PlantUML Diagram Editor
Free online PlantUML editor. Write sequence, class, activity, use-case, and state diagrams with live preview, 20 built-in PlantUML themes, SVG/PNG export, shareable links, and local history. Encoding runs locally; the image renders on the public PlantUML server.
How to use
- Type PlantUML code; pick one of 20 themes and SVG/PNG.
- Render via preview (diagram source goes to the public PlantUML server; use Mermaid for fully local).
- Export the file; press Save to history for up to 30 local snapshots.
FAQ
Is rendering local?
Encoding runs locally, but the PNG/SVG itself renders on the public PlantUML server, so diagram source is sent for rendering. For fully offline diagrams use the Mermaid editor.
Which themes are available?
20 built-in !theme presets including amiga, hacker, minty, superhero, spacelab, and sketchy.
Where is history stored?
In this browser's localStorage, up to 30 snapshots — separate from the Mermaid history.