Oauth2 Authentication

This is the comprehensive OAuth2 reference you'll want when implementing anything from social login to M2M authentication. It walks through all the grant types with actual flow diagrams and when to use each one, covers PKCE for SPAs and mobile apps, and explains token management strategies without assuming you already know the difference between authorization and resource servers. The best part is the practical guidance: it tells you straight up that implicit flow is deprecated and why, explains device flow for smart TVs and CLI tools, and covers the security considerations that matter in production. If you're migrating from sessions to tokens or building an authorization server from scratch, this gives you the full picture in one place.