Are my Mermaid files uploaded?

No. Diagrams you open from your device stay on your device and are rendered locally with Mermaid.js. Only the public sample diagram is requested from the server.

What diagram types does Mermaid support?

Mermaid supports flowcharts, sequence diagrams, class diagrams, state diagrams, entity relationship diagrams, Gantt charts, pie charts, journey maps, mind maps and timelines — all from text syntax.

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Q: What is a Mermaid file?

Mermaid (.mermaid, .mmd) is a text-based diagramming format that uses simple markdown-like syntax to generate flowcharts, sequence diagrams, Gantt charts, class diagrams, state diagrams and more. It is supported natively by GitHub, GitLab, Notion and many documentation tools.

Free online Mermaid viewer. Open and preview Mermaid diagrams (.mermaid, .mmd) directly in your browser — no upload, no software.

.mermaid.mmd

Sample Mermaid Diagram

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Tool usage guide

About this file format

Mermaid (.mermaid, .mmd) is a text-based diagramming language created by Knut Sveidqvist in 2014. Instead of drawing shapes manually, you write diagram structure as simple text syntax (similar to Markdown), and Mermaid.js renders it into visual diagrams. It supports flowcharts, sequence diagrams, Gantt charts, class diagrams, state diagrams and more. Mermaid is built into GitHub, GitLab, Notion, Obsidian and many documentation platforms, making it the most widely adopted 'diagrams-as-code' tool.

Mermaid Viewer

About this file format

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