Design a Fault-Tolerant Online Chess Service
Company: OpenAI
Role: Software Engineer
Category: System Design
Difficulty: medium
Interview Round: Technical Screen
Overview: Design a fault-tolerant online chess service with authoritative move ordering, server-managed clocks, reconnects, spectators, and recovery from application failure. Validate moves against game versions, make retries idempotent, persist an append-only game history, and handle failover without duplicating moves.