This document serves as an index to common HLD interview problems. Each problem includes a comprehensive design walkthrough.
- System Design Problems Collection: https://www.geeksforgeeks.org/most-commonly-asked-system-design-interview-problems-questions/
- System Design Interview Series: https://www.youtube.com/playlist?list=PLMCXHnjXnTnvo6alSjVkgxV-VH6EPyvoX
- System Design Interview Playlist: https://www.youtube.com/playlist?list=PLMCXHnjXnTnvo6alSjVkgxV-VH6EPyvoX
| Problem | Difficulty | Key Concepts |
|---|---|---|
| URL Shortener | Easy | Hashing, Database, Base62 |
| Pastebin | Easy | Similar to URL Shortener |
| Rate Limiter | Easy | Token Bucket, Redis |
| Problem | Difficulty | Key Concepts |
|---|---|---|
| Twitter/X | Medium | Fan-out, Timeline, Caching |
| Medium | CDN, Image Storage, Feed | |
| Notification System | Medium | Pub/Sub, Push, WebSockets |
| Chat Application | Medium | WebSockets, Message Queue |
| Search Autocomplete | Medium | Trie, Caching |
| Problem | Difficulty | Key Concepts |
|---|---|---|
| YouTube/Netflix | Hard | CDN, Video Encoding, HLS |
| Uber/Lyft | Hard | Geospatial, Real-time, Matching |
| WhatsApp/Messenger | Hard | E2E Encryption, Delivery Status |
| Google Docs | Hard | CRDT, Operational Transform |
| Distributed Cache | Hard | Consistent Hashing, Eviction |
- Functional: What should the system do?
- Non-Functional: Scale, latency, availability
- Out of Scope: What we won't cover
- Users: DAU, MAU
- Traffic: QPS, read/write ratio
- Storage: Data size, growth rate
- Bandwidth: Upload/download needs
- Draw major components
- Show data flow
- Identify key decisions
- Database schema
- API design
- Critical algorithms
- Caching strategy
- Identify potential issues
- Scaling strategies
- Single points of failure