Privacy Policy

Last updated: September 2, 2026

mermaid.design (“we”, “our”, or “the site”) is a free online Mermaid diagram editor. This Privacy Policy explains what data we handle and how.

Client-Side Processing

All diagram editing and rendering happens entirely in your browser. The Mermaid code you type and the diagrams you create are processed locally on your device and are never transmitted to our servers.

Local Storage

The site uses your browser’s local storage to remember your work and preferences between visits, including:

• Your current diagram code
• The selected diagram theme and render settings
• Export format and resolution preferences
• Preview zoom level

This data stays on your device. You can clear it at any time through your browser settings.

Data We Do Not Collect

• We do not require accounts or sign-ups
• We do not collect, store, or transmit your diagram content
• We do not use tracking cookies

Third-Party Services

The “Help” button links to the Mermaid documentation website (mermaid.js.org), which is operated by a third party and governed by its own privacy policy.

Changes to This Policy

We may update this Privacy Policy from time to time. Changes will be posted on this page with an updated revision date.

Contact

If you have questions about this Privacy Policy, contact us at [email protected].