Supabase: Email Sign-Ups Made Easy

Oct 23, 2025 by Jhon Lennon 35 views

Hey guys! Ever wondered how to make user sign-ups a breeze in your web or mobile app? Well, you've come to the right place! Today, we're diving deep into Supabase and how you can implement email sign-ups like a pro. We’re going to cover everything from setting up your Supabase project to handling those crucial user verifications. So, buckle up and let’s get started!

Setting Up Your Supabase Project

First things first, you need a Supabase project. If you haven't already, head over to Supabase and create an account. Once you're in, create a new project. Give it a cool name and choose a region that's closest to your users. This will reduce latency and provide a smoother experience for everyone. After your project is set up, grab your API URL and anon key from the project settings. You'll need these to connect your application to Supabase.

Next, let's talk about setting up your authentication. Supabase offers a built-in authentication system that's super easy to use. Go to the Authentication section in your Supabase dashboard and enable the Email provider. This will allow users to sign up with their email addresses and passwords. While you're there, customize the email templates to match your brand. You can tweak the confirmation email, password reset email, and more. Make sure to add your app's name and logo to make it look professional.

Now, let’s dive into the code. Whether you're using JavaScript, React, Vue, or any other framework, Supabase provides client libraries that make integration seamless. Install the Supabase client library for your preferred language. For example, if you're using JavaScript, you can install it via npm or yarn:

npm install @supabase/supabase-js

Or:

yarn add @supabase/supabase-js

Once the library is installed, initialize the Supabase client with your API URL and anon key:

import { createClient } from '@supabase/supabase-js';

const supabaseUrl = 'YOUR_SUPABASE_URL';
const supabaseKey = 'YOUR_SUPABASE_ANON_KEY';
const supabase = createClient(supabaseUrl, supabaseKey);

Replace YOUR_SUPABASE_URL and YOUR_SUPABASE_ANON_KEY with the actual values from your Supabase project. And that's it! Your project is now connected to Supabase, and you're ready to implement email sign-ups.

Implementing Email Sign-Ups

Okay, so you've got your Supabase project all set up. Awesome! Now, let’s get to the good stuff: implementing email sign-ups. We’re going to walk through the code you’ll need to add to your application to allow users to create accounts using their email addresses and passwords. This involves creating a simple form, handling user input, and using the Supabase client library to send the sign-up request.

First, let’s create a basic HTML form with fields for email and password. This form will capture the user's input and trigger the sign-up process when they click the submit button. Here’s what the HTML might look like:

<form id="signup-form">
  <label for="email">Email:</label>
  <input type="email" id="email" name="email" required><br><br>

  <label for="password">Password:</label>
  <input type="password" id="password" name="password" required><br><br>

  <button type="submit">Sign Up</button>
</form>

This form includes labels and input fields for email and password, both marked as required. The submit button will trigger the form submission. Now, let's add some JavaScript to handle the form submission and send the sign-up request to Supabase.

Here’s the JavaScript code you’ll need to handle the form submission and use the Supabase client to sign up the user:

const form = document.getElementById('signup-form');

form.addEventListener('submit', async (e) => {
  e.preventDefault();

  const email = document.getElementById('email').value;
  const password = document.getElementById('password').value;

  const { data, error } = await supabase.auth.signUp({
    email: email,
    password: password,
  });

  if (error) {
    console.error('Sign-up error:', error.message);
    alert('Failed to sign up: ' + error.message);
  } else {
    console.log('Sign-up success:', data);
    alert('Sign-up successful! Check your email to verify your account.');
  }
});

In this code, we’re attaching an event listener to the form that listens for the submit event. When the form is submitted, we prevent the default form submission behavior using e.preventDefault(). Then, we grab the email and password values from the input fields. We use the supabase.auth.signUp method to send the sign-up request to Supabase. This method takes an object with the email and password as parameters.

The signUp method returns a promise that resolves with either a data object or an error object. If there’s an error, we log it to the console and display an alert to the user. If the sign-up is successful, we log the data to the console and display a success message to the user, informing them to check their email to verify their account.

And that’s it! With this code, users can now sign up with their email addresses and passwords. Supabase will handle the rest, including sending a confirmation email to verify their account.

Handling User Verification

Alright, so you've got users signing up left and right. That's fantastic! But, there's one more crucial step: user verification. You want to make sure those email addresses are legit, right? Supabase makes this super easy with its built-in email confirmation feature. When a user signs up, Supabase automatically sends them a verification email. Let's see how to handle this properly.

