Drill system design until the answers are reflex.
64 original flashcards on caching, sharding, consistency, estimation and the classic design prompts. Spaced repetition decides what you see next. Progress saves in this browser. No paywall. Sign in with GitHub only if you want a copy that follows you.
Your first card is on screen in one click. Press space to reveal, 1–9 to tick points, enter to rate.
One drill, ninety seconds
The loop is built around how the real interview goes: you talk, the interviewer checks boxes in their head. MetaStack makes those boxes visible.
- 1
Read the prompt and answer out loud
Exactly like the interview. There is a scratchpad if you want to sketch, but speaking is the point.
- 2
Reveal, then tick the points you actually hit
Every card carries a rubric of three to six key points instead of one right answer, because design questions do not have one.
- 3
Your coverage sets the rating; FSRS sets the date
Under 40% is Again, 95% is Easy. The scheduler picks the next review so you see shaky cards soon and solid ones rarely.
Three decks
See due countsFundamentals
Concepts and tradeoffs you will be asked to justify.
Estimation
Napkin math with the numbers interviewers expect you to know.
Classic designs
Complete interview prompts with a rubric for every stage.
Why FSRS and not a fixed schedule
Most flashcard apps still use SM-2 from 1987: fixed multipliers that treat every card the same. FSRS fits a memory model to how you actually rate each card, so a concept you keep fumbling comes back tomorrow while one you nailed waits a month. Fewer reviews, same retention.
The scheduler is a small, pure, fully tested package. Your progress is yours: export it as JSON any time from Settings.
Open source, written by hand
Every card is original Markdown with a rubric and a link to a public engineering blog or docs page. Bad cards fail the build. If you spot a mistake or want to add a card, open a pull request.