Supabase Auth0 Integration: A Comprehensive Guide

Integrating Supabase with Auth0 can seem like a daunting task, but trust me, guys, it's totally achievable and opens up a world of possibilities for your applications. In this guide, we'll walk through the process step-by-step, ensuring you understand not just how to do it, but why each step is important. Whether you're looking to enhance your app's security, simplify user management, or leverage Auth0's advanced features with Supabase's real-time database capabilities, you're in the right place. So, buckle up, and let's dive into the exciting world of Supabase and Auth0 integration!

Why Integrate Supabase with Auth0?

Before we jump into the how, let's chat about the why. Why would you even want to integrate Supabase with Auth0? Well, there are several compelling reasons. Firstly, enhanced security. Auth0 brings a robust suite of security features, including multi-factor authentication (MFA), anomaly detection, and adaptive authentication. By integrating with Supabase, you can leverage these features to protect your application's data and user accounts. Secondly, simplified user management. Auth0 provides a centralized platform for managing users, roles, and permissions. This can significantly reduce the overhead of managing users directly within Supabase. You can easily create, update, and delete users, assign roles, and configure permissions all from Auth0's intuitive dashboard. Thirdly, social login support. Auth0 supports a wide range of social login providers, such as Google, Facebook, Twitter, and more. This makes it easy for users to sign up and log in to your application using their existing social accounts. Integrating with Supabase allows you to seamlessly integrate these social login options into your Supabase application. Lastly, scalability and reliability. Auth0 is a highly scalable and reliable authentication platform. By offloading authentication to Auth0, you can focus on building your application's core features without worrying about the complexities of managing authentication at scale. This ensures that your application remains responsive and available, even during peak usage periods. Integrating these two platforms offers a best-of-both-worlds scenario: Supabase's powerful database and real-time capabilities combined with Auth0's comprehensive authentication and authorization services. It's a match made in digital heaven!

Prerequisites

Okay, before we get our hands dirty, let's make sure we have all the necessary tools and accounts ready. Think of it as gathering your ingredients before you start cooking. First, you'll need a Supabase account. If you don't already have one, head over to the Supabase website and sign up for a free account. Supabase provides a generous free tier that's perfect for testing and development. Once you have an account, create a new project. This will be the container for your Supabase database and other services. Make note of your Supabase URL and API key, as you'll need these later. Next, you'll need an Auth0 account. Similarly, if you don't have one, sign up for a free Auth0 account. Auth0 also offers a free tier that's suitable for development and small-scale production use. Once you have an account, create a new application. Choose the appropriate application type based on your project (e.g., web application, native application, etc.). Take note of your Auth0 domain, client ID, and client secret, as you'll need these later as well. Finally, you'll need a development environment. This could be your local machine, a virtual machine, or a cloud-based development environment. Make sure you have Node.js and npm (or yarn) installed, as we'll be using these to set up a sample application. With these prerequisites in place, you're ready to start integrating Supabase with Auth0. It's like having all the right ingredients and tools ready to cook up a delicious application!

Setting Up Auth0

Alright, let's dive into setting up Auth0. This is where we'll configure Auth0 to handle authentication for our Supabase application. First, log in to your Auth0 dashboard and navigate to the Applications section. Select the application you created earlier. If you haven't created one yet, now's the time! Click on the Settings tab. Here, you'll find important information about your application, such as your domain, client ID, and client secret. Make a note of these values, as you'll need them later. Next, configure the Allowed Callback URLs. These are the URLs that Auth0 will redirect to after a user successfully authenticates. For development purposes, you can set this to http://localhost:3000/callback (or the appropriate URL for your local development server). In a production environment, you'll need to set this to the actual URL of your application. Also, configure the Allowed Logout URLs. This is the URL that Auth0 will redirect to after a user logs out. Again, for development purposes, you can set this to http://localhost:3000 (or the appropriate URL for your local development server). In a production environment, you'll need to set this to the actual URL of your application. Finally, configure the Allowed Web Origins. This is the URL of your application that is allowed to make requests to Auth0. For development purposes, you can set this to http://localhost:3000 (or the appropriate URL for your local development server). In a production environment, you'll need to set this to the actual URL of your application. Save your changes. Now that you've configured your Auth0 application, let's move on to setting up Supabase.

