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02 — Auth.js (NextAuth.js)

02 — Auth.js (NextAuth.js)

Section titled “02 — Auth.js (NextAuth.js)”

Introduction

Section titled “Introduction”

Auth.js (formerly NextAuth.js) is a complete open-source authentication solution for Next.js applications. It provides a flexible, secure, and easy-to-use authentication system that supports various providers (OAuth, email, credentials) and adapters (databases).

Why we need Auth.js

Section titled “Why we need Auth.js”

Building authentication from scratch is complex and error-prone. Auth.js handles the intricate details of session management, token handling, CSRF protection, and provider integrations, allowing developers to focus on building features rather than reinventing authentication.

Learning objectives

Section titled “Learning objectives”
  • Understand how Auth.js integrates with Next.js
  • Configure authentication providers (Credentials, Google, GitHub, etc.)
  • Set up database adapters (Prisma, MongoDB, etc.)
  • Customize callbacks, session, and JWT behavior
  • Implement production-ready authentication with security best practices

Prerequisites

Section titled “Prerequisites”
  • Basic understanding of Next.js App Router
  • Familiarity with React and TypeScript/JavaScript
  • Knowledge of OAuth 2.0 and OpenID Connect concepts
  • Node.js >=18 installed

Topics covered

Section titled “Topics covered”
  1. Introduction to Auth.js
  2. Installation and setup
  3. Configuring providers
  4. Credentials provider (email/password)
  5. OAuth providers (Google, GitHub)
  6. Session management
  7. Callbacks and events
  8. Adapters (database integration)
  9. Production setup and deployment

Authentication roadmap with Auth.js

Section titled “Authentication roadmap with Auth.js”
Setup → Providers → Callbacks → Adapter → Customization → Production

Real-world applications

Section titled “Real-world applications”
  • SaaS applications with multi-tenancy
  • E-commerce platforms with user accounts
  • Content management systems with role-based access
  • Internal tools requiring SSO via SAML or LDAP
  • Mobile backends using JWT API routes

Estimated learning time

Section titled “Estimated learning time”

8-12 hours including hands-on exercises

Practice exercises

Section titled “Practice exercises”
  • Set up Auth.js with Credentials provider
  • Add Google and GitHub OAuth providers
  • Connect to PostgreSQL using Prisma adapter
  • Customize session and JWT callbacks
  • Implement role-based access control
  • Deploy to Vercel with environment variables

Mini project

Section titled “Mini project”

Build a full-stack blog platform with:

  • User authentication (email/password + social login)
  • Role-based access (admin, editor, viewer)
  • Protected API routes for creating/editing posts
  • User profile management
  • Email verification (using Email provider)
  • Password reset functionality
Section titled “Related modules”
  • 03-login-registration: Building custom auth flows
  • 04-authorization: Role-based and permission-based access
  • 05-security: Advanced security practices (CSRF, XSS, etc.)
  • 06-third-party-auth: Alternative auth providers (Clerk, Supabase, Firebase)
  • 07-production-auth: Scaling, monitoring, and enterprise patterns