Design a Category-Based Leaderboard

Published 3 October 2026

System Design Round 2 — Category-Based Leaderboard

The second design round asked for a leaderboard organized by category, where rankings needed to be maintained separately for different groups. I discussed how ranking data would be written, stored, and queried across categories.

Real-Time Follow-Up

The interviewer then asked how the architecture should change if rankings needed to update in real time, along with the tradeoffs between the baseline and real-time versions. This round felt particularly positive, and the interviewer appeared engaged with the comparison.