Auth.js adoption guide: Overview, examples, and alternatives

Auth.js is a comprehensive JavaScript library designed to simplify and secure user authentication in web applications, offering flexibility in using various authentication strategies, including OAuth and SSO systems. Originating as NextAuth in 2016, the library was rebranded as Auth.js in 2022 to support a broader range of React frameworks beyond Next.js. It boasts built-in support for multiple databases and can function without a database when integrated with OAuth services or JSON Web Tokens. Auth.js is favored for its high performance, lightweight architecture, and ease of integration with Next.js applications, although it faces criticism for limited customization options, migration challenges, and unresolved issues. Despite these challenges, it remains a reliable solution due to its active developer community and extensive resources. When compared to other authentication libraries like Passport.js and Firebase Authentication, Auth.js is noted for its compatibility with Next.js and its extensive provider support, though it may not be ideal for projects requiring deep customizations or those using older technologies.