Authentication and Authorization in Next.js: A Complete Tutorial

Authentication and authorization are two of the most important aspects of developing a secure web application. With Next.js, you can easily setup authentication and authorization for your application with just a few lines of code. In this tutorial, we'll explore how to get started with authentication and authorization in Next.js.

What is Authentication and Authorization?

Authentication is the process of verifying a user's identity. This is usually done by requiring the user to enter a username and password. Once the user is authenticated, authorization is used to determine what resources and actions the user can access.

Getting Started with Authentication and Authorization in Next.js

Next.js provides a few different options for implementing authentication and authorization. The most popular option is to use the next-auth (opens in a new tab) library. Next-auth provides a simple and secure authentication system that can be used with any Next.js application.

To get started with next-auth, first install the library:

npm install next-auth

Once the library is installed, you can create an auth.js file in your project's root directory. This file will contain the configuration for your authentication system. Here is an example of a simple configuration:

// auth.js
const NextAuth = require('next-auth');
const NextAuthConfig = require('./next-auth.config.js');
 
module.exports = (req, res) => NextAuth(req, res, NextAuthConfig);

The next-auth.config.js file will contain the configuration for the authentication system. Here is an example of a simple configuration:

// next-auth.config.js
const providers = [
  {
    name: 'google',
    label: 'Google',
    type: 'oauth',
    version: 2,
    scope: ['profile', 'email'],
    options: {
      clientId: process.env.GOOGLE_CLIENT_ID,
      clientSecret: process.env.GOOGLE_CLIENT_SECRET,
    },
  },
];
 
module.exports = {
  providers,
  database: process.env.DATABASE_URL,
};

This configuration will enable users to sign in with their Google account. You can add additional providers by adding them to the providers array.

Once the configuration is complete, you can start using the authentication system in your application. The easiest way to do this is to use the useAuth hook provided by next-auth. This hook provides access to the user's authentication state and allows you to access protected resources.

Here is an example of how to use the useAuth hook to protect a page:

// pages/protected.js
import { useAuth } from 'next-auth/client';
 
// Page component
export default function ProtectedPage() {
  const [user] = useAuth();
  if (!user) {
    return <p>You must be logged in to view this page.</p>;
  }
  return <p>Welcome {user.name}!</p>;
}

In this example, the useAuth hook is used to check if the user is logged in. If the user is not logged in, they will be prompted to do so. Otherwise, they will be welcomed to the page.

Conclusion

Authentication and authorization are essential for creating secure and robust web applications. Next.js makes it easy to setup authentication and authorization with the next-auth library. In this tutorial, we explored how to get started with authentication and authorization in Next.js.

For more information on authentication and authorization in Next.js, check out the official Next.js docs (opens in a new tab).