Auth.js (formerly NextAuth.js) is the leading open-source authentication framework designed for modern web applications, particularly those built with Next.js. This powerful authentication library simplifies the complex process of implementing secure user login, session management, and OAuth integration while maintaining enterprise-grade security standards.
Whether you're building a startup MVP with Bolt.new or scaling an enterprise application on Vercel, Auth.js provides the authentication infrastructure you need without the complexity of building it from scratch.
Auth.js eliminates the headache of managing multiple authentication providers by offering 50+ built-in OAuth integrations with a consistent configuration pattern. Implement social login with Google, GitHub, Facebook, Apple, LinkedIn, Twitter, and countless other providers using the same simple API.
Unlike custom authentication implementations that require hours of documentation reading for each provider, Auth.js abstracts away provider inconsistencies, automatically handles token renewal and re-authentication when credentials expire, and provides a unified interface regardless of the identity provider you choose.
Security is paramount in authentication systems, and Auth.js delivers production-ready protection through multiple layers:
The library follows OAuth 2.0 and OpenID Connect specifications rigorously, ensuring your authentication flow meets international security standards. Auth.js has been battle-tested in production by thousands of applications and receives regular security audits from the open-source community.
Auth.js offers two powerful session management approaches to match your application architecture:
JWT sessions store user data in encrypted tokens within HttpOnly cookies, eliminating the need for database queries on every request. This serverless-friendly approach delivers exceptional performance, reduces infrastructure costs, and scales effortlessly across edge networks.
Perfect for applications deployed on Vercel edge functions or AWS Lambda, JWT sessions provide sub-millisecond authentication checks without database round trips. Auth.js implements automatic session token rotation and keep-alive mechanisms to maintain security while preserving user experience.
For applications requiring real-time session control, database sessions store only a session identifier in cookies while maintaining full session data in your database. This strategy enables powerful features like:
Database sessions integrate seamlessly with PostgreSQL, MySQL, MongoDB, and SQLite through Auth.js adapter system.
Auth.js supports virtually any database through its comprehensive adapter architecture. Official adapters include:
| Database | Adapter | Use Case |
|---|---|---|
| Prisma | @auth/prisma-adapter | Type-safe ORM supporting PostgreSQL, MySQL, SQLite, MongoDB |
| PostgreSQL | @auth/pg-adapter | Direct PostgreSQL connections for high-performance applications |
| MongoDB | @auth/mongodb-adapter | NoSQL flexibility with schema-less document storage |
| MySQL | @auth/mysql-adapter | Traditional relational database deployments |
| Supabase | @auth/supabase-adapter | Supabase backend-as-a-service integration |
The Prisma adapter is particularly popular for Next.js applications, providing full TypeScript support, automatic migrations, and seamless integration with modern development workflows.
Implementing authentication with Auth.js is remarkably straightforward compared to building custom solutions:
next-auth to your Next.js project via npm or yarn/api/auth/[...nextauth] to handle authentication requestsAUTH_SECRET and provider credentials in your .env fileThe entire setup can be completed in under 30 minutes for basic OAuth authentication, with pre-built sign-in pages included by default. Advanced customization options allow you to tailor every aspect of the authentication experience to match your brand.
While Auth.js originated as NextAuth.js for Next.js applications, version 5 introduced framework-agnostic core functionality through the @auth/core package. This architectural evolution enables Auth.js to power authentication in:
Regardless of your chosen framework, Auth.js provides the same robust authentication features, security guarantees, and developer experience.
Auth.js is built with TypeScript and provides comprehensive type definitions out of the box. Enjoy full IntelliSense support, compile-time type checking for your authentication configuration, and type-safe session access throughout your application.
While Auth.js includes beautifully designed default sign-in pages, you maintain complete control over the authentication interface. Customize built-in pages with your brand colors and logo, or build entirely custom authentication flows using Auth.js headless API.
Implement passwordless authentication using email-based magic links. Auth.js supports email providers like Resend, SendGrid, Nodemailer, and Forward Email, handling token generation, expiration, and verification automatically.
Beyond OAuth and magic links, Auth.js supports traditional username/password authentication with complete flexibility. Integrate with existing user databases, implement custom password hashing strategies, or connect to external authentication APIs.
Auth.js integrates seamlessly with modern backend-as-a-service platforms like Supabase, providing real-time database syncing, automatic user management, and built-in storage for authentication data. Deploy your authenticated application to Vercel with zero-configuration serverless functions that scale automatically.
The combination of Auth.js + Supabase + Vercel creates a powerful full-stack authentication solution that rivals enterprise identity platforms while maintaining complete ownership of your user data.
With over 15,000 GitHub stars and thousands of production deployments, Auth.js has become the de facto authentication standard for Next.js applications. The active open-source community continuously contributes new providers, adapters, and security improvements.
Auth.js follows responsible disclosure practices and aims to respond to security issues within 72 hours, ensuring your authentication infrastructure remains secure against emerging threats.
Auth.js excels for:
While Auth.js provides exceptional flexibility and security, complex enterprise requirements like advanced RBAC (Role-Based Access Control) or custom claims management may benefit from specialized identity platforms. However, for the vast majority of modern web applications, Auth.js delivers the perfect balance of power, simplicity, and security.
