LeetCode Prep

System Design Sandbox

Drag components, wire an architecture, and load-test it against real scenarios.

System design sandbox

Build an architecture for each scenario, then run a load test. The model is simple on purpose — capacity per component, cache hit rates, and failure events — so you can see why each building block exists.

Serve 10× reads

Your recipe app hit the front page. Traffic jumped 10× to 3,600 requests per second, and 95% of them are reads of the same popular recipes. The single database is at 120% CPU. Keep p95 latency under 200 ms with less than 1% errors.

Palette — drag onto the canvas or click to add

Drag components from the palette, then use each component's → handle to connect it.

Designs save automatically in this browser. Del removes · Esc cancels.

Keyboard-friendly editor

Add a component

Components

Client

Connect two components

Connections

None yet.