Setting Up Supabase

Now that Auth0 is configured, let's set up Supabase to work with Auth0. This involves creating a new Supabase project and configuring it to accept authentication tokens from Auth0. First, log in to your Supabase dashboard and create a new project. If you already have a project, you can use that instead. Once your project is created, navigate to the Authentication section in the Supabase dashboard. Here, you'll find various authentication providers that Supabase supports. Since we're using Auth0, we'll need to configure a Custom OAuth Provider. Click on the Add Provider button and select Custom. Now, you'll need to provide the necessary configuration for the custom OAuth provider. This includes the Provider Name, Client ID, Client Secret, Authorize URL, Token URL, and User Info URL. You can obtain these values from your Auth0 application settings. The Provider Name can be anything you want, such as "Auth0". The Client ID and Client Secret are the same as the ones you noted down earlier from your Auth0 application settings. The Authorize URL is typically https://<your-auth0-domain>/authorize. Replace <your-auth0-domain> with your actual Auth0 domain. The Token URL is typically https://<your-auth0-domain>/oauth/token. Replace <your-auth0-domain> with your actual Auth0 domain. The User Info URL is typically https://<your-auth0-domain>/userinfo. Replace <your-auth0-domain> with your actual Auth0 domain. Save your changes. With the custom OAuth provider configured, Supabase is now ready to accept authentication tokens from Auth0. Next, we'll set up a sample application to test the integration.

Building a Sample Application

Okay, let's get our hands dirty with some code! We'll build a simple application that uses Auth0 for authentication and Supabase for data storage. This will help us understand how the two services work together. First, create a new directory for your project and navigate into it using the command line. Initialize a new Node.js project using npm init -y. This will create a package.json file in your project directory. Next, install the necessary dependencies. We'll need the supabase-js library for interacting with Supabase, the auth0-js library for handling Auth0 authentication, and the dotenv library for loading environment variables. Run the following command to install these dependencies: npm install @supabase/supabase-js auth0-js dotenv. Create a new file named .env in your project directory. This file will store your sensitive configuration values, such as your Supabase URL, API key, Auth0 domain, client ID, and client secret. Add the following lines to your .env file, replacing the placeholders with your actual values:

SUPABASE_URL=<your-supabase-url>
SUPABASE_API_KEY=<your-supabase-api-key>
AUTH0_DOMAIN=<your-auth0-domain>
AUTH0_CLIENT_ID=<your-auth0-client-id>

Create a new file named index.html in your project directory. This file will contain the HTML for our sample application. Add the following HTML code to your index.html file:

<!DOCTYPE html>
<html>
<head>
 <title>Supabase Auth0 Integration</title>
</head>
<body>
 <h1>Supabase Auth0 Integration</h1>
 <button id="login-button">Login</button>
 <button id="logout-button">Logout</button>
 <div id="user-info"></div>
 <script src="script.js"></script>
</body>
</html>

Create a new file named script.js in your project directory. This file will contain the JavaScript code for our sample application. Add the following JavaScript code to your script.js file:

require('dotenv').config();
const { createClient } = require('@supabase/supabase-js');
const auth0 = require('auth0-js');

const supabaseUrl = process.env.SUPABASE_URL;
const supabaseApiKey = process.env.SUPABASE_API_KEY;
const auth0Domain = process.env.AUTH0_DOMAIN;
const auth0ClientId = process.env.AUTH0_CLIENT_ID;

const supabase = createClient(supabaseUrl, supabaseApiKey);

const webAuth = new auth0.WebAuth({
 domain: auth0Domain,
 clientID: auth0ClientId,
 redirectUri: 'http://localhost:3000/callback',
 responseType: 'token id_token',
 scope: 'openid profile email'
});

