Question Bank

Every question, one list

Sandboxed coding rounds that run against a hidden test suite, and written questions graded against a rubric — side by side, because when you are drilling a topic you want both.

10 questions · browse by bank instead

• Design a retry policyRetries are the most common way a small outage becomes a large one.mediumWritten#distributed-systems#lld#reliability25 min
• Design a chat serviceConnection state is the real problem, and ordering is per-conversation, never global.hardWrittenExplain to unlock#consistency#distributed-systems#hld45 min
• Design a collaborative document editorThe hardest consistency question on the list. OT versus CRDT, honestly.hardWrittenExplain to unlock#consistency#distributed-systems#hld45 min
• Design a distributed job schedulerLeader election and at-least-once done properly, with dependencies.hardWrittenExplain to unlock#distributed-systems#hld#reliability45 min
• Design a distributed key-value storeThe question that tests whether you know CAP for real rather than as a slogan.hardWrittenExplain to unlock#consistency#distributed-systems#hld45 min
• Design a distributed rate limiterChoosing the algorithm is half of it. The other half is what happens when the limiter itself fails.hardWritten#distributed-systems#rate-limiting#system-design45 min
• Design a news feedThe fanout question, and the most-asked design round in the industry.hardWrittenExplain to unlock#caching#distributed-systems#hld45 min
• Design a post and follow-graph serviceFeed seen from the write path: id generation, the follow graph, and hot keys.hardWrittenExplain to unlock#consistency#distributed-systems#hld45 min
• Design a ride-matching serviceGeospatial search plus a very high write rate of location updates.hardWrittenExplain to unlock#distributed-systems#hld#storage45 min
• Design a web crawlerThe politeness question. Dedup at billions of URLs is where the naive answer breaks.hardWrittenExplain to unlock#distributed-systems#hld#storage45 min