Mermaid Editor
Edit Mermaid diagrams with live preview and export SVG or PNG.
Mermaid turns plain text into professional diagrams, which makes it ideal for README files, architecture docs, and design reviews. Utilitoo's Mermaid Editor pairs a code panel on the left with a live preview on the right so you can iterate on flowcharts, sequence diagrams, class diagrams, and Gantt charts without switching tools.
Developers paste Mermaid blocks from GitHub or Notion to fix syntax errors before merging, technical writers preview documentation diagrams, and teams export SVG assets for wikis or PNG slides for stakeholder meetings. The preview updates as you type and respects your light or dark site theme automatically.
Use Copy to grab your Mermaid source, Export SVG for crisp scalable graphics, or Export PNG when you need a raster image for presentations.
Everything renders locally in your browser on Utilitoo. Your diagram code and exports are never uploaded to any server. Free, fast, and privacy-first for developers, writers, and product teams who diagram in code.
Live preview follows your site theme. Toggle light/dark mode from the header.
Diagram preview will appear here…
How to use
- Write or paste Mermaid code in the left editor panel.
- Watch the diagram render live in the preview on the right.
- Copy code or export SVG/PNG when your diagram is ready.
Frequently Asked Questions
How do I edit Mermaid diagrams online for free?▼
Paste or write Mermaid code in Utilitoo's left panel. The live preview on the right renders your diagram instantly with no account required.
Can I export Mermaid diagrams as SVG or PNG?▼
Yes. Utilitoo provides Export SVG and Export PNG buttons that download your current rendered diagram directly to your device.
Does the Mermaid editor work in dark mode?▼
Yes. Toggle light or dark mode from the site header and the diagram preview updates to match your theme.
Which Mermaid diagram types can I create?▼
Utilitoo supports flowcharts, sequence diagrams, class diagrams, state diagrams, ER diagrams, Gantt charts, and other common Mermaid syntax.
Is my Mermaid code sent to a server?▼
No. Utilitoo renders Mermaid entirely in your browser. Your source code and exports stay on your device.
Related Tools
Markdown Viewer
Preview Markdown as formatted HTML in real time.
YAML Formatter
Format and validate YAML configuration files.
JSON Formatter
Format and beautify JSON online instantly.
Diff Checker
Compare two texts and highlight differences.
CSV Viewer
View and inspect CSV data in a table.
SQL Formatter
Format and beautify SQL queries.