Design a low-latency online feature store that serves consistent features for real-time ML inference while guaranteeing training/serving parity and point-in-time correctness.
AdvancedMl PlatformFeature StoreStreaming
Real-Time Leaderboard with Anti-Cheat Detection
Design a real-time leaderboard system that serves millions of players with p99 rank reads under 80ms, handles 1.2M score updates/sec, and enforces explainable anti-cheat decisions.
AdvancedLeaderboardReal TimeGaming
Geofencing & Location-Based Alert System
Design a system that triggers real-time alerts when millions of users enter or exit geographic zones, supporting complex polygon boundaries, high-frequency location updates, and sub-second detection latency.
IntermediateGeospatialReal TimeStreaming
Collaborative Document Branching System
Design a branching and merging system for real-time collaborative documents with CRDT sync, conflict resolution, and full audit history.