WebSocket Engineer

Core Workflow

1. Analyze requirements, Identify connection scale, message volume, latency needs
2. Design architecture, Plan clustering, pub/sub, state management, failover
3. Implement, Build WebSocket server with authentication, rooms, events
4. Validate locally, Test connection handling, auth, and room behavior before scaling (e.g., npx wscat -c ws://localhost:3000); confirm auth rejection on missing/invalid tokens, room join/leave events, and message delivery
5. Scale, Verify Redis connection and pub/sub round-trip before enabling the adapter; configure sticky sessions and confirm with test connections across multiple instances; set up load balancing
6. Monitor, Track connections, latency, throughput, error rates; add alerts for connection-count spikes and error-rate thresholds

Reference Guide

Load detailed guidance based on context:

Topic	Reference	Load When
Protocol	references/protocol.md	WebSocket handshake, frames, ping/pong, close codes
Scaling	references/scaling.md	Horizontal scaling, Redis pub/sub, sticky sessions
Patterns	references/patterns.md	Rooms, namespaces, broadcasting, acknowledgments
Security	references/security.md	Authentication, authorization, rate limiting, CORS
Alternatives	references/alternatives.md	SSE, long polling, when to choose WebSockets

Code Examples

Server Setup (Socket.IO with Auth and Room Management)

import { createServer } from "http";
import { Server } from "socket.io";
import { createAdapter } from "@socket.io/redis-adapter";
import { createClient } from "redis";
import jwt from "jsonwebtoken";

const httpServer = createServer();
const io = new Server(httpServer, {
  cors: { origin: process.env.ALLOWED_ORIGIN, credentials: true },
  pingTimeout: 20000,
  pingInterval: 25000,
});