Cheat sheet for system design interviews: A repeatable framework for system design interviews

A 16-page cheat sheet built for senior/staff software engineers: a 5-step answer framework, capacity estimation numbers, and 10 fill-in-the-blank playbooks for the questions that come up again and again — URL shorteners, rate limiters, chat systems, and more.

Hey Product Hunt 👋 I'm a software architect, and I built this because I kept seeing the same problem in system design interviews (both prepping for them and later reviewing them as an interviewer): candidates who knew the material but never imposed structure on their answer, and lost points for it anyway. So I wrote down the actual framework — 5 steps, in the order interviewers grade for — plus playbooks for the 10 patterns that show up over and over (URL shortener, rate limiter, chat systems, news feed, notification systems, and more). Each playbook includes the likely deep-dive questions and the trade-offs worth saying out loud. It's built to be used, not read once and forgotten — rehearse 3-4 playbooks closest to your target company's domain, keep the framework in your head, adapt on the fly. Would love feedback from anyone who's been through this loop recently — what am I missing, what would you add for the next version?

16 pages is the right amount, not a 200 page monster I will never read. The fill in the blank playbooks are the real win, I actually finished a couple on a slow Friday and felt way sharper walking into my next loop.

@metin864630 This is exactly the reaction I was going for — I've read too many "complete guides" that are 200 pages of padding nobody finishes. Glad the playbooks actually got used instead of just being bookmarked. How'd the loop go? Curious which pattern ended up mattering most.