High-Level Design

How to use this track

These guides walk through classic high-level design interviews such as a URL shortener, rate limiter, chat system, news feed and payment system. Each follows the same interview-ready structure: requirements, capacity estimates, API, data model, high-level architecture, deep dives and trade-offs.

Start with the building-block topics like consistent hashing, unique ID generation and key-value stores, because the larger designs reuse them. Then practise the bigger systems by talking through them out loud in 35 to 45 minutes, the length of a real round.

After reading a design, close the page and redraw the architecture on paper. Explain one trade-off you would change at ten times the scale. The System Design cheat sheet is a good companion for revising the core concepts.

Interviewers care less about a perfect diagram and more about how you clarify requirements, estimate load and justify each choice, so practise saying your reasoning, not just drawing boxes.