Text & Docs
Mermaid Editor
Mermaid Editor online tool for writing Mermaid source locally, previewing flowcharts, sequence diagrams, and class diagrams, and exporting PNG or SVG.
About this tool
Mermaid Editor keeps source editing, template switching, and live diagram preview in the same workspace for fast flowchart, sequence, class, and state diagram drafting.
This version renders directly in the browser with the local Mermaid runtime, so it does not rely on a third-party diagram service and fits privacy-sensitive documentation workflows.
Best use cases
- Add lightweight diagrams to architecture notes, API docs, and knowledge base pages while checking node relationships immediately.
- Create sequence or state diagrams quickly for pull requests, technical reviews, or weekly project updates without switching to separate desktop software.
- Clean up Mermaid drafts here, then continue into Markdown, PlantUML, or text tools to finish the delivery flow.
How to use it
- Pick a template or paste Mermaid source and edit it in the left-side workspace.
- Press Render or use the shortcut to refresh the preview and verify layout and connections.
- Export PNG or SVG when ready, or copy the source for your docs and repositories.
FAQ
Does Mermaid Editor upload my data?
Unless the page explicitly says a network request is required, the main workflow runs locally in your browser.
When should I use Mermaid Editor?
Use it when you need cleaned and reusable output for quick edits, structure fixes, and content review.
What should I prepare before using Mermaid Editor?
Usually you only need the draft content, structured text, or source snippets and a clear idea of what output you want to verify or reuse next.