NextAuth.js is an open-source authentication library for Next.js applications. It simplifies the implementation of various authentication methods, including OAuth, JWT, and providers like Google, Facebook, and GitHub. With a straightforward configuration, developers can seamlessly add user authentication to their projects, whether it’s server-side rendered, static, or client-side rendered. NextAuth.js ensures secure authentication and session management while supporting multiple authentication flows. It also offers built-in support for email-based magic links and password less logins. By handling complex authentication processes and providing a unified interface, NextAuth.js empowers developers to focus on building robust and secure authentication systems with ease.