Mermaid Live — a browser editor with live preview and beautify
A Mermaid live editor that renders as you type, with the same paste-and-preview flow you expect — plus a one-click beautify step and clean SVG / PNG export. No account, no install. The Mermaid source stays exactly as you wrote it.
Inside the editor
The live-preview loop is the baseline. What you actually get on top of it:
Source on the left, live preview on the right. Every keystroke re-renders — no save button, no manual refresh. Syntax errors surface inline the moment you type them.
Re-lays out flowchart, sequence, state, class, ER, and Gantt diagrams so the main path, branches, loops, and merges read at a glance. The preview updates in place.
Switch between presentation themes built for docs, slides, and reviews. The Mermaid source stays exactly as you wrote it; only the visual layer changes.
Click any node or edge in the preview to change background, border, line color, width, and text color from a floating toolbar — no source edits required.
Draft a Mermaid diagram from a short prompt, or run existing source through AI refine for cleaner labels and structure. Output drops into the live preview.
Export SVG with fonts inlined the moment the preview looks right. Pro adds 4× HD PNG sized for decks and printed handouts — watermark-free.
When to use a Mermaid live editor
Quickly verify a snippet parses and renders. Live preview flags syntax issues the instant you type them.
Live preview plus one-click beautify is faster than tweaking layout by hand inside a default Mermaid renderer.
Live preview the result, switch themes, and export HD PNG sized for slides — without leaving the editor.
If you only need to verify syntax renders, the official mermaid.live is the most direct option. Use this Mermaid live editor when the diagram is going somewhere people will read it. See the full side-by-side at /comparison/mermaid-live-alternative.
Frequently asked questions
Is this a Mermaid live editor?
Yes. It is a Mermaid live editor that runs in the browser — paste Mermaid source on the left, the live preview re-renders on the right as you type, then beautify or export without leaving the page.
How does this compare to mermaid.live?
Same live preview feedback loop. The difference is the one-click beautify step, theme switching, and HD PNG export. See the full side-by-side at /comparison/mermaid-live-alternative.
Do I need an account to use the Mermaid live editor?
No. Anonymous preview, beautify, and export to SVG or PNG are free. An account is only needed to save Mermaid diagrams to the cloud and generate share links.
Does the live preview support every Mermaid diagram type?
Flowchart, sequence, state, class, ER, and Gantt all render live with one-click beautify. Other Mermaid grammars also render live with default styling and will gain bespoke beautification in later releases.
Can I open the Mermaid live editor offline?
The live editor runs in the browser, so an internet connection is needed to load it. Once loaded, paste, preview, and beautify happen client-side; export to SVG or PNG also runs without a round trip.
Open the Mermaid live editor
Paste your Mermaid source and see the live preview render instantly. Beautify, switch themes, and export when ready.