System designHardsd-g705

Subject Matchmaking realtime networkingLevel Senior–Staff~45 minCommon in Networking & APIs · Distributed systems · Algorithms & data structures interviewsIndustries Computer games, Technology

Question

Design a real-time matchmaking service for an online multiplayer game with 5M daily players that pairs players into balanced matches in under 30 s while keeping per-player network latency to the chosen game server low. It must balance skill (fair matches), latency (low ping), and queue time (don't make people wait). How do you run the queue, pick servers near players, and resolve the inherent tension between these goals?

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.

Learn the concepts

Narrate your design

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Run or narrate your approach, then ask the coach.