UtilityBaseDeveloper Tools
Mermaid Diagram Editor
Turn Mermaid text into live flowcharts, sequence, class, ER, and Gantt diagrams.
Updated July 14, 2026
How to use the mermaid diagram editor
- 1Write Mermaid syntax in the source pane, or load an example.
- 2Watch the diagram render live as you type.
- 3Pick a theme to restyle it.
- 4Export SVG or PNG, copy the SVG, or share a link.
Common uses
- Drawing a flowchart or sequence diagram for docs
- Adding a diagram to a README or Markdown file
- Sketching a database schema as an ER diagram
- Sharing an architecture diagram as a link
Frequently asked questions
What is Mermaid?
Mermaid is a popular open-source syntax for describing diagrams as text — you write a few lines like 'A --> B' and it draws the boxes and arrows for you. Because the diagram is plain text, you can keep it in version control, review changes in a pull request, and embed it in Markdown. GitHub, GitLab, Notion, and many docs tools render Mermaid natively, so a diagram you build here drops straight into them.
Which diagram types are supported?
The common Mermaid types: flowcharts, sequence diagrams, class diagrams, state diagrams, entity-relationship (ER) diagrams, Gantt charts, pie charts, and mind maps. Load an example for each to see the syntax, then edit it. If your syntax has an error, the editor keeps the last good diagram and shows the error message so you can fix it.
Can I export or share my diagram?
Yes. Export a scalable SVG or a high-resolution PNG (rendered at 2× for crisp output), or copy the raw SVG markup to paste elsewhere. Share copies a link that encodes your entire diagram source in the URL, so anyone who opens it sees exactly your diagram — nothing is stored on a server, and the whole tool runs in your browser.
About this tool
The Mermaid diagram editor renders diagrams from plain text, live, in your browser. Write in Mermaid's simple syntax on the left and watch the diagram build on the right — flowcharts, sequence diagrams, class and state diagrams, entity-relationship models, Gantt charts, pie charts, and mind maps. 'Diagram as code' means the diagram is text you can version-control, diff in a pull request, and paste straight into Markdown, a README, or GitHub (which renders Mermaid natively) — instead of dragging boxes in a drawing app. Pick a theme, then export a crisp SVG or PNG, copy the SVG markup, or share a link that encodes the whole diagram. It all runs locally — nothing is uploaded, no account, no watermark.
Like most tools on UtilityBase, the mermaid diagram editor runs entirely in your browser — nothing you enter is uploaded or stored on a server. It's free to use with no account required. Browse more developer tools here.
Was this tool helpful?
Related tools
Code Playground
A live HTML, CSS & JS editor with instant preview, console, and shareable links.
Developer Tools
Markdown Editor
Write markdown with a live preview — autosaved locally, HTML export included.
Text Tools
Venn Diagram Maker
Make a two-circle Venn diagram with editable labels and download it as a PNG.
Generators
JSON Formatter
Format, validate, and minify JSON with precise error locations.
Developer Tools
What Is My IP
Your public IP, and exactly what it reveals — location, ISP, timezone.
Developer Tools
Regex Tester
Test regular expressions live with match highlighting, groups, and a cheat sheet.
Developer Tools