system-design-simulator

Interactive system design practice: build a design, add users, see what breaks.

Sr. Architect: where you can learn, evaluate and plan your next system design

Free, no-signup system design interview practice. Make design decisions, diagnose failures, and adapt to changing constraints across interactive questions and full walkthroughs: URL shortener, ride-sharing dispatch, payments, news feed, and more.

Interactive system design simulator in the browser. Drag load balancers, caches, databases, queues and VPCs onto a canvas and run a real queueing-theory simulation (M/M/c, Erlang-C) to find bottlenecks and single points of failure. Zero backend — great for system design interview prep.

Gamified System Design Learning Platform, guidance faded teaching

Most Realistic System Design Simulator