First, you need to configure your email settings in Supabase. Go to the Authentication section in your Supabase dashboard, and then click on Email Templates. Here, you can customize the confirmation email that Supabase sends to new users. Make sure the email includes a clear call to action, like a button or a link, that users can click to verify their account. Customize the email to match your brand, and include a friendly message to encourage users to verify their email address.

Next, let’s talk about redirecting users after they click the verification link. By default, Supabase redirects users to a generic success page. But, you probably want to redirect them to a specific page in your application, like their profile page or a dashboard. To do this, you need to configure the redirect_to parameter in your Supabase project settings. Set the redirect_to URL to the page you want users to be redirected to after they verify their email address.

Now, let’s handle the user verification in your application. When a user clicks the verification link, Supabase will automatically update their user record in the database, setting the email_confirmed_at field to the current timestamp. This indicates that the user's email address has been verified. In your application, you can check this field to determine whether a user has verified their email address. If they haven't, you can prompt them to verify their email address before allowing them to access certain features.

Here’s how you can check if a user has verified their email address in your application:

const user = supabase.auth.user();

if (user && user.email_confirmed_at) {
  // User has verified their email address
  console.log('User is verified!');
} else {
  // User has not verified their email address
  console.log('User is not verified!');
  // Prompt the user to verify their email address
}

In this code, we’re using the supabase.auth.user() method to get the current user object. We then check if the email_confirmed_at field is set. If it is, the user has verified their email address. If it’s not, the user has not verified their email address, and you can prompt them to do so.

You can also use Supabase’s Realtime subscriptions to listen for changes to the email_confirmed_at field. This allows you to update your UI in real-time when a user verifies their email address. For example, you can display a success message or redirect the user to a different page.

Securing Your Sign-Up Process

Okay, we've got sign-ups and verifications down. But hold on, security is super important! We need to make sure our sign-up process is as secure as possible to protect our users and our application. Let’s talk about some key security measures you should implement.

First, let’s talk about password policies. Enforcing strong password policies is crucial to prevent users from choosing weak or easily guessable passwords. Supabase doesn't enforce password policies out of the box, so you’ll need to implement them in your application. Require users to choose passwords that are at least 8 characters long, and include a mix of uppercase letters, lowercase letters, numbers, and symbols. You can use a regular expression to validate the password before submitting it to Supabase.

Here’s an example of how you can validate a password using a regular expression:

function validatePassword(password) {
  const regex = /^(?=.*[a-z])(?=.*[A-Z])(?=.*\d)(?=.*[!@#$%^&*()_+{}${}$:;<>,.?~\-]).{8,}$/;
  return regex.test(password);
}

const password = document.getElementById('password').value;

if (!validatePassword(password)) {
  alert('Password must be at least 8 characters long and include uppercase letters, lowercase letters, numbers, and symbols.');
  return;
}

In this code, we’re using a regular expression to check if the password meets the following criteria:

At least 8 characters long
Includes at least one uppercase letter
Includes at least one lowercase letter
Includes at least one number
Includes at least one symbol

If the password doesn’t meet these criteria, we display an alert to the user and prevent the form from submitting.

Next, let’s talk about rate limiting. Rate limiting is a technique used to limit the number of requests a user can make to your application within a certain time period. This helps prevent abuse and protects your application from denial-of-service attacks. Supabase doesn't provide built-in rate limiting, so you’ll need to implement it yourself. You can use a middleware or a library to implement rate limiting in your application.

Here’s an example of how you can implement rate limiting using the express-rate-limit middleware in a Node.js application:

const rateLimit = require('express-rate-limit');
const app = express();

const limiter = rateLimit({
  windowMs: 15 * 60 * 1000, // 15 minutes
  max: 100, // Limit each IP to 100 requests per windowMs
  message:
    'Too many requests from this IP, please try again after 15 minutes',
});

// Apply the rate limiting middleware to all requests
app.use(limiter);

In this code, we’re using the express-rate-limit middleware to limit each IP address to 100 requests per 15 minutes. If an IP address exceeds this limit, the middleware will return a 429 status code with a message indicating that the user has made too many requests.

Another important security measure is to protect against cross-site scripting (XSS) attacks. XSS attacks occur when an attacker injects malicious code into your application, which is then executed by other users. To prevent XSS attacks, you should always sanitize user input before displaying it in your application. This involves removing or escaping any potentially malicious code.

Wrapping Up

So there you have it! You've learned how to set up Supabase, implement email sign-ups, handle user verification, and secure your sign-up process. With these steps, you're well on your way to creating a smooth and secure user experience in your application. Keep experimenting, keep learning, and have fun building awesome things with Supabase!