Multiplayer game state sync
Design the real-time state-synchronization layer for a 60-player battle-royale game. Each match runs ~25 minutes; players send inputs at 60 Hz and need to see other players' positions, projectiles, and hit events with <100 ms perceived lag despite 30–150 ms RTT. The server must be authoritative (anti-cheat), and clients on flaky mobile connections must degrade gracefully. How do you keep all 60 clients consistent at scale across thousands of concurrent matches?
What a strong answer looks like
Clarify scale and constraints first. Propose a clean component breakdown, then go deep on the hard parts (data model, bottlenecks, consistency, failure modes) and name the trade-offs you are making.
Clarify5:30 left
Estimate5:30 planned
Design16:30 planned
Deep dive13:30 planned
Failure9:00 planned
Which questions mattered is sealed until you submit. Telling you now would just be handing over the edge cases.
Run or narrate your approach, then ask the coach.