A gamified, Anki-style web app for practicing back-of-napkin math for system design interviews. 10 random questions per round from a bank of 30+, covering multiple system design topics.
- 30+ questions across multiple topics: APIs, Databases, Scaling, CAP Theorem, Auth & Security, Load Balancers, Caching, Message Queues, Indexing, Failovers, Replication, Consistent Hashing, Networking, etc.
- Expression input: Type calculations like
1000 * 10 / 4directly in the answer box - Instant feedback: Correct/incorrect with directional hints (too high/too low), reference answers, explanations, and tips
- Score tracking: Per-topic breakdown after each game, historical scores persisted in localStorage
- 10 random questions per game: Different mix each time from the full question bank
Open index.html in a browser, or visit system-design-math-practice.tzvi.dev.
Two Agent skills are included for managing the question bank:
/audit-questions # Read-only audit of all questions (math, ranges, clarity)
/audit-questions --fix # Audit and auto-apply corrections
/add-questions # Research and add new questions (picks gaps automatically)
/add-questions DNS # Add questions for a specific topic
Vanilla HTML/CSS/JS — no framework, no build step. Deployed to GitHub Pages.
This project is licensed under the MIT License.
Refined by the Impeccable Skills