System Design

How do products like ride-hailing, streaming and messaging platforms actually work end to end? This section takes real systems apart: what they had to build, where it broke as they grew, and the engineering decisions that fixed it.

Case studies

The first case studies are being written. Check back soon.

How each case study is structured

Every case study follows the same arc, so you can compare systems side by side:

1. Requirements: what the product must do, functionally and non-functionally.
2. Scale and constraints: traffic, data volume, latency and availability targets.
3. High-level architecture: the main services and how requests flow between them.
4. Deep dives: the interesting components, such as matching, storage and real-time delivery.
5. What broke at scale: the real problems the team ran into as usage grew.
6. How it was solved: the redesigns, trade-offs and technologies chosen.
7. Takeaways: patterns you can reuse in your own designs and interviews.