Passport.js

Passport.js is a popular authentication middleware designed specifically for Node.js. Its primary strength lies in its flexibility and modular design, allowing it to be integrated into any Express-based web application without significant code changes. The core idea is to delegate all authentication-related tasks to specialized modules known as 'strategies'.

This approach makes the system highly extensible. You can choose from a vast library of over 500 strategies to handle various authentication mechanisms. This includes:

• Traditional username and password logins.
• Single sign-on (SSO) with social providers like Facebook, Google, Twitter, and GitHub.
• Enterprise solutions using protocols like SAML or OpenID.

By keeping the core minimal and relying on individual strategies, you can easily add or switch authentication methods as your application's needs evolve. This makes it a go-to solution for developers looking for a simple yet powerful way to secure their Node.js applications.