Socket.io

Summary

A library built on top of WebSockets (with automatic fallbacks) that adds rooms, namespaces, and a simpler event-based API — the most common way to add real-time features to a Node.js app.

• 1Build a basic Socket.io server and client exchanging custom events.
• 2Use Socket.io 'rooms' to broadcast messages to a specific subset of connected clients.
• 3Learn Socket.io's automatic fallback to long polling when WebSockets aren't available.