Frequently Asked Questions

What is yUML?

yUML is an online tool for creating diagrams from simple text. Describe your diagram in a URL or API call, and yUML renders it as SVG or PNG. No desktop software, no drag-and-drop — just text in, diagram out.

Is it free?

Yes. The rendering API is free with generous rate limits. The Playground is also free to use. Pro plans are available for higher limits and additional features.

What diagram types are supported?

Class, activity, use case, sequence, state, journey map, roadmap, and timeline. See the diagram types documentation for syntax details.

Can I embed diagrams in my website or app?

Absolutely — that's what yUML is built for. Use an <img> tag with a yUML URL, or call the POST API from your backend. See the quick start guide.

Why should I use yUML over a desktop tool?

yUML saves time. No software to install, no files to manage, no layout fiddling. Write the text, get the diagram. It's designed for quick, lightweight diagrams in documentation, blogs, and communication — not full-spec UML modelling.

What about special characters?

URL-encode characters like # (%23) and ; (%3B). Or use the POST API where the DSL is in JSON and doesn't need URL encoding.

Where can I get help?

Check the documentation for syntax reference and API details. For questions and feedback, visit the community forum on GitHub.