Design
Real-Time Gaming Leaderboard
Design a globally consistent real-time leaderboard for a game supporting millions of players with rank queries and score updates.
This is a Low-Level Design (LLD) problem. New to LLD vs HLD? Start here.
01 - Why interviewers ask this
Real-time ranking at scale is a classic sorted-set/skip-list data-structure question — interviewers check that you avoid re-sorting the entire leaderboard on every score update.
02 - Where this system exists in the real world
You interact with this design every day.
Mobile game leaderboards
Esports and competitive gaming rankings
Fitness app activity leaderboards
03 - What you'll master
Solve this once. Know it forever.
Use a sorted-set structure for O(log n) rank updates
Support real-time score update broadcasts
Design for very high-frequency writes
04 - What you'll design
7 functional · 3 non-functional requirements.
Update a player's score in real time
6 more requirements inside
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05 - Companies that ask this
You may face this exact question in your next interview.
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