Metamask: Using Ethersjs to Connect Metamask to Local Hardhat Node Provider

Here is an article on using Ethers.js to connect Metamask to a local hardhat node provider:

Connecting Metamask to a Local Hardhat Node Provider with Ethers.js

When developing decentralized applications (dApps) that require interaction with external services such as MetaMask or Web3 providers, it is essential to connect them to a local hardhat node. In this article, we will explore how to use Ethers.js to achieve this connection.

Why use Ethers.js?

Ethers.js is the official JavaScript library for interacting with the Ethereum blockchain. It provides a simple and intuitive API for working with Web3 providers such as MetaMask, Web3.js, and others. Using Ethers.js, you can easily connect your local hardhat node to external services without having to worry about setting up additional infrastructure or configuration.

Setting up your local hardhat node

Before we dive into connecting Metamask, make sure your local hardhat node is set up correctly. Here’s a quick overview of the steps:

• Install the truffle framework: Truffle provides a way to manage and interact with your blockchain projects via JavaScript.

• Set up a new project directory and initialize it:

mkdir metamask-connection-example
cd metamask-connection-example
npx truffle init

• Create a new contract file (e.g., MyContract.sol) inside the project directory:

pragma solidity ^0.8.0;
contract MyContract {
uint256 public value;
}

• Compile and deploy your contract:

truffle compile
truffle deploy

Connecting Metamask with Ethers.js

Now that you have a local hardhat node set up, let’s connect Metamask using Ethers.js. We will use the ethers.js library to interact with MetaMask.

Create a new file called metamask-connection.js and add the following code:

const ethers = require('ethers');
// Set the contract address and ABI
const contractAddress = '0x...'; // Replace with your contract address
const abi = [...]; // Replace with your contract ABI
// Create a new Ethers provider instance for your local hardhat node
const provider = new ethers.providers.HttpProvider('
// Create a new Ethers.js wallet instance using MetaMask provider
const wallet = new ethers.Wallet(provider, '0x...'); // Replace with your MetaMask private key
// Get the contract instance using the wallet
const contractInstance = new ethers.Contract(contractAddress, abi, wallet);
// Now you can use the contract instance to interact with the blockchain
contractInstance.value.set(123);

Example Usage

Here is an example of how you can use the Metamask connection to set a value on your contract:

metamask-connection.js

Assuming you have a MyContract.sol file in the same directory, you can call the following function to update the contract instance:

setValue = (value) => {
contractInstance.value.set(value);
}

Tips and Variations

• Make sure to replace the contractAddress, abi and wallet variables with your actual contract address, ABI and MetaMask private key.

• You can also use other Ethers.js providers like or

• If you are using a different Web3 provider (e.g. Web3.js), you will need to modify your connection code accordingly.

By following these steps and examples, you should now be able to connect your local hardhat node to Metamask with Ethers.js. Happy building!

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