websocket-protocol-designer

Purpose

Architect reliable, low-overhead real-time messaging protocols over WebSockets or Server-Sent Events (SSE), incorporating connection lifecycle handshakes, heartbeat ping/pong keep-alives, exponential reconnect backoff, channel multiplexing, and reconnection state recovery.

When to Use

• Building real-time collaborative editors, live chat, trading dashboards, or notification feeds.
• Fixing zombie WebSocket connections that silently drop behind NAT firewalls.
• Implementing message ordering and missed message replay after temporary disconnection.

What to Analyze

1. Protocol Selection: WebSocket (bidirectional) vs SSE (unidirectional server-to-client with native HTTP/2 multiplexing).
2. Frame Format: Lightweight JSON envelopes vs Binary MessagePack/Protobuf for high-frequency data.
3. Heartbeat & Liveness: 30-second ping/pong frames to detect dead sockets through intermediate proxies.
4. Reconnection & Catch-Up: Client reconnects with last_event_id; server streams missed events from Redis buffer.
5. Authentication & Authorization: Ticket-based token exchange during connection handshake vs query param auth.

Output Format

• Message Envelope JSON Schema: Standard frame format (type, channel, id, payload, ack).
• Connection State Machine: Client connection lifecycles (CONNECTING, CONNECTED, RECONNECTING, CLOSED).
• Server/Client Implementation Snippets: TypeScript / Node / Go socket handler with ping/pong management.

Avoid

• Authenticating sockets by passing static JWT tokens in URL query strings (leaks into proxy access logs).
• Missing backpressure controls when broadcasting to slow mobile clients.