document.getElementById('login-button').addEventListener('click', () => {
 webAuth.authorize();
});

document.getElementById('logout-button').addEventListener('click', () => {
 webAuth.logout({ returnTo: 'http://localhost:3000' });
});

webAuth.parseHash((err, authResult) => {
 if (authResult && authResult.accessToken && authResult.idToken) {
 window.location.hash = '';
 localStorage.setItem('access_token', authResult.accessToken);
 localStorage.setItem('id_token', authResult.idToken);
 displayUserInfo(authResult);
 } else if (err) {
 console.log(err);
 alert(
 'There was an error logging you in: ' + err.error + '. Check the console for more details.'
 );
 }
});

async function displayUserInfo(authResult) {
 const accessToken = localStorage.getItem('access_token');
 const idToken = localStorage.getItem('id_token');

 const { data: user, error } = await supabase.auth.getUser(accessToken);

 if (error) {
 console.error('Error fetching user data from Supabase:', error);
 return;
 }

 document.getElementById('user-info').innerHTML = `
 <p>User ID: ${user.id}</p>
 <p>Email: ${user.email}</p>
 <p>Access Token: ${accessToken}</p>
 <p>ID Token: ${idToken}</p>
 `;
}

This code sets up a basic application with login and logout buttons. When the user clicks the login button, they are redirected to Auth0 to authenticate. After successful authentication, Auth0 redirects the user back to the application with an access token and an ID token. The application then stores these tokens in local storage and displays the user's information. Run npm install dotenv and then start a simple HTTP server to serve your index.html file. You can use a tool like http-server or live-server for this purpose. Open your browser and navigate to http://localhost:3000. You should see the sample application. Click the login button to authenticate with Auth0. After successful authentication, you should see your user information displayed on the page. Congrats, you have successfully integrated Supabase with Auth0!

Securing Supabase Data with Auth0 Roles

Now, let's take our integration a step further and use Auth0 roles to secure our Supabase data. This will allow us to control access to different parts of our application based on the user's role. First, you need to define roles in Auth0. Go to your Auth0 dashboard and navigate to the Users & Roles section. Create a new role, such as "admin" or "editor". Assign users to the appropriate roles. Next, you need to configure Auth0 to include the user's roles in the ID token. Go to your Auth0 dashboard and navigate to the Rules section. Create a new rule that adds the user's roles to the ID token. Here's an example of a rule that does this:

function (user, context, callback) {
 const assignedRoles = (context.authorization || {}).roles;

 context.idToken['https://example.com/roles'] = assignedRoles;

 callback(null, user, context);
}

Replace https://example.com/roles with a namespace for your roles. This namespace should be unique to your application. In your Supabase application, you can now access the user's roles from the ID token. You can use these roles to control access to different parts of your application. For example, you can use the roles to determine whether a user is allowed to create, read, update, or delete data in your Supabase database. To do this, you can use Supabase's Row Level Security (RLS) feature. RLS allows you to define policies that control access to data based on the user's attributes, such as their roles. For example, you can create a policy that allows only users with the "admin" role to update certain tables in your database. By combining Auth0 roles with Supabase RLS, you can create a highly secure and flexible application. This allows you to easily manage user permissions and control access to your data. Remember to always validate user input and sanitize data to prevent security vulnerabilities. With these security measures in place, you can build a robust and secure application using Supabase and Auth0.

Conclusion

Integrating Supabase with Auth0 might have seemed like a mountain to climb, but look at you now – you've conquered it! We've walked through setting up both platforms, building a sample application, and even securing our data using Auth0 roles and Supabase's Row Level Security. This powerful combination allows you to create secure, scalable, and feature-rich applications with ease. Remember, the key to successful integration is understanding the why behind each step. By understanding why we're configuring certain settings or writing specific code, we can better troubleshoot issues and adapt the integration to our specific needs. So, go forth and build amazing things with Supabase and Auth0! The possibilities are endless, and with the knowledge you've gained from this guide, you're well-equipped to tackle any challenge that comes your way. Happy coding, and I can't wait to see what you create!