PrepGrind

Learn system design, DSA & AI by building, not memorizing

Education

Developer Tools

Artificial Intelligence

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Hey Product Hunt 👋 I'm the solo maker behind PrepGrind. I built it out of frustration. When I was prepping for system design interviews, everything was passive - reading articles, staring at static diagrams, memorizing answers I couldn't actually defend. I could say "add a cache to reduce database load," but I had no feel for how much it helped or what would break first under load. You just can't get that from a blog post. So I made PrepGrind - a place where you actually build the system instead of reading about it: 🧩 Drag real components onto a canvas - load balancers, caches, queues, databases, even LLMs and vector DBs ⚙️ Configure each one (cache hit-rate, capacity, rate limits, load-balancer strategy) 📊 Push live traffic through it and watch real-time throughput, latency and error rates on every node 🔴 Crank the load until something turns red - it flags exactly what fails under pressure (bottlenecks, single points of failure) 🟢 Add capacity and watch it recover in real time You learn the trade-off by seeing it, not memorizing it. It's more than system design too - there are 35+ real case studies (URL shortener, chat, video streaming, RAG, recommendation engines…), a DSA pattern tracker with a personalized prep plan, and an interactive AI module that visually unpacks how things like attention, embeddings and RAG actually work. It runs right in your browser - free to start, no signup needed. I'm building this solo and would genuinely love your feedback: 👉 Does the simulation help your intuition, or does the approximation bug you? 👉 What case study or feature should I add next? Thanks so much for checking it out 🙏