Free public beta · Modelica Standard Library 4.1 · in your browser

Model and simulate physical systems in your browser.

ModOnda compiles Modelica models to native code and WebAssembly, simulates them with its own solvers, and plots the results beside the diagram. Nothing to install, and the workbench is free to use.

Open the workbench Read the docs

Signing in is optional. The workbench runs without an account.

The ModOnda workbench with a hydraulic aileron actuator model in the diagram view, its package tree on the left and the component panel on the right. — Diagram view of the AileronActuator example from the Modelica Standard Library.

533 of 534: MSL 4.1.0 example models run to the end
517 of 534: match the Modelica reference results
On your device: simulations run in your browser tab by default
Free: public beta, nothing to install

Built for models that are too big to wait on

A Rust core runs the same compiler and solvers on a server and in a browser tab.

Symbolic backend

Alias elimination, Pantelides index reduction with dummy derivatives, BLT sorting and tearing, and exact symbolic Jacobians, evaluated by a compiled register tape.

Solvers you can choose

Variable-order BDF, Radau IIA and ESDIRK with colored Jacobians and dense or sparse LU. Dopri5 switches to BDF when a model turns stiff. RK4 and Euler are there for fixed steps.

Events and discrete logic

Zero-crossing events, when, elsewhen and reinit, and state machines drawn as diagrams.

Workbench in the Dymola style

Package browser, icon, diagram and text views of every class, a variable browser, a plot window with display units, and simulation setup in one place.

Standard Library ready

Modelica Standard Library 4.1.0 loads in the browser, including MultiBody, the QuasiStatic machines, Media (IF97 water, R134a, moist air) and Fluid. 3-D animation replays MultiBody models.

Results and scripting

Results go to Dymola-format .mat files or CSV, readable by Dymola, OMEdit and DyMat.

Inside the workbench

Every view below is a live part of the app, not a mock-up.

A plot window with simulated curves for several variables of a model. — **Plot.** Tick a variable to draw it, with display units and subplots.

The Modelica text view of a class, with syntax colouring. — **Text.** Edit Modelica source with go to definition, rename and completion.

A 3-D animation of an aileron actuator model replayed after a simulation. — **Animation.** Replay a MultiBody model in 3-D after a run.

Validated against the Modelica reference results

Every example of the Modelica Standard Library is run and compared, signal by signal, with the reference results published with the library. 517 of the 534 match, and 533 run to the end.

Pricing

The beta is free, and it takes no payment. Pro is in early access and is not charged yet.

Prices for

Available now

Free

The full workbench and solvers, computed in your browser
Documentation and worked examples
Share a model by link
Your own AI through an OpenRouter key or MCP
Free for personal, educational and commercial work during the beta

Open the workbench

Early access

Pro

$20 a month, or $200 a year, excl. tax

Hosted AI assistant: 300 messages a month, no key of your own needed
30 hours of cloud runs a month for models too big for a browser tab
More assistant messages in packs of 50 for $5, 100 for $10 or 500 for $50
Early subscribers keep this price for 12 months

Waitlist

Team

Later

Shared workspaces for teams
Price to be set with the first teams

Prices are in dollars and exclude VAT and other taxes. The total including any tax that applies to you is shown before you pay. Prices can change before Pro goes live. The paid parts are not live yet, and nothing is charged when you join a list.