YourSimulation Engine

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YourSimulation EngineOpen-source discrete-event simulation

A zero-dependency TypeScript engine for service, queue, and network systems — estimate waits, utilization, and throughput, and find the cheapest design that meets a service target. MIT licensed.

API & CLI
Blocks
Examples
Try the app

12 building blocks

source, queue, resource, delay, seize/release (+ resource pools), assign, batch, separate, match, branch, sink — compose any service or network system.

Models the real world

Reneging and balking, join-shortest-queue and class-based routing, shared resources held across steps, preemptive priority, machine breakdowns, and assembly.

Rigorous & reproducible

Seeded replications with 95% confidence intervals, validated against closed-form queueing theory — M/M/1, M/M/c, Erlang-A, M/M/1 preemptive priority, and breakdown availability.

Run & optimize headless

A CLI and a clean library API — run experiments and a Cross-Entropy optimizer from the command line or your own code, with zero runtime dependencies.

YourSimulation Studio ​

▶ Launch the Studio — free, in your browser →

The open-source engine documented here also powers YourSimulation Studio — a free, browser-based visual model editor, experiment runner, and optimizer. No install, no account: open the page and start modeling.

  • Drag-and-drop editor — build any service / queue / network system from 12 blocks on a themed canvas.
  • Answers with error bars — seeded replications report waits, utilization, and throughput with 95% confidence intervals.
  • Watch mode — deterministic animated playback skinned for airports, hospitals, logistics, and networks.
  • Optimize, don't guess — a Cross-Entropy search finds the cheapest design that still meets your service target.
  • AI companion — a bring-your-own-key agent that proposes model edits from plain language.

Free to use — the Studio is free, and this engine underneath is open-source (MIT). Try it on a worked example: airport security, hospital triage, a bank branch, a factory line with breakdowns, a saturated restaurant, or a 100k-client CDN network — all ready to run.

Keep exploring ​

  • 📘 Documentation — the Studio app guide & reference
  • 🎓 Tutorial — model an airport step by step
  • 🗂️ Examples — domain models with KPIs and 95% CIs
  • 🧩 Blocks reference — every building block, explained
  • 🧰 Intro Kit — the fastest path from zero to a running model