Passport.js
Passport.js is a popular authentication middleware for Node.js applications that provides a simple, modular way to handle user authentication. It supports over 500 authentication strategies, including OAuth, OpenID, and local username/password, allowing developers to integrate various login methods seamlessly. It is designed to be unobtrusive and works with any Express-based web application.
Developers should use Passport.js when building Node.js applications that require user authentication, such as web apps, APIs, or services needing secure login mechanisms. It is particularly useful for implementing social login (e.g., via Google or Facebook), single sign-on (SSO), or custom authentication flows, as it abstracts complexity and reduces boilerplate code. Learning Passport.js is essential for creating secure, scalable authentication systems in the Node.js ecosystem.