• 100% Free
  • No Sign-Up
  • No Credit Card
  • No Free Trial
  • No Pro Tier
  • No Watermarks

Nothing is uploaded. Just open it and start.

The Mermaid editor that stays out of your way

Write Mermaid, watch it render live, and ship the result — as a PNG in your docs, an SVG in your designs, or a link in your team chat. No sign-up, no watermarks, nothing between you and the diagram.

Instant live preview

The diagram re-renders as you type, with errors pinpointed on the exact line — never lose a working diagram to a typo.

PNG & SVG export

One click for a retina-sharp 2× PNG or an infinitely scalable SVG, with your diagram's fonts embedded.

Share with a link

Every share is an immutable snapshot with a short URL. Others can view it and fork their own copy — yours stays untouched.

Light & dark, beautifully

The editor and your diagrams re-theme together. Follows your system by default.

No account, no lock-in

Your work autosaves locally in your browser. Diagrams are plain Mermaid text you can take anywhere.

Start from a template

8 annotated examples — flowcharts, sequence diagrams, Gantt charts, and more.

Browse templates

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Frequently asked questions

What is Mermaid?
Mermaid is an open-source syntax for describing diagrams as plain text. You write a few lines of code — like `flowchart TD` followed by nodes and arrows — and it renders as a clean SVG diagram. Because diagrams are text, they diff, version, and copy-paste like code.
Is it free?
Yes. The editor, live preview, PNG/SVG export, and share links are free, with no account or sign-up required.
How do share links work?
Clicking Share saves an immutable snapshot of your diagram and gives you a short link. Anyone who opens it can view the diagram and edit their own copy — the original can never be changed or vandalized.
Can I export diagrams as images?
Yes — download any diagram as a crisp 2× PNG for docs and slides, or as an SVG that scales to any size. You can also copy the image straight to your clipboard.
Which diagram types are supported?
Everything Mermaid supports: flowcharts, sequence diagrams, class diagrams, state diagrams, entity-relationship diagrams, Gantt charts, pie charts, mindmaps, and more.