Mermaid diagram generator
A fast, private Mermaid live editor. Paste any Mermaid diagram and see it render instantly — flowcharts, sequence diagrams, ER models, class diagrams, gantt charts and mind maps all in one place.
One step per line. Indent two spaces to branch beneath the line above.
What is Mermaid?
Mermaid is an open-source “diagram-as-code” language: you write a short text description and Mermaid renders the diagram. It is the same syntax GitHub, GitLab, Obsidian and many docs platforms render natively, which is why a Mermaid diagram is so portable — paste the block anywhere that supports it and it draws itself.
This editor runs the official Mermaid renderer in your browser. Type or paste any supported diagram type and it renders live, with zero setup and nothing sent to a server.
From editor to your docs
Export a vector SVG for crisp embedding, a PNG for slides, or copy a ready-made ```mermaid Markdown block to drop into a GitHub README where it renders automatically. For diagrams that should stay editable, keep them as Mermaid source in your repo and re-open them here any time.
Frequently asked questions
Is this a free online Mermaid editor?
Yes — paste Mermaid and it renders live in your browser, free, with no signup and no watermark. You can export SVG/PNG or copy the source.
Which Mermaid diagram types are supported?
Flowcharts, sequence diagrams, ER diagrams, class diagrams, state diagrams, gantt charts, mind maps and pie charts — the full Mermaid renderer is loaded.
Does my Mermaid code get uploaded?
No. The Mermaid engine loads once from a public CDN and then everything renders locally. Your diagram text never leaves your device.
How do I embed a Mermaid diagram in a GitHub README?
Copy the Markdown block from the export menu and paste it into your README. GitHub renders fenced ```mermaid code blocks automatically — no image needed.
Which Mermaid version is this?
The editor loads Mermaid 11 from a public CDN, so you get current syntax and diagram types without installing anything.