Simple PlantUML

Editor and viewer for PlantUML diagrams, right in the browser. No backend: the diagram text is encoded and sent as part of the URL to PlantUML's public server, which returns the rendered image.

Features

• Editor with syntax highlighting (CodeMirror)
• Automatic preview (debounced) as you type
• Local persistence of what you wrote
• Shareable link
• Download the diagram as SVG or PNG
• Light/dark theme
• Ready-made examples (sequence, classes, use cases)
• Resizable split between editor and preview
• Zoom and pan on the preview (fit, 100%, +/-, mouse wheel, drag)
• Toggleable line wrap in the editor

Running locally

No build, no dependencies to install. Just serve the static files:

python3 -m http.server 8000

And open http://localhost:8000.

If you're on WSL, localhost is automatically forwarded to the Windows browser.

Deploying to GitHub Pages

1. Create the repository on GitHub and push the main branch.
2. In the repository settings: Settings > Pages > Build and deployment > Source: Deploy from a branch, select the main branch and the / (root) folder.
3. The site becomes available at https://<user>.github.io/<repo>/.