Free System Design: Learn System Design by Building It
Free System Design is a hands-on course that teaches the principles behind every modern
web system. Instead of memorizing diagrams, you drag real components like load balancers,
servers, caches, databases, and queues onto a canvas, connect them, and run a live traffic
simulation to see exactly where your design breaks and how to fix it.
It takes a complete beginner from their first web request all the way to confidently
answering a real system design interview question. The first lessons are
free to use with no account needed.
What you will learn
- Foundations:web requests, HTTP, APIs, latency vs throughput, stateless servers, sync vs async
- Scaling the web tier:load balancers, horizontal vs vertical scaling, health checks, auto-scaling, sessions, CDNs
- Caching:why caches exist, cache-aside, write-through vs write-back, invalidation, multi-tier caching
- Data layer:SQL vs NoSQL, indexes, replication, sharding, consistent hashing, ACID, eventual consistency
- Async & real-time:message queues, pub/sub, event-driven architecture, WebSockets, webhooks, rate limiting
- Reliability:single points of failure, failover, circuit breakers, retries, idempotency, disaster recovery
- Operating systems in production:logging, metrics & alerting, containers, CI/CD
- The interview:a repeatable 6-step method, plus full design problems like building a URL shortener
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