Privacy Policy

Last updated: August 14, 2026

UML Diagram Studio (umldiagram.app) is a free online UML diagram tool. This page explains what we collect and how we use it.

Diagrams you create

Diagram code you type in the editor is stored in your browser (localStorage) so your work can persist on that device. We do not require an account to use the tool.

AI assistant

If you use the AI chat, your prompts are sent to our API so a language model can generate PlantUML or related help. Do not paste secrets, passwords, or personal data into the assistant.

Email newsletter

If you subscribe in the footer, we store the email address you submit so we can send product and tutorial updates. You can unsubscribe using the link in those emails or by writing to contact@umldiagram.app.

Analytics and ads

The site may load Google Analytics and Google AdSense. Those services can set cookies and collect usage data according to Google's policies.

Contact

Questions: contact page or contact@umldiagram.app.