System Design Arcade vs System Design Refresher

Most system design prep is paid and online. System Design Arcade is free, works offline, and keeps your progress on your device. The system design interview is the one where the whiteboard goes blank. You've read the books. You've watched the videos. But when the interviewer says "design Instagram," you freeze — because reading about consistent hashing at 2am is not the same as knowing it cold. System Design Arcade is the fix. It turns every building block — caching, sharding, load balancing, rate limiting, CAP theorem, consistent hashing — into 60-second arcade levels you can actually finish. On the subway. In line for coffee. While waiting for CI. On a plane with no Wi-Fi. WHY ARCADE BEATS EXPENSIVE COURSES 5-minute mini-games beat 5-hour video courses you never finish. Active recall beats highlighting. And nothing beats free. THREE TRACKS, ONE CURRICULUM Concepts — master one building block at a time. Caches, databases, queues, replication, sharding, load balancing. Everything that shows up in the first thirty minutes of the interview. Problems — design complete systems end-to-end. URL Shortener, Rate Limiter, News Feed, Chat, Ride Sharing. The classics, played out like boss fights. Tools — hands-on drills with the infrastructure you'll actually use on the job. Redis. Kafka. Docker. Kubernetes. Story Mode — narrative capstones that show WHY Netflix shards by user_id, WHY Twitter chose Redis for the timeline, WHY Discord built their own pub/sub. CHALLENGE TYPES THAT DON'T FEEL LIKE FLASHCARDS Multiple choice, ordering puzzles, fill-in-the-blank, API Builder, Architecture Builder, and Scenario-Why drills — each level mixes formats so your brain has to actually engage. The Scenario-Why drills are the secret weapon: they train the reasoning behind the answer, not just the answer. DAILY CHALLENGE A fresh challenge every day, picked deterministically so you and your study buddy see the same one. Streak counter. Optional reminder notifications (opt in from Settings) so you don't break the streak. BUILT FOR YOUR EYES Retro arcade aesthetic by default. Pixel fonts. Neon glow. If that's not your thing, switch to the playful sticker-card vibe or open the Theme Lab and tune background, glow, gradient, and font until it feels right. Read Aloud narrates every explanation — learn while you walk. YOUR PROGRESS STAYS YOURS By default, everything saves on-device with no account required. No tracking pixels in your answers. Sign in with Apple anytime from Settings to back up your progress and sync it across your iPhone and iPad. We use privacy-friendly product analytics to see which levels need work — never the content of your answers. FREE TO PLAY, FULL CONTENT INCLUDED No ads. No paywalls. No gated levels. No subscription. New games ship every sprint. Start with Level 1.

System Design Refresher is a free study companion for software engineers preparing for system design interviews. WHAT'S INSIDE • 30+ system design articles covering distributed systems, databases, caching, and more • Engineering blogs from top tech companies (Google, Meta, Stripe, Airbnb, and more) aggregated in one place • AI-powered flashcards with spaced repetition • Ask AI to summarize or explain any article in plain language • Favorites, reading progress tracking, and custom RSS feeds FEATURES • Works offline — articles download for reading without internet • Dark mode, font customization, and text size controls • Face ID / Touch ID lock for privacy • Sign in with Google or Apple, or use as a guest with no account required