WebSocket Chat (FastAPI)

Context

Real-time chat application demonstrating WebSocket implementation with FastAPI.

Problem & Goals

  • Build low-latency chat system
  • Demonstrate WebSocket handling
  • Show auto-reconnection patterns
  • Include basic metrics

Constraints & Risks

  • Single server deployment
  • In-memory state (Redis for scaling)
  • Basic authentication

Architecture & Alternatives

  • FastAPI WebSocket endpoints
  • Redis for message persistence
  • Simple HTML/JS frontend

Trade-offs

  • Simplicity over scalability
  • Development speed over production features

Results & Metrics

  • Sub-100ms message latency
  • Auto-reconnection on disconnect
  • Basic connection metrics

What I'd change next time

  • Add proper authentication
  • Implement message persistence
  • Add horizontal scaling