I Built an Interactive System Design Simulator — Learn by Breaking Things
The Problem Every system design resource teaches the same way: here's a concept, here's a diagram, memorize it. But in real interviews, you need to APPLY these concepts under pressure. What I Built A free interactive simulator where your architecture breaks under increasing traffic, and you learn system design concepts by fixing it. How It Works You start with 1 server + 1 database (100 users —…
Every system design resource instructs learners the same way: introduce a concept, present a diagram, and require memorization. However, real interviews demand application of those concepts under pressure. To address this gap, I created a free interactive simulator that simulates architecture breakdowns as traffic grows, teaching system design principles by fixing the issues that arise.
The simulator begins with a single server and database supporting 100 users, depicted in green. As demand escalates to 1,000 users, the database slows down, prompting the learner to discover the value of indexing. At 10,000 users, the server's CPU usage reaches 96%, leading to the lesson on load balancing. When traffic hits 100,000 users, the database becomes overwhelmed, highlighting the need for caching (Redis).
With 1,000,000 users, individual orders take 8 seconds to process, teaching the importance of Kafka for asynchronous processing. Finally, at 10,000,000 users, the system experiences a cascade failure, leading to the understanding of circuit breakers.
The simulator offers a comprehensive learning experience by the end, as learners have constructed a production-grade distributed system and grasped the purpose behind each component. The platform is currently free and does not require registration, accessible at https://clinquant-figolla-de3a06.netlify.app/.
Future developments include introducing ten distinct crisis scenarios, such as Black Friday surges, DDoS attacks, cache stampedes, and more. An "Interview Lab" feature will enable learners to diagnose and fix their system when it breaks, thereby answering real interview questions. The simulator currently employs vanilla HTML/JS for a proof-of-concept, with plans to expand the full product to include React, TypeScript, Vite, and Supabase.
The creator welcomes feedback on additional concepts that learners would benefit from mastering through this interactive approach.
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