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Overview

Apollon is an open-source UML and modeling editor for the web. You draw diagrams in the browser, collaborate in real time, and export to SVG, PNG, PDF, or JSON. There is nothing to install to get started.

What you can draw​

Apollon supports 13 diagram types:

  • Class
  • Object
  • Activity
  • Use Case
  • Communication
  • Component
  • Deployment
  • Petri Net
  • Reachability Graph
  • Syntax Tree
  • Flowchart
  • BPMN
  • SFC

Any diagram exports to SVG, PNG, PDF, or JSON. JSON round-trips — re-import it to keep editing. Real-time collaboration is optional and runs over WebSockets.

Which way to use Apollon​

Apollon ships in three forms. Pick the one that matches your context.

Hosted web app​

Open apollon.aet.cit.tum.de and start drawing. No install, no account. Diagrams persist in your browser and can be shared by URL. Use this when you want to draw and share a diagram with no install.

VS Code extension​

Install the extension if you want diagrams to live next to your code. It stores each diagram as a plain .apollon file in your repository, so diagrams are versioned and reviewed like any other source.

Embeddable library​

@tumaet/apollon is published on npm. Embed the editor in your own product when you need UML modeling inside an existing application.

npm install @tumaet/apollon react react-dom @xyflow/react yjs y-protocols
You want to...Use this
Draw a diagram right now, share it by URLHosted web app
Keep diagrams in version control with your codeVS Code extension
Add a UML editor to your own applicationEmbeddable library

Next steps​

  • Get Apollon — set up the hosted app, the VS Code extension, or a self-hosted instance.
  • Library docs — the embedding API for @tumaet/apollon.
  • Contributor docs — build Apollon from source and contribute.