systemInPain - Learn system design by watching it break in real time

Hey Product Hunt 👋 Most "system design practice" is either a whiteboard with no feedback, or a quiz that scores you for having the right buzzwords in the right boxes. I wanted something that actually tells you when you're wrong — the way a real system does, under real load. systemInPain is a system design game where you drag components (load balancers, caches, queues, replicas...) onto a canvas, wire them into an architecture, and hit simulate. A deterministic engine runs seeded traffic through your graph and measures what actually happens: p99 latency, availability, cost per hour, throughput. Get the fan-out wrong and load doubles instead of halves. Skip the cache and watch your DB melt. Forget a queue and bursts drop requests. It's graded, not guessed. 15 levels take you from a basic TinyURL clone through flash-sale traffic spikes, read replicas, CDNs, async write queues, failover, and bot/DDoS traffic — each one teaching a single, specific lesson you can see land or fail. Level 1 is free, no signup. It's still early — would love your feedback (there's a link right in the footer, it comes straight to me). Try it: systeminpain.com