MetaMask Authentication via Backend API Calls: A Feasibility Study

As a web application developer, integrating user authentication with external services like MetaMask is becoming increasingly popular. However, currently, transactions are authenticated by MetaMask when interacting with their browser extension. But is it possible to perform the same user steps via backend calls instead? In this article, we will explore the feasibility of MetaMask authentication via backend API calls.

Current Workflow

When users interact with a web application that uses MetaMask, their browser extension sends an authorization request to MetaMask on behalf of the user. This request includes sensitive data such as the user’s wallet address and passphrase. MetaMask then validates this information and allows the user to proceed with the transaction.

Proposed Solution

To facilitate authentication via backend API calls, we would need to implement the following:

• Backend API: Develop an API that can be integrated into our web application to manage user authentication.

• MetaMask Integration: Integrate the MetaMask API to authenticate users and perform transactions on their behalf.

• API Calls: Make API calls from our backend to initiate a transaction.

Technical Challenges

Before we start the implementation, we need to consider several technical challenges:

• Authentication Protocols: We should implement authentication protocols like OAuth or OpenID Connect to securely authenticate users.

• Transaction Validation: Our backend API should validate and execute transactions on behalf of MetaMask, ensuring that the transaction is valid and secure.

• Scalability: As our application grows in popularity, we would need to provide scalability to handle increased traffic.

Feasibility study

To evaluate the feasibility of authenticating Metamask via background API calls, let’s consider a hypothetical example:

Suppose our web application allows users to connect their MetaMask wallets and make transactions. We would develop an API that accepts user input (eg transaction details) and sends it to MetaMask for verification.

Backend API Implementation

Here’s an outline of the proposed implementation of the backend API:

Node.js API endpoint

app.post('/auth', (req, res) => {

  const { address, secret } = req.body;

  // Verify the user's wallet address and passphrase with MetaMask

  if (!verifyWallet(address)) return res.status(401).send('Invalid wallet address');

  if (!verifySecret(secret)) return res.status(401).send('Invalid secret phrase');

  

  // Perform the transaction using the MetaMask API

  const { txHash, nonce } = authenticateTransaction(address);

  // Send transaction details to MetaMask for verification

  metaMask.sendVerificationTx(txHash, nonce)

    .then((response) => {

      res.json({ success: true });

    })

    .catch((error) => {

      console.error(error);

      res.status(500).send('Error confirming transaction');

    });

});

MetaMask integration

To integrate the MetaMask API, we should:

• Get user’s passphrase: Get user’s passphrase from their MetaMask wallet.

• Get User’s Wallet Address: Get the user’s wallet address from their MetaMask wallet.

Once we have these values, we can use them to authenticate a transaction using the MetaMask API.

Conclusion

While integrating Metamask authentication via backend API calls is technically feasible, it poses several technical challenges that need to be addressed. In order to overcome these challenges, a thorough feasibility study and implementation would be required. Additionally, scalability and security issues need to be considered at every stage of the development process.