websocket-realtime-expert

What problem does it solve?

Real-time communication systems often suffer from dropped messages, inconsistent presence, poor reconnection behavior, and difficulty scaling across multiple servers; this Skill provides patterns and operational checks to build robust, resumable, and scalable WebSocket, SSE, and Socket.io services so clients experience reliable live updates and bidirectional messaging.

Core Features & Use Cases

• Protocol guidance for choosing between WebSocket, SSE, WebTransport, and Socket.io depending on bidirectionality, latency, and browser compatibility.
• Resilience patterns including exponential backoff with jitter for reconnects, Last-Event-ID or sequence-based resume, heartbeat/ping-pong presence, and backpressure strategies.
• Scaling & backplane advice for Redis Pub/Sub, NATS, or @socket.io/redis-adapter to broadcast messages across servers and avoid single-server state assumptions.
• Presence & session management with heartbeat-based timeouts, sweep strategies for stale sessions, and event-based notifications for joins/leaves.
• Fallbacks & managed options such as SSE fallbacks for degraded environments and integration options with Ably, Pusher, Supabase Realtime, or PartyKit.
• Operational checklist covering authentication on upgrade, monitoring connection counts, load testing connection targets, and graceful degradation strategies.

Quick Start

Design a scalable WebSocket system that uses Socket.io or ws, implements heartbeat-based presence and Last-Event-ID resume, has reconnection with exponential backoff and jitter, and uses Redis or NATS as a backplane for horizontal scaling.