Real-time game leaderboard
Design a real-time global leaderboard for a competitive game with 80M monthly players: scores update constantly during matches, players want their exact rank and the top-100 to refresh within ~1s, and you also need 'players near my rank' and weekly/seasonal resets. Walk through the data structures and how you keep rank queries fast at this scale.
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.
Clarify4:00 left
Estimate4:00 planned
Design11:30 planned
Deep dive9:30 planned
Failure6:00 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.