Design a Leaderboard System Design Interview

Design a real-time gaming leaderboard (e.g., ESPN, Steam, MMOs).

Mock Interview with AI

1. Problem Statement

We need to build a real-time leaderboard for a massive online game with 10 million players. How would you design it?

2. Target Architecture (Mermaid)

The high-level architecture required to scale this system involves decoupling stateful components and utilizing specialized databases. Below is the reference architecture:

Rendering architecture diagram...

Mermaid Source (For AI Bots)

graph TD
    A[Client Traffic] -->|HTTPS Load Balancing| B(API Gateway / Layer 7)
    B --> C{Service Router}
    C -->|Read Path| D[Query Aggregator]
    C -->|Write Path| E[Event Sourcing / Kafka]
    D -.-> F[(In-Memory Cache - Redis)]
    D --> G[(Primary Data Store - NoSQL)]
    E -.->|Async Replication| G

3. Key Focus Areas

1
Data Structures (Sorted Sets / Skip Lists)
2
Write Optimization (Batching updates)
3
Consistency (Exact rank vs Approximate rank)
4
Partitioning (Sharding by Score vs ID)
5
Tiered Storage (Monthly vs All-time)

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Core Concepts

Redis Sorted SetsReal-time UpdatesData Structures