websocket-realtime

---
name: websocket-realtime
description: Real-time communication patterns with WebSocket, Socket.io, Server-Sent Events, and scaling strategies
---

# WebSocket & Real-Time

## WebSocket Server

```typescript
import { WebSocketServer, WebSocket } from "ws";

const wss = new WebSocketServer({ port: 8080 });

const rooms = new Map<string, Set<WebSocket>>();

wss.on("connection", (ws, req) => {
  const userId = authenticateFromUrl(req.url);
  if (!userId) {
    ws.close(4001, "Unauthorized");