Free browser tool
Mermaid Editor Online
Paste Mermaid code, edit it in your browser, and see the diagram update live. No sign-up, no watermark, and no code is sent to an AI service.
Free · No sign-up · Runs in your browser
Have an idea?Let AI sketch itMermaid code
Paste or write Mermaid code. The preview updates as you type.
Your Mermaid code is rendered locally in this browser. It is not sent to an AI service.
Live preview
Your Mermaid diagram will appear here.
What is a Mermaid editor?
A Mermaid editor lets you write diagram code and see the result immediately. It is useful for flowcharts, sequence diagrams, entity relationship diagrams, class diagrams, state diagrams, mind maps, and more.
How to use the Mermaid editor
- 1
Paste Mermaid code
Start with a diagram declaration such as flowchart TD or sequenceDiagram.
- 2
Edit and preview
Change labels, nodes, and connections. The preview refreshes automatically as you type.
- 3
Export your diagram
Copy the code or download the finished diagram as SVG or PNG, without a watermark.
Supported Mermaid diagram types
The editor supports flowcharts, sequence diagrams, class diagrams, state diagrams, ER diagrams, user journeys, Gantt charts, pie charts, mind maps, timelines, quadrant charts, Git graphs, Sankey diagrams, Ishikawa diagrams, architecture diagrams, XY charts, and treemaps.
Mermaid editor FAQ
Is this Mermaid editor free?
Yes. The Mermaid editor is free to use without an account. Rendering happens in your browser, and SVG and PNG exports are free without a watermark.
Can I paste Mermaid code directly?
Yes. Paste Mermaid code into the editor and the preview will update automatically. The first line should identify the diagram type, such as flowchart TD or sequenceDiagram.
Is my Mermaid code uploaded?
No. This tool renders Mermaid code locally in your browser. It does not send the code to an AI service or require an account.
Can I export the diagram?
Yes. You can copy the Mermaid code or download the rendered diagram as SVG or PNG.
Built with Mermaid · Mermaid