I went straight to the backend and started drawing out matchmaking queues before the interviewer even finished nodding.
Start by clarifying requirements and constraints, then propose a high-level architecture that balances peer-to-peer communication with server-assisted coordination. Focus on the core challenges of real-time gameplay, state synchronization, and reliability, and discuss trade-offs between pure P2P and hybrid approaches.
Pro tip: Emphasize that a pure P2P architecture is impractical for mobile chess due to NAT traversal, offline players, and cheating concerns; instead, advocate for a hybrid model where a lightweight server handles matchmaking and move validation while gameplay uses direct P2P connections when possible.
Ask questions to understand scale, latency needs, offline support, and security requirements. Define functional and non-functional requirements such as real-time moves, matchmaking, and anti-cheat.
Propose a hybrid architecture with a central server for matchmaking, authentication, and move validation, and a P2P layer for direct game communication. Explain how components interact.
Detail the matchmaking service, P2P connection establishment (using WebRTC or similar), move synchronization protocol, and state reconciliation. Discuss data models for games and moves.
Discuss trade-offs between latency, reliability, and complexity. Cover NAT traversal, offline handling, cheating prevention, and scalability. Explain why certain choices were made.
Recap the design, highlight how it meets requirements, and suggest potential enhancements like spectator mode or AI integration. Be open to feedback and alternative approaches.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.