About SysGeeks

13 systems to design, split into 132 stages; 35 concepts explained from the problem they solve to the way they fail; and 13 companies whose engineers published how they solved the same problems. There is also a guide to the interview itself and a timed mock interview.

Every system starts from a scenario with explicit requirements, constraints and assumptions, the way a real design review does. The stages then follow the same loop: model the problem, decide between designs that all sound plausible, break the design with a concrete failure, change a constraint, and defend what is left.

Each stage asks you to commit to an answer before it shows the reasoning, including where another engineer could reasonably land differently. Every system also has a full written walkthrough with the finished architecture, its invariants, its tradeoffs and the point where it stops working.

The systems are built from how real companies describe their own designs: 22 engineering posts, papers and talks from 13 companies, each linked from the pages that draw on it. Where a design follows a published account, the page says so and links to the original, so you can check the reasoning against the engineers who built it.

The concepts avoid product names wherever a mechanism will do: a page about queues explains acknowledgements and redelivery, not a particular broker.

Nothing is graded by AI. Choices, verdicts and orderings are checked against an authored answer key. Written explanations are compared by you against specific points in a reference answer, so your progress is only as honest as your own marks, and it says so.

There are no accounts. Your answers and projects are stored in your browser, and you can export or delete them from your progress.