Integrating Auth0 with a Next.js Application

Objectives

Learn how Auth0 authorization works and implement it in a demo Next.js project.

Authorization Code Flow

Before the demo, we need to know how authorization code flow works in a web application integrated with Auth0.

Let's walk through the steps provided by Auth0

  1. User selects Login within application.
  2. Auth0's SDK redirects user to Auth0 Authorization Server ( /authorize endpoint).
  3. Auth0 Authorization Server redirects user to login and authorization prompt.
  4. User authenticates using one of the configured login options, and may see a consent prompt listing the permissions Auth0 will give to the application.
  5. Auth0 Authorization Server redirects user back to application with single-use authorization code.
  6. Auth0's SDK sends authorization code, application's client ID, and application's credentials, such as client secret or Private Key JWT, to Auth0 Authorization Server ( /oauth/token endpoint).
  7. Auth0 Authorization Server verifies authorization code, application's client ID, and application's credentials.
  8. Auth0 Authorization Server responds with an ID token and access token (and optionally, a refresh token)
  9. Application can use the access token to call an API to access information about the user.
  10. API responds with requested data.

Demo

Sign Up

Sign up auth0 and create an account.

Create an application (Next.js)

Download the starter project here.

Install all the dependecies using npm install.

Configure Callback URLs

A callback URL is a URL in your application where Auth0 redirects the user after they have authenticated. You should add it in your project settings.

Configure Logout URLs

A logout URL is a URL in your application that Auth0 can return to after the user has been logged out of the authorization server. You should add it in your project settings too.

Install the Auth0 Next.js SDK

npm install @auth0/nextjs-auth0

Add credentials

Swap these fields with your information in .env.local.

You should see your information in the project settings. The project setting page should look similar to this:

Run the app

Notice that this next.js starter project handles most of the SDK configuration. Feel free to checkout the auth0 documentation for more information about the SDK. Now, you can run the app using: 

npm run dev

You can see the app hosting on port 3000.

When you press the login button, it will take you to the login page. And you can login with your account. After a successful login, you will be redirected to the home page. You can see your profile on the top right corner. That's it! You have successfully integrated a Next.js application with Auth0.

Conclusion

In conclusion, Auth0 simplifies the process of adding authentication and identity management to web applications. It also offers easy-to-use SDKs, libraries, and plugins for various programming languages and frameworks. In this post, I have demonstrated how to integrate Auth0 with a Next.js application. I hope you find this post helpful. Thank you for reading! 😊

Source