Free online MERMAID to SVG converter

What the MERMAID format is

In the mind-map and flowchart context, a MERMAID file is a plain-text source file containing Mermaid syntax, usually saved with the .mmd or .mermaid extension. The source describes flowcharts, sequence diagrams, class diagrams, state diagrams, entity-relationship diagrams, and mind maps rather than storing a finished image.

Mermaid files are created or edited in the Mermaid Live Editor, Visual Studio Code with a Mermaid extension, Obsidian, and documentation systems that support Mermaid blocks. Opening the file in a text editor shows declarations such as flowchart TD or mindmap; those declarations must be rendered by a Mermaid-compatible engine.

What the SVG format is

SVG, or Scalable Vector Graphics, is an XML-based image format that stores paths, shapes, and text. Browsers, documentation tools, vector editors, and many publishing applications can display it without a Mermaid runtime.

An SVG remains sharp when enlarged, generally scales better than a raster screenshot, and can be styled or edited in applications such as Inkscape. The exported file is the rendered diagram, not the original Mermaid source, so changing the diagram structure later is easier from the .mmd file.

How to convert MERMAID to SVG

Using Mermaid CLI

Mermaid CLI is the most direct desktop or command-line method and requires Node.js. Install the renderer with:

npm install -g @mermaid-js/mermaid-cli

Save the source as diagram.mmd, then render it with:

mmdc -i diagram.mmd -o diagram.svg

The -i option specifies the Mermaid source and -o specifies the SVG output. For a diagram that uses a custom theme or configuration file, pass it with:

mmdc -i diagram.mmd -o diagram.svg -c mermaid-config.json

You can also render directly with npx without a global installation:

npx -p @mermaid-js/mermaid-cli mmdc -i diagram.mmd -o diagram.svg

Using the Mermaid Live Editor

Open the source in the Mermaid Live Editor, check the rendered preview for syntax errors, then use Actions → Export Diagram → SVG or the equivalent SVG export control. Save the downloaded file with an .svg extension. This method is suitable when Node.js cannot be installed, but it depends on the editor's supported Mermaid version and available diagram features.

Using the built-in online converter

You can convert the file for free on 101convert.com without installing software: upload the .mmd or .mermaid file, choose SVG as the output format, start the conversion, and download the resulting .svg file.

Quality and compatibility considerations

Conversion errors usually come from unsupported Mermaid syntax, missing diagram dependencies, or invalid indentation in constructs such as mind maps. Render the source before exporting and inspect the SVG at its intended display size.

SVG output can depend on available fonts, browser rendering, Mermaid version, and theme settings. If exact appearance matters, use a common font or convert text to paths in a vector editor after export; converting text to paths makes later text editing more difficult.

Some SVG consumers restrict embedded styles, scripts, hyperlinks, or foreign XML elements. For maximum compatibility, use a plain static SVG and remove interactive features that depend on JavaScript. Keep the original Mermaid file alongside the SVG so the diagram remains structurally editable.