Mermaid Diagram Renderer
Render Mermaid diagrams in your browser — flowcharts, sequence, class, state, Gantt, pie, ER, and user journey diagrams. 100% client-side, no server.
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What is Mermaid Diagram Renderer?
The Mermaid Diagram Renderer turns Mermaid markdown into visual diagrams entirely in your browser. Mermaid is a text-based diagramming language that lets you describe flowcharts, sequence diagrams, class diagrams, state diagrams, Gantt charts, pie charts, entity-relationship diagrams, and user journey maps using simple, code-like syntax. Type your definition into the editor and the renderer produces a live SVG preview with light/dark theme support. You can copy the SVG markup or download the diagram as an SVG or high-resolution PNG — all 100% client-side with no server uploads.
Key Benefits
- 100% client-side: your diagram code is rendered in the browser and never uploaded to any server
- Supports eight diagram types including flowchart, sequence, class, state, Gantt, pie, ER, and user journey
- Live preview that re-renders as you type with helpful syntax-error messages
- Light and dark themes with automatic site-theme detection
- One-click export to SVG markup, SVG file, or high-resolution PNG
Common Use Cases
- •Documenting system architecture and data flow for engineering wikis and README files
- •Designing sequence and class diagrams during API and database planning
- •Building Gantt charts and project timelines for sprint planning
- •Creating user journey maps for product and UX research
- •Drafting flowcharts for Standard Operating Procedures and decision trees
How to Use the Mermaid Diagram Renderer
- Write or paste Mermaid code: Enter your Mermaid diagram definition in the code box. You can also load an example preset from the dropdown.
- Pick a theme: Switch between Light and Dark themes to match your preference or the site theme.
- Review the live preview: The diagram renders automatically as you type. If there is a syntax error, the error message appears below the editor.
- Copy or download: Copy the SVG to your clipboard, or download the diagram as an SVG or PNG file for use in docs and slides.
Key Features
- Live preview that re-renders as you type with a 500ms debounce
- Supports flowchart, sequence, class, state, Gantt, pie, ER, and user journey diagrams
- One-click example presets for all eight diagram types
- Light and dark themes with automatic site-theme detection
- Export the rendered diagram as SVG or high-resolution PNG
- 100% client-side rendering — your code never leaves the browser
Frequently Asked Questions
What diagram types does the Mermaid Diagram Renderer support?
It supports all major Mermaid diagram types: flowchart, sequence, class, state, Gantt, pie, entity-relationship (ER), and user journey diagrams. Use the Example Diagram dropdown to load a ready-made template for each type.
Is my diagram code sent to a server?
No. The Mermaid library is bundled and runs entirely in your browser. Your diagram code is never uploaded to any server, which makes the tool safe for proprietary architecture diagrams and confidential workflows.
Can I export the rendered diagram?
Yes. You can copy the raw SVG markup to your clipboard, download the diagram as an SVG file, or download a high-resolution (2x) PNG file. SVG is best for docs and wikis; PNG works well for slides and chat apps.
Why does the preview show an error?
Mermaid reports a syntax error if your diagram definition is malformed — for example a missing arrow, an unclosed node label, or an unsupported directive. The error message is shown beneath the editor with the line number so you can fix it quickly.