What is Phoenix Framework?

Phoenix is the web framework for Elixir, analogous to Rails for Ruby or Laravel for PHP. It is known for exceptional performance — handling millions of WebSocket connections on a single server. Key components: Router: maps HTTP requests to controller actions. Controllers: handle requests, call contexts, return responses. Views/Templates: render HTML with HEEx templates. Contexts: bounded domain logic modules (like service layers). Channels: real-time WebSocket communication — each connected user is a lightweight BEAM process. LiveView: server-rendered, real-time interactive UIs — HTML diffs are sent over WebSocket, eliminating most JavaScript. Ecto: database library with changesets for validation. Phoenix leverages BEAM's concurrency — unlike Node.js or Rails, it handles long-lived connections natively without blocking. It is used by Fly.io, Discord (millions of concurrent users), Bleacher Report, and many others.