After a frustrating system design interview, I realized something: I knew the textbook answers, but couldn't explain WHY they worked. So I built **SysBreak** — a free interactive simulator where your system breaks under traffic and you learn by fixing it. DB slows → indexing Server melts → load balancing DB drowns → caching Orders stuck → Kafka Cascade failure → circuit breakers 5 min. Free. No signup. https://zingy-sfogliatella-21d36... It's an early POC. Honest feedback welcome!