Interview Problems
Real-world system design questions asked at top tech companies.
| # | Problem | Category | Description | Difficulty |
|---|---|---|---|---|
| 1 | URL Shortener | Storage + Hashing | Design a service to shorten long URLs, redirect users, and track analytics. | Easy |
| 2 | Rate Limiter | Throttling | Limit API requests per user or IP within a sliding time window. | Easy |
| 3 | Key-Value Store | Storage | Design a distributed in-memory store like Redis with get/set/delete and TTL. | Easy |
| 4 | Twitter / News Feed | Social / Fan-out | Generate and serve a personalized timeline using fan-out on write or read. | Medium |
| 5 | WhatsApp Messaging | Messaging | Real-time 1-1 and group chat with delivery receipts and offline support. | Medium |
| 6 | Search Autocomplete | Search | Return top-k query suggestions in real time as the user types. | Medium |
| 7 | Notification System | Async / Fan-out | Send email, SMS, and push notifications at scale with reliability. | Medium |
| 8 | YouTube / Video Streaming | Media / CDN | Upload, transcode, and stream video globally with adaptive bitrate delivery. | Hard |
| 9 | Uber / Ride Sharing | Geo / Matching | Match riders to nearby drivers in real time using geospatial indexing. | Hard |
| 10 | Web Crawler | Distributed / Queue | Crawl the entire web at scale with URL deduplication and politeness policies. | Hard |
| 11 | Stock Exchange | Low Latency / Matching | Order matching engine with microsecond latency and strict ordering guarantees. | Hard |