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Design a game leaderboard service
Design a Game Leaderboard Service
Design a backend service that powers leaderboards for an online game.
Core Functionality
- Players submit score updates (or score deltas) for a given game mode and season.
- Clients can query:
- Top K players for a leaderboard (e.g., top 100).
- A given player's current rank and score.
- A range around a player (e.g., ranks 9,950–10,050).
- Support ties deterministically (e.g., same score → break ties by earliest timestamp or player_id).
Non-Functional Requirements
- Large scale (e.g., tens of millions of players; up to hundreds of thousands of score updates/sec at peak).
- Low read latency (e.g., p95 < 100 ms for top-K queries).
- "Near real-time" freshness (e.g., leaderboard reflects updates within a few seconds).
- High availability across regions.
Constraints / Discussion Points
- Score update semantics: only allow monotonic increase (best score) vs allow arbitrary overwrites.
- How to handle seasons/resets, multiple regions, and multiple game modes.
- How to prevent/mitigate cheating and abusive update patterns.
Provide APIs, data/storage design, scaling strategy, and consistency tradeoffs.
AI interview prep
Core dilemma
Balancing the high throughput of score updates against the need for low-latency, accurate retrieval of ranked player data, especially with ties and dynamic leaderboards.
Mid-level signals3
Senior signals4
Red flags4
3 tradeoffs and 3 stress tests locked
Interview prep
Unlock the interviewer X-Ray rubric, tradeoff matrix, stress tests, clarifying questions, and key concepts.
Design a game leaderboard service
Design a Game Leaderboard Service
Design a backend service that powers leaderboards for an online game.
Core Functionality
- Players submit score updates (or score deltas) for a given game mode and season.
- Clients can query:
- Top K players for a leaderboard (e.g., top 100).
- A given player's current rank and score.
- A range around a player (e.g., ranks 9,950–10,050).
- Support ties deterministically (e.g., same score → break ties by earliest timestamp or player_id).
Non-Functional Requirements
- Large scale (e.g., tens of millions of players; up to hundreds of thousands of score updates/sec at peak).
- Low read latency (e.g., p95 < 100 ms for top-K queries).
- "Near real-time" freshness (e.g., leaderboard reflects updates within a few seconds).
- High availability across regions.
Constraints / Discussion Points
- Score update semantics: only allow monotonic increase (best score) vs allow arbitrary overwrites.
- How to handle seasons/resets, multiple regions, and multiple game modes.
- How to prevent/mitigate cheating and abusive update patterns.
Provide APIs, data/storage design, scaling strategy, and consistency tradeoffs.