Alpha · not yet generally available

SysML v2 authoring in your browser

Write SysML v2 as text or draw it as a diagram — both stay in sync. The OMG standard library is built in, with autocomplete and hover documentation. Nothing to install.

Open the editor Join the alpha programme

What it is

A focused environment for SysML v2. If you need other notations alongside it, that is UMStudio.io — see below.

Text and diagram, in sync

Edit either representation. Changes flow both ways without reformatting what you wrote.

The OMG standard library

KerML foundations, SI units, ISQ quantities and the domain libraries, with autocomplete and hover docs.

Validation you can act on

Semantic checks and JSON Schema validation, reported where the problem is rather than as a wall of output.

Open formats

Export to JSON and OMG JSON-LD. Your models are not locked inside the tool.

How it works

Everything runs in the browser tab. There is no modelling server to install, and no round trip to a backend before you see a diagram.

Editor Monaco for text, a diagram canvas for structure — the same model behind both.
Parser Reads SysML v2 into a model and writes it back, preserving how you spelled it.
Std library The OMG libraries — KerML foundations, SI units, ISQ quantities — resolved for autocomplete and hover docs.
Validation Semantic checks and JSON Schema, reported against the line that caused them.
Export JSON, OMG JSON-LD and diagram images. Nothing is trapped in a proprietary file.

Examples

Each of these opens the editor with a model already loaded. Nothing to sign up for.

Beginner

Thermostat

Parts, attributes, ports and requirements on a system small enough to read in full.

Parametrics

Vehicle

ECU communication with mass and power budgets expressed as parametric constraints.

IoT

Smart home

Security, climate, lighting and energy management across one larger model.

 Requirements

Requirements blueprint

Requirements traced onto the structure that satisfies them.

 Behaviour

State machines

Behavioural modelling — states, transitions and their triggers.

 Multi-file

Homelab network

A model split across files, with imports resolved across them.

Roadmap

Three facts about how this got built, then what's ahead — not a commitment, the order and scope change. Items marked shared are engine work that lands in both SysML Online and UMStudio.io.

What's ahead — not committed Current plan — being built or being considered.
Oct 2025 Thesis began Build a working editor, not a paper about one
May 2026 Thesis Defence Submitted on v0.1.x — diagram, text, and a round-trip between them
Oct 2026 Online v0.7.0 — SysML v2, text and diagram, kept in sync
Being built

Deeper round-trip fidelity

Real-world SysML files, not just the examples, parse and re-serialize without losing what you wrote.

Being built

Real-time collaborative editingshared

More than one person in the same model at once.

Being built

Reference other notationsshared

Point a port at the timing diagram that defines its protocol, without leaving the SysML model.

Being considered

Requirements traceability reporting

Where a requirement is satisfied, and where it isn't yet.

Being considered

Simulation of state-machine behaviour

Step through states and transitions rather than only read them.

Being considered

Self-hosted deployment and SSOshared

For regulated environments where the model cannot leave the network.

Being considered

Visual regression as a release gateshared

So a diagram layout cannot silently drift across a release.

settled not committed
  1. Oct 2025 Thesis began Build a working editor, not a paper about one
  2. May 2026 Thesis Defence Submitted on v0.1.x — diagram, text, and a round-trip between them
  3. Oct 2026 Online v0.7.0 — SysML v2, text and diagram, kept in sync

What's ahead — not committed

Being built

Deeper round-trip fidelity

Real-world SysML files, not just the examples, parse and re-serialize without losing what you wrote.

Being built

Real-time collaborative editingshared

More than one person in the same model at once.

Being built

Reference other notationsshared

Point a port at the timing diagram that defines its protocol, without leaving the SysML model.

Being considered

Requirements traceability reporting

Where a requirement is satisfied, and where it isn't yet.

Being considered

Simulation of state-machine behaviour

Step through states and transitions rather than only read them.

Being considered

Self-hosted deployment and SSOshared

For regulated environments where the model cannot leave the network.

Being considered

Visual regression as a release gateshared

So a diagram layout cannot silently drift across a release.

The roadmap above is kept current as work lands, and alpha participants can see what is in flight from inside the product.

Need more than SysML?

UMStudio.io is the same engine with the other notations switched on — UML, BPMN, DCR, OLOG and WaveDrom timing diagrams — plus the cross-paradigm linking that connects them. SysML Online is the focused option; UMStudio.io is the workbench.

Everything marked shared above lands in both, because it is the same codebase underneath.

See UMStudio.io

Alpha adoption programme

The product is in alpha. It is not being sold yet, and there is nothing to pay for.

What joining means

You use it for real work, and tell us where it breaks. In exchange you get direct influence over what gets built, and early access as features land.

  • No cost, and no payment details taken
  • Expect rough edges — this is alpha, not a soft launch
  • Your feedback goes straight to the people building it
  • No commitment on either side; leave whenever it stops being useful

To take part, open the app and use Send feedback — it is in the toolbar, next to Help. Tell us what you are trying to model and what is getting in your way.

Open the app and tell us

Pricing

Not yet available. These figures are indicative, published early so you can judge whether the product will fit your budget later. Nothing here can be purchased, and no payment details are collected anywhere on this site.

Free

$0/month

Intended for learning and evaluation

  • A handful of projects
  • Local and browser storage
  • Open-format export
  • Community support

Pro

~$15/month

Intended for individual practitioners

  • Unlimited projects
  • Hosted storage and version history
  • Full export formats
  • Email support

Team

TBD

Intended for engineering teams

  • Shared projects
  • Real-time collaboration
  • Longer version history
  • Priority support

Self-hosted

TBD

Intended for regulated environments

  • Run it on your own infrastructure
  • SSO
  • Your data never leaves your network

Tiers, limits and figures will change before anything goes on sale. Alpha participants will be told well before that happens.