Design an Online Chess Platform: Elo Matchmaking, WebSocket Moves, Game Clocks
Company: OpenAI
Role: Software Engineer
Category: System Design
Difficulty: hard
Interview Round: Onsite
Overview: Design an online chess platform: match players of similar Elo rating quickly, deliver moves in real time over WebSocket connections, and enforce fair game clocks despite network latency and disconnections. It tests matchmaking, stateful real-time architecture, server-authoritative timing and failover.