30 System Design Case Studies to Learn in 30 Days

By: Neo Kim

If you want to become good at system design (in 30 days), learn these 30 case studies:

1. How Stock Exchange Works
2. How YouTube Works
3. How Google Docs Works
4. How Kafka Works
5. How URL Shorteners Work
6. How WhatsApp Works
7. How Airbnb Works
8. How Spotify Works
9. How Slack Works
10. How Reddit Works
11. How Bluesky Works
12. How Tinder Works
13. How Twitter Timeline Works
14. How Uber Finds Nearby Drivers
15. How Amazon S3 Works
16. How Apple AirTags Work
17. How LLMs Actually Work
18. How ChatGPT Apps Work
19. How Uber Computes ETA
20. How Meta Serverless Works
21. How Live Comments Work
22. How Real-Time Leaderboards Work
23. How Live Presence Works
24. How YouTube Scales MySQL
25. How Vector Databases Work
26. How Pastebin Works
27. How ChatGPT Works
28. How Nginx Works
29. How Lyft Works
30. How Google Search Works

Key Points

• A 30-case-study curriculum for learning system design in 30 days, covering real-world systems
• Ranges across messaging (WhatsApp, Slack, Kafka), social (Reddit, Bluesky, Twitter timeline), infra (S3, Nginx, serverless), and AI (LLMs, ChatGPT, vector databases)
• Commenters note case studies teach the “what”; building a simplified version yourself makes the tradeoffs stick
• Follow Neo Kim’s newsletter for a free System Design Playbook