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Design an Online Game Leaderboard

MetaSoftware Engineer · Technical Screen
HardSoftware EngineerTechnical ScreenSystem Design

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A Meta software-engineer system-design screen: design the backend for an online game leaderboard supporting score recording, a global top-N board, a friends board, a player's rank and nearby players, and daily/weekly/seasonal/all-time windows at high write volume and low read latency. The model answer separates a durable score event log from an in-memory sorted ranking store, computes the friends board on read, and covers tie-breaking, caching, sharding, consistency trade-offs, anti-cheat, and rebuilds.

Question

Design the backend system for an online game's leaderboard.

The system should support:

  1. Recording and updating player scores from game sessions, with high write volume from many concurrent players.
  2. A global leaderboard showing the top N players by score (for example, the top 10 or top 100).
  3. A friends leaderboard showing the top players among a given user's friends.
  4. A player's own rank plus the nearby players around that rank (an "around me" view).
  5. Multiple leaderboard windows such as daily, weekly, seasonal, and all-time rankings.
  6. Low-latency reads for leaderboard pages even at very large scale.

Walk through the functional and non-functional requirements, the API design, the data model, storage choices, the ranking strategy (including tie-breaking), caching, the scaling approach, consistency trade-offs, anti-cheat/validation, and operational concerns. Explain how you keep the global, friends, windowed, and rank/nearby queries efficient when the player base and write volume are large.