PlantUML Generator
DiagramsWrite PlantUML markup for class, sequence, activity, component, and state diagrams and preview them instantly. Export to SVG or PNG with one click — no installation needed.
Diagrams are rendered by the free public PlantUML server (plantuml.com). Your diagram source is sent to that server over HTTPS — do not include sensitive or confidential information. No data is stored by this site. PlantUML is open-source software licensed under the GPL v3. Syntax guide →
About PlantUML Generator
The PlantUML Generator is a browser-based PlantUML editor that renders diagrams in real time as you type. Author class diagrams with inheritance and interfaces, sequence diagrams with actors and activation bars, activity diagrams with swimlanes, component diagrams showing system boundaries, or state machine diagrams — all without installing Java or PlantUML locally. The split-pane interface keeps your markup on the left and the rendered diagram on the right so you can iterate quickly. Snippet templates for every diagram type are included to get you started in seconds.
Features
- ✓Supports class, sequence, activity, component, state, and use case diagram types
- ✓Real-time rendering — diagram updates as you type with debounce for smooth performance
- ✓3-column layout: code editor | render button | live preview
- ✓Examples dropdown with 6 ready-made diagrams for every supported type
- ✓Zoom in/out from 30% to 200% with a one-click reset
- ✓Background picker: auto (theme-aware), transparent, or custom color — applied to PNG exports
- ✓Export rendered diagram as SVG or PNG (2× retina, with selected background)
- ✓Shareable URL — click Share to copy a link that restores your exact diagram
- ✓Copy source button to grab PlantUML markup for use in Confluence, Notion, or GitHub
- ✓Docs link to the official PlantUML syntax guide
Common Use Cases
- Drafting UML class diagrams for code review or design documentation
- Sketching system interaction flows with sequence or component diagrams
- Producing activity diagrams for business process documentation
- Creating state machine diagrams for protocol or UI flow specification
- Embedding PlantUML exports in Confluence, Notion, or GitHub wiki pages
Frequently Asked Questions
QDo I need to install PlantUML or Java on my machine?
No. The tool sends your encoded markup to the public plantuml.com rendering server, so no local Java or PlantUML installation is required. Only the encoded diagram text leaves the browser.
QCan I use `!include` or external theme files?
External `!include` directives referencing local file paths are not supported in the browser environment. You can paste the contents of include files directly into the editor.
QHow do I share a diagram with a colleague?
Click the Share icon in the preview toolbar to copy a URL with your PlantUML markup encoded in the query string. Anyone with the link opens the exact same diagram in the editor.
QWhat is the maximum diagram complexity supported?
PlantUML can produce very large diagrams. Rendering time scales with complexity — extremely large diagrams with hundreds of elements may take a few seconds. There is no hard element limit.