System design is hard to learn from a diagram.

Most system design material is static: a whiteboard photo, a slide deck, a wall of text explaining why load balancers matter. You read it, nod along, and then freeze the first time an interviewer asks you to actually draw one.

System Design Simulator is a canvas instead of a slide. You drag real components — clients, load balancers, caches, databases, queues — onto a board and wire them together. Every connection carries real throughput, latency, and cost. Nothing is hypothetical: if you forget a load balancer, your single API server becomes a single point of failure, and Chaos Monkey will find it.

The goal isn't to memorize a checklist of components. It's to build the instinct for how a system behaves under load, what breaks first, and why the trade-offs (SQL vs. NoSQL, strong vs. eventual consistency, monolith vs. microservices) actually matter in a specific design — not in the abstract.

Guided levels walk through a progression, from a plain URL shortener to a distributed, highly-available system that has to survive any single component failing. Sandbox mode drops the guardrails so you can design freely, simulate traffic, and stress-test whatever you build.

It's built for the same audience it was built by: people preparing for system design interviews, students who want to see the theory move, and engineers who learn better by breaking things on purpose than by reading about them.