Start by clarifying requirements and scale, then define core entities and APIs. Focus on real-time move synchronization using WebSockets, game state persistence with a database, and concurrency control. Discuss matchmaking, spectator support, and scaling strategies like sharding and caching.
Pro tip: Emphasize trade-offs: e.g., using WebSockets for real-time but falling back to polling for reliability, and using optimistic locking for concurrency. Show awareness of failure modes and how to handle them.
Ask about expected user base, concurrent games, latency requirements, and features like rating, chat, and tournaments. Define functional and non-functional requirements.
Identify entities: User, Game, Move, Board, Player, Spectator. Design schemas for persistence, considering move history and game state snapshots.
Use WebSockets for bidirectional communication. Server validates moves, updates game state, and broadcasts to players and spectators. Ensure move ordering and idempotency.
Use optimistic locking or versioning to prevent race conditions. Persist moves and game state to a database (e.g., PostgreSQL) with write-ahead logging or event sourcing for durability.
Implement matchmaking via a queue with rating-based pairing. For spectators, use pub/sub to broadcast moves. Scale horizontally with load balancers, sharding by game ID, and caching (Redis) for active games.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.