MetaMask API – Build a Web App User Sign-up and Login
The cryptocurrency wallet is the main touchpoint connecting prospects and customers in the Web3 app. Furthermore, it’s a trending fashionable approach to appeal to new signups and convert more sales.
In this article, I would briefly walk through how to let new users sign up for an account on your web app using Metamask API. By the end of this article, your visitors can sign up using the MetaMask wallet and you can identify the users using the wallet public key.
The cryptocurrency wallet is the main touchpoint connecting prospects and customers in the Web3 app. Furthermore, it’s a trending fashionable approach to appeal to new signups and convert more sales.
In this article, I would briefly walk through how to let new users sign up for an account on your web app using Metamask API. By the end of this article, your visitors can sign up using the MetaMask wallet and you can identify the users using the wallet public key.
Table of Contents: Web App New User Sign-up, Login Using Metamask API, Javascript
- MetaMask Javascript Code in Frontend
- Flask Route Code in Backend to Store the Public Key
- Full Javascript and Python Script of User Sign-up and Login System
- FAQ
MetaMask Javascript Code in Frontend
First thing first, it requires developers to add the Ethereum provider detector script between the header
<script src="https://cdn.jsdelivr.net/npm/@metamask/detect-provider"></script>
Then, we need to write a Javascript to trigger the Metamask account access request when the user clicks the signup or login button.
<section>
<form action="/login" method="GET" onsubmit="return false;">
<button id="connect-button" type="button">Connect with MetaMask</button>
</form>
</section>
<script>
const connectButton = document.querySelector('#connect-button');
In this case, there are two scenarios. MetaMask extension has been installed or not on the browser. Therefore, we need to add an if condition in this click event.
connectButton.addEventListener('click', async () => {
// Check if MetaMask is installed
if (typeof window.ethereum === 'undefined') {
alert('Please install MetaMask to continue.');
Return;
}
The next step requires us to call the MetaMask and grab the account address for creating a new User ID in a database or identify whom when the user logins in.
const accounts = await window.ethereum.request({ method: 'eth_requestAccounts' });
const metamaskAddress = accounts[0];
Last but not least, we will send the account public key to the web app database. As MetaMask uses the args.get parameter. So here is the code sample as follows:
window.location.href = '/login?metamask_address=' + metamaskAddress;
} catch (error) {
console.error(error);
Flask Route Code in Backend to Store the Public Key
Once the user confirms to connect with your Web App, her or his wallet public key would respond to your app server. Here is the code sample to capture the key for user authentication from now on.
@app.route('/login', methods=['GET', 'POST'])
def login():
metamask_address = request.args.get('metamask_address')
return render_template('masklogin.html', metamask_address=metamask_address)
Regarding the new user database setup, here are two articles in which one elaborates on using SQL and the other explains MongoDB. For more details, please check out.
https://www.easy2digital.com/automation/data/python-tutorial-66-flask-application-database-using-mongodb-atlas-and-python-to-better-big-data-management/
Full Javascript and Python Script of User Sign-up and Login System
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FAQ:
Q1: What is Metamask?
A: Metamask is a software cryptocurrency wallet used to interact with the Ethereum blockchain. It allows users to store and manage their Ethereum and other ERC-20 tokens, and to interact with decentralized applications (dApps).
Q2: What is the Metamask API?
A: The Metamask API is a set of endpoints that allow developers to interact with the Metamask wallet. This includes the ability to get account information, send transactions, and sign messages.
Q3: How can I use the Metamask API for user login?
A: You can use the Metamask API to allow users to login to your dApp using their Metamask wallet. This can be done by using the `eth_requestAccounts` method to get the user’s public key, and then using the `eth_sign` method to sign a message with the user’s private key.
Q4: What are the benefits of using the Metamask API for user login?
A: There are several benefits to using the Metamask API for user login. First, it is a very secure way to login, as the user’s private key is never exposed to your dApp. Second, it is a very convenient way to login, as users only need to have the Metamask extension installed in their browser.
Q5: Are there any risks associated with using the Metamask API for user login?
A: There are a few risks associated with using the Metamask API for user login. First, if the user’s Metamask wallet is compromised, then their private key could be exposed, which could lead to their funds being stolen. Second, if the Metamask API is compromised, then it could be possible for attackers to gain access to users’ private keys.
Q6: How can I mitigate the risks associated with using the Metamask API for user login?
A: There are a few things you can do to mitigate the risks associated with using the Metamask API for user login. First, you should make sure that your dApp is using the latest version of the Metamask API. Second, you should make sure that your dApp is using a secure connection (HTTPS). Third, you should educate your users about the risks of using Metamask and how to protect their private keys.
Q7: What are some alternatives to using the Metamask API for user login?
A: There are a few alternatives to using the Metamask API for user login. One alternative is to use a different cryptocurrency wallet that supports user login, such as Coinbase Wallet or Trust Wallet. Another alternative is to use a centralized login system, such as Google or Facebook.
Q8: Which alternative is the most secure?
A: The most secure alternative to using the Metamask API for user login is to use a different cryptocurrency wallet that supports user login, such as Coinbase Wallet or Trust Wallet. These wallets use a different security model than Metamask, which makes them less vulnerable to attack.
Q9: Which alternative is the most convenient?
A: The most convenient alternative to using the Metamask API for user login is to use a centralized login system, such as Google or Facebook. These systems are very easy to use, as users only need to enter their username and password.
Q10: Which alternative is the best for my dApp?
A: The best alternative for your dApp depends on your specific needs and requirements. If you are looking for a secure and convenient way to allow users to login to your dApp, then you should use a different cryptocurrency wallet that supports user login, such as Coinbase Wallet or Trust Wallet. If you are looking for a very secure way to allow users to login to your dApp, then you should use a centralized login system, such as Google or Facebook.
