Diagram
Mermaid Diagram Renderer
Create flowcharts, sequences, class diagrams, state diagrams, ER diagrams, journeys, Gantt charts, Git graphs, mind maps, and timelines entirely in the browser.
How this tool works
Write Mermaid source, preview a sanitized diagram, and export SVG or PNG.
Large or hostile diagrams are rejected; exported diagrams still need human review for correctness and accessibility.
Examples
- Render an API request sequence.
- Export a deployment flowchart as SVG.
- Load a class-diagram template and export PNG.
Common use cases
Common mistakes
- Large or hostile diagrams are rejected; exported diagrams still need human review for correctness and accessibility.
- Validate the output in the system that will consume it.
- Use synthetic data when sharing debugging evidence.
Privacy and limitations
Processing is local to this browser tab. Device, extension, clipboard, and shared-screen risks still apply, so redact secrets before using any browser tool.
Representative valid workflow
Valid example
Render an API request sequence.
Expected: Use the tool output only after validating it in the receiving system.
Failure workflow
Invalid/failure example
Large or hostile diagrams are rejected; exported diagrams still need human review for correctness and accessibility.
QA checklist
- Exercise a valid input.
- Exercise malformed or unsupported input.
- Verify copy or download output.
- Confirm the input remains local during the interaction.
Documented limitation
Large or hostile diagrams are rejected; exported diagrams still need human review for correctness and accessibility.
Invalid or unsafe assumption
Invalid/failure example
A malformed edge or attempted script/HTML payload must produce an error or sanitized output without execution.
Mistakes to avoid
- Assuming a rendered diagram is factually correct.
- Embedding sensitive system names in an exported artifact.
- Using color alone to communicate state.
Limits of this workflow
Rendering is capped by source size, relationship count, and timeout.
PNG is rasterized from the current SVG and may be less accessible or scalable.
Local-processing and privacy boundary
Rendering is client-side; opt-in autosave stores only the Mermaid draft in localStorage and reset removes it.
Practical workflow
- Choose a template or write source.
- Resolve syntax errors and review the sanitized preview.
- Use zoom, pan, and fit for inspection.
- Export source plus SVG, and PNG only when raster output is required.
Official references
FAQ
Does the Mermaid Diagram Renderer upload my input?
No. The operation runs in the browser and does not send tool input to a DevPouch processing service.
What are the limits of the Mermaid Diagram Renderer?
Large or hostile diagrams are rejected; exported diagrams still need human review for correctness and accessibility.
Can Mermaid source run arbitrary HTML here?
No. Strict rendering disables HTML labels and the generated SVG is sanitized before display or export.