If you're currently using NextAuth.js, the transition to Auth.js v5 introduces breaking changes that improve OAuth/OIDC compliance and security. The migration guide on authjs.dev provides step-by-step instructions for updating your configuration, handling deprecated OAuth 1.0 providers, and leveraging new features.
Start building secure, scalable authentication for your Next.js application today with Auth.js—the authentication library trusted by thousands of developers worldwide.
Auth.js is the new name for NextAuth.js, representing the evolution of the authentication library beyond Next.js-only support. Version 5 introduced framework-agnostic core functionality through @auth/core, enabling authentication for Next.js, SvelteKit, SolidStart, Express, and other frameworks. While NextAuth.js focused exclusively on Next.js, Auth.js maintains Next.js as first-class support while expanding to other JavaScript frameworks. The core authentication features, security guarantees, and OAuth provider support remain the same, with improved OAuth/OIDC spec compliance and enhanced flexibility.
Auth.js supports over 50 built-in OAuth providers including Google, GitHub, Facebook, Apple, LinkedIn, Twitter, Microsoft, Discord, Spotify, and many more. All providers use a consistent configuration pattern, making it easy to add multiple social login options without learning different APIs for each provider. Auth.js automatically handles provider-specific quirks, token renewal, and re-authentication. You can also create custom OAuth providers for proprietary identity systems or services not included in the default provider list.
Yes, Auth.js supports database integration through its adapter system. Official adapters include Prisma (supporting PostgreSQL, MySQL, SQLite, MongoDB), PostgreSQL adapter for direct connections, MongoDB adapter for NoSQL flexibility, MySQL adapter, Supabase adapter, and many others. Database integration is optional—Auth.js defaults to JWT-based sessions stored in cookies without requiring a database. Database sessions enable features like instant session revocation, sign out everywhere functionality, and concurrent session limiting. The Prisma adapter is particularly popular for Next.js applications due to its TypeScript support and automatic migrations.
Yes, Auth.js is completely free and open source under the ISC license. You can use it in personal projects, commercial applications, and enterprise deployments without any licensing fees. The project has over 15,000 GitHub stars and is maintained by an active open-source community. While Auth.js itself is free, you may incur costs for third-party services like OAuth provider API usage, email delivery for magic links (Resend, SendGrid), or database hosting for session storage. However, the Auth.js library itself requires no subscription or payment.
Auth.js implements enterprise-grade security features including built-in CSRF protection, JWT encryption with secure token rotation, HttpOnly cookies to prevent XSS attacks, automatic session refresh mechanisms, and strict OAuth 2.0 and OpenID Connect compliance. The library has been battle-tested by thousands of production applications and receives regular security audits from the open-source community. Auth.js follows responsible disclosure practices and responds to serious security issues within 72 hours. Session tokens are encrypted with a secret key, and even if stolen, cannot be decrypted without server access. For maximum security, Auth.js recommends database sessions over JWT for applications requiring real-time revocation capabilities.
Absolutely. Auth.js is designed specifically for serverless deployments and works seamlessly with Vercel, AWS Lambda, Cloudflare Workers, and other serverless platforms. The default JWT-based session strategy eliminates database queries on every request, making it perfect for edge functions and serverless environments. Auth.js handles the challenges of serverless authentication including stateless session management, edge runtime compatibility, and automatic scaling. Deploy your Next.js application with Auth.js to Vercel with zero configuration—the platform automatically detects and optimizes your authentication routes for edge networks.
JWT sessions store encrypted user data directly in HttpOnly cookies, eliminating database queries for authentication checks. This serverless-friendly approach delivers exceptional performance and scales effortlessly. Database sessions store only a session ID in cookies while maintaining full session data in your database, enabling features like instant session revocation, sign out everywhere, concurrent session limiting, and real-time monitoring. Choose JWT sessions for serverless deployments prioritizing speed and simplicity. Choose database sessions when you need real-time session control, revocation capabilities, or advanced session analytics. Auth.js supports both strategies with simple configuration changes.
Getting started with Auth.js takes less than 30 minutes. First, install next-auth via npm or yarn. Second, create an API route at /api/auth/[...nextauth] to handle authentication requests. Third, configure your chosen providers (Google, GitHub, etc.) and add their client IDs and secrets to your .env file. Fourth, set the required AUTH_SECRET environment variable for token encryption. Fifth, protect your pages using built-in middleware or session checks. Auth.js includes pre-built sign-in pages by default, so you can start authenticating users immediately. The official documentation at authjs.dev provides step-by-step guides for OAuth setup, database integration with Prisma, custom authentication flows, and framework-specific implementations.
Supabase is the open-source Firebase alternative built on PostgreSQL. Get instant APIs, real-time subscriptions, authentication, storage, and Edge Functions with the freedom to self-host.
MongoDB is a flexible NoSQL document database with horizontal scaling, real-time analytics, and cloud-native architecture. Perfect for modern applications requiring schema flexibility and massive scale.
Next.js SaaS boilerplate by Marc Lou. Ship startups in days with pre-built authentication, Stripe payments, email integration, and AI-friendly code. Used by 7,754+ makers.