Breakscale is a system design simulator with 33 components and 23 worked examples, including reconstructions of Netflix, Spotify, Discord, Uber, Twitter/X, Stripe, and WhatsApp architectures.

Users wire components on a canvas, adjust traffic, and observe queueing behavior, latency percentiles, circuit breakers, and retry storms. The engine runs a deterministic discrete-event simulation computing p50, p95, and p99 from actual request objects rather than approximations.