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Frontend Academy · Lesson

WebSocket API: open message close error

Create a WebSocket connection, send and receive messages in the message event handler, and handle connection errors and clean closure.

Why WebSockets?

HTTP is request/response. For real-time apps (chat, multiplayer games, live updates), you need persistent two-way communication. WebSockets give you a single TCP connection that stays open and lets both sides send messages at any time.

Creating a WebSocket

Construct a WebSocket with a ws:// or wss:// URL. The browser handles the upgrade handshake.

const ws = new WebSocket('wss://api.example.com/realtime');

// Always use wss:// (secure) in production

All lessons in this course

  1. WebSocket API: open message close error
  2. Socket.io Client Integration
  3. Server-Sent Events for One-Way Streaming
  4. Real-time UI Patterns
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