Live
About Bottleneckers
A browser load simulator for system architecture. Drag servers, databases, caches and queues onto a canvas, wire them up, push traffic through, and watch which node saturates first — retry storms, latency cascades and all. Free, no signup, and your diagrams never leave the browser.
Build
- Drag-and-drop canvas with six node types: load generator, load balancer, server, database, cache, queue
- Split edge traffic by percentage, absolute QPS or evenly, with live QPS labels on every edge
- Per-node tuning — instances, error rate and latency; read/write split and replicas; cache hit rate; queue consumers
Simulate
- Traffic flows through the graph and re-simulates on every change
- Nodes heat up yellow at 70 %, orange at 90 %, red at saturation
- Models overload, error rates and retry amplification — watch a retry storm happen
- Analysis bar with warnings, the critical request path drawn on the canvas, mean latency and end-to-end success rate
Learn
- Six interactive lessons with live success checks — CPU saturation, database writes, cache-miss storm, load-balancer limits, queue lag, retry storm
- Five starter templates, from a simple web app to an event-driven pipeline
Keep
- Saves in your browser; export JSON, PNG or JPG; share a diagram as a link
- Dark, light and Matrix themes
A closer look
