Mobile game leaderboard
Design a small leaderboard for a mobile game with about 100,000 players. When a player finishes a game their score updates, and the app shows the global top 100 plus the player's own rank and a few players around them. Scores change frequently and the leaderboard is read often. Cover how you store scores, how you compute a player's rank, and the main performance trade-off.
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.
Clarify3:30 left
Estimate3:30 planned
Design10:00 planned
Deep dive8:00 planned
Failure5:00 planned
Which questions mattered is sealed until you submit. Telling you now would just be handing over the edge cases.
Run or narrate your approach, then ask the coach.