Blockchain.

Recipient Smart Contracts that are supposed to be called via Meta Transactions need to inherit from ERC2771Context which provides a mechanism to override the sender and calldata of the execution context (msg.sender and msg.data) with custom values specified by a trusted forwarder.

Remix IDE

• Create a new file in Remix and name it Counter.

• For demo purposes we will be using a simple counter contract.

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

import "@openzeppelin/contracts/metatx/ERC2771Context.sol";

contract Counter is ERC2771Context {
    uint256 private count = 0; // A variable to hold the value of the counter

    constructor(address trustedForwarder) ERC2771Context(trustedForwarder) {
    }

    // Function to increase the counter by 1
    function incrementCounter() public {
        count += 1;
    }

    // Function to read the current value of the counter
    function getCount() public view returns (uint256) {
        return count;
    }
}

• As shown in the code snippet, we imported ERC2771Context.sol from OpenZeppelin 1.

• This contract inherits from ERC2771Context 2.

• We added a constructor for the contract that passes the trusted forwarder to the constructor of ERC2771Context 3.

• Then compile the file using compiler version 0.8.20+. After that you go to DEPLOY & RUN TRANSACTIONS tab and select from the Environment drop down Injected Provider - MetaMask 4.

• Make sure the correct contract is selected in the Contract drop down which is Counter 5.

• Lastly you need to provide the Trusted Forwarder Address that we deployed earlier to the Counter constructor in order to deploy this contract 6.