jaredhanson/passport

Passport is an authentication library for Node.js, that is, a set of tools that handles the "who are you?" part of a web application. Authentication is the process of verifying a user's identity before allowing them into a protected area of your app, and building it from scratch every time is tedious and error-prone. Passport solves this by providing a consistent interface that works with Express, one of the most popular Node.js web frameworks. The key concept is a "strategy", a pluggable module that implements a specific way of authenticating users. Passport ships with support for the classic username-and-password approach, but there are over 480 community strategies covering login via Google, Facebook, GitHub, and other social platforms (using the OAuth standard), enterprise single sign-on systems (using protocols like SAML and OpenID Connect), and API token-based approaches. You pick the strategies your app needs, configure them, and Passport handles the rest, including maintaining login sessions across multiple requests. You would use Passport when building a Node.js web application that needs user accounts. It is especially useful when you want to support multiple ways to log in, for example, both a traditional email/password form and "Sign in with Google", without writing separate authentication logic for each one. Passport deliberately stays out of your way: it does not dictate how you store users in a database or how you structure your routes, so it fits into existing projects without requiring a major redesign. It is written in JavaScript and requires Node.js.