Mermaid Viewer Online

Paste Mermaid code and see the rendered diagram

Paste markdown below or use example: , ,

See the diagram, not the code

Mermaid diagrams are written as text, so they travel well: an AI assistant can generate one, a pull request can diff one, and a README can carry one. The catch is that text is all you get until something renders it. This Mermaid viewer turns the code into the diagram in your browser, with nothing to install.

Put the diagram in a fenced code block tagged mermaid and render it. Flowcharts, sequence diagrams, class and state diagrams, entity-relationship diagrams, Gantt charts, timelines, mind maps, and pie and bar charts all render from the same box. The surrounding Markdown renders too, so a diagram can stay next to the paragraphs that explain it.

Large diagrams are the reason a dedicated viewer matters. An architecture diagram with forty nodes is unreadable at page width, so each rendered diagram has zoom, pan, and a fullscreen mode, and can be exported as SVG or PNG for a slide, a ticket, or a design document.

Pasted code and local files render in the browser. Nothing is published unless you explicitly create a share link, which makes the viewer suitable for a quick look at a diagram from an internal document.

How to view a Mermaid diagram online

  1. Paste your Mermaid code into the box above, inside a fenced block that starts with ```mermaid — or replace the code in the sample.
  2. Hit Render it → to draw the diagram. A Markdown file that already contains Mermaid blocks can be opened or dropped in as it is.
  3. Zoom, pan, or open the diagram fullscreen, then export it as SVG or PNG if you need the image.

Built for reading real diagrams

A viewer for diagrams that are too large, too many, or too broken for a basic preview.

Diagram types

  • Flowcharts and subgraphs
  • Sequence, class, and state diagrams
  • Entity-relationship diagrams
  • Gantt charts, timelines, and mind maps
  • Pie charts and XY bar and line charts

Inspect and export

  • Zoom and pan inside each diagram
  • Fullscreen mode for dense architecture diagrams
  • Export a diagram as SVG or PNG
  • Several diagrams in one document

When the code is broken

  • Syntax errors are reported per diagram
  • Quick Fix repairs common mistakes in AI-generated Mermaid
  • The rest of the document still renders
  • Mermaid Studio for editing with a live preview

View your Mermaid diagram now

FAQ

Is the Mermaid viewer free?

Yes — viewing Mermaid diagrams is free and works without an account.

How do I view a Mermaid diagram online?

Paste the Mermaid code inside a fenced block tagged mermaid, then render it. If you already have a Markdown file with Mermaid blocks, open the file and every diagram renders in place.

Can I open a .mmd file?

A .mmd file holds bare Mermaid code with no fence. Paste its contents between a ```mermaid line and a closing ``` line and it renders like any other diagram.

Which Mermaid diagram types are supported?

Flowcharts, sequence, class, state, and entity-relationship diagrams, Gantt charts, timelines, mind maps, pie charts, and XY charts, along with the other diagram types included in current Mermaid.

Can I export a Mermaid diagram as an image?

Yes. Each rendered diagram can be exported as SVG or PNG. SVG stays sharp at any size, which suits slides and printed documents.

Why does my Mermaid diagram not render?

Usually a syntax error: an unquoted label with brackets or parentheses, a missing arrow, or a diagram type the code does not declare. The viewer reports the failing diagram, and Quick Fix can repair common mistakes.

Is my diagram uploaded?

No — pasted code and opened files render in your browser. Content only leaves your device if you explicitly create a share link.

What is the difference between the Mermaid viewer and Mermaid Studio?

The viewer is for reading: paste or open, then inspect and export. Mermaid Studio is for working on one diagram, with an editor and a live preview side by side.

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