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Mermaid Diagram Editor + Previewer

edit Mermaid diagram syntax with live SVG preview, zoom controls, fullscreen mode, and local draft persistence — supports all Mermaid diagram types (for an interactive pan/zoom flowchart canvas, see Interactive Mermaid Diagram)

About Mermaid Diagram Editor + Previewer

Mermaid Diagram Editor + Previewer lets you write Mermaid syntax and see the rendered SVG side-by-side. Works for every Mermaid diagram type — flowchart, sequence, class, ER, state, gantt, pie, journey, and more. For an interactive pan/zoom flowchart canvas with ELK-powered auto-layout, try Interactive Mermaid Diagram.

Use cases

Sketch architecture and sequence diagrams in Markdown-adjacent syntax without installing a graph editor.
Edit a Mermaid source and instantly see the SVG before pasting it into docs or a README.
Preview Mermaid diagrams that ship inside your existing Markdown content pipeline.

Examples

Render a top-down flowchart.

Input

flowchart TD
  A[Client] --> B[API]
  B --> C[(Database)]

Output

A Mermaid-rendered SVG showing the three nodes connected top-to-bottom.

Render a sequence diagram — supported here but not in Interactive Mermaid Diagram.

Input

sequenceDiagram
  Alice->>Bob: Hello
  Bob-->>Alice: Hi

Output

Mermaid renders the sequence diagram as SVG.

FAQ

How is this different from Interactive Mermaid Diagram?

This tool renders Mermaid's own SVG output and supports every Mermaid diagram type (sequence, gantt, class, ER, state, pie, journey, and more). Interactive Mermaid Diagram is flowchart-only but produces an interactive pan-zoom canvas using ELK.js layered layout and React Flow.

Does this work for non-flowchart diagrams?

Yes — any diagram type Mermaid can render is supported here, including sequence, class, ER, state, gantt, pie, and journey diagrams.

Where is my draft saved?

Drafts are stored in your browser's localStorage, scoped to this tool, so reloading keeps your latest source on the same device.