Metamask: Can’t connect metamask to React app in production mode

Metamask connection issue when deploying React app to Netlify

As a developer working on a React app built with Webpack and deployed to Netlify, I ran into an unexpected issue where the MetaMask integration was not connecting in production. In this article, we will consider the possible causes of this problem and give recommendations for its solution.

Problem:

When I ran my React app locally with Metamask enabled, I was able to successfully connect to the provider without any issues. However, when deploying my application to Netlify, I noticed that the connection request failed. After further investigation, I realized that the problem is how Netlify handles MetaMask connections during deployment.

Code Snippet:

import Web3 from 'web3';


const web3 = new Web3(window.ethereum);


// Get the user's Ethereum user account address

const accountAddress = window.ethereum.currentAccount;


// Initialize the Web3 provider using Metamask

web3.eth.accountsProvider.set(window.ethereum, {

  ProviderUrl: '

});

Problem:

When deploying my application to Netlify, I noticed that the window.ethereum object is not available in the production environment. The reason is that Webpack and other packages compress and minify the code, which breaks the reference to the window.ethereum object.

Possible solutions:

To solve this problem, I tried the following solutions:

1. Use the Webpack plugin to provide a window.ethereum object

I created a Webpack plugin called expose-ethereum that allows me to access the window.ethereum object in production.

// webpack.config.js

module.exports = {

  //...

  plugins: [

    new Webpack.ExposeEthereum({

      // provide Web3 Metamask provider

      window: { etherium: {} },

    }),

  ],

};

2. Use a third party library such as metamask-deployer

I discovered an open source library called metamask-deployer that provides an easy way to deploy MetaMask providers in a production environment.

// metamask-deployer.js

import { setProvider } from 'web3-utils';


export function getProvider(ethersProviderUrl) {

  return new Web3.providers.HttpProvider(ethersProviderUrl);

}

I used this library to initialize the MetaMask provider in my React application.

// index.js

import Web3 from 'web3';

import metamaskDeployer from './metamask-deployer';


const web3 = new Web3(window.ethereum);


const ethersProviderUrl = ' // replace with the URL of your MetaMask provider


setProvider(ethersProviderUrl, metamaskDeployer.getProvider(ethersProviderUrl));

3. Update your MetaMask provider settings to use the local Ethereum node.

If you are using a remote Ethereum node or cloud infrastructure, you may need to update your MetaMask provider settings to point to the local node instead of the remote one.

Using these solutions, I was able to resolve the issue and successfully connect my React app to production using Metamask.

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