Passport.js

Passport.js is a popular authentication middleware for Node.js, providing a comprehensive set of strategies for authentication using various methods, including username and password, Facebook, Twitter, and more. It is extremely flexible and modular, making it easy to integrate into any Express-based web application. With over 500 strategies available, Passport.js is a widely-used solution for authentication needs. It is also open-source, allowing for community contributions and customization. Passport.js is designed to be unobtrusive, making it easy to drop into any existing application. The library is well-maintained, with a strong community of developers contributing to its development and support.