MacMD ViewerOffline Mermaid Viewer for Mac
Open a local .md file and MacMD Viewer renders its Mermaid diagrams fully offline. Read them in the app or press Space for Finder Quick Look. No plugin, browser upload, or editor required.
$19.99 one-time.
A Markdown viewer with Mermaid support
MacMD Viewer opens local .md files on Mac and renders their ```mermaid blocks inline, offline, both in the app and in Finder Quick Look. It is read-only: you write the Markdown in your editor and read the rendered diagrams here, for $19.99 once.
What your diagrams look like in MacMD Viewer
Why pay when free Mermaid viewers exist?
The free tools are good at what they do. mermaid.live and other web editors are the quickest way to paste and tweak one diagram, and VS Code renders Mermaid in its built-in Markdown preview since version 1.121, if you already have it open.
MacMD Viewer is for the moment in between: a local .md file you double-click in Finder, its diagrams rendered offline, or previewed with Space in Quick Look without opening an editor. Read-only, for $19.99 once.
Mermaid rendering without an internet connection
Mermaid rendering is bundled with the Mac app. Open Markdown from Finder, a project folder, or your editor's workspace and the fenced diagrams render locally. The file is not uploaded to a browser tool or converted on a remote server.
MacMD Viewer is intentionally read-only. Keep writing in Cursor, VS Code, Obsidian, or another editor; use this window for the rendered result. When the editor saves the file, the open document reloads automatically.
Six diagram types, all supported
Flowchart
Visualize processes and decision trees with directional graphs.
Mermaid source
```mermaid
graph TD
A[Start] --> B{Decision}
B -->|Yes| C[Action 1]
B -->|No| D[Action 2]
C --> E[End]
D --> E
```Sequence Diagram
Show interactions between components over time.
Mermaid source
```mermaid
sequenceDiagram
Client->>Server: HTTP Request
Server->>Database: Query
Database-->>Server: Results
Server-->>Client: JSON Response
```State Diagram
Model state machines and transitions.
Mermaid source
```mermaid
stateDiagram-v2
[*] --> Idle
Idle --> Loading: fetch()
Loading --> Success: 200 OK
Loading --> Error: 4xx/5xx
Error --> Idle: retry()
Success --> [*]
```Gantt Chart
Plan project timelines and task dependencies.
Mermaid source
```mermaid
gantt
title Project Plan
section Design
Wireframes :a1, 2024-01-01, 7d
Mockups :a2, after a1, 5d
section Dev
Frontend :b1, after a2, 14d
Backend :b2, after a2, 10d
```Pie Chart
Display proportional data in a circular chart.
Mermaid source
```mermaid
pie title Languages Used
"Swift" : 45
"TypeScript" : 30
"Python" : 15
"Other" : 10
```Class Diagram
Document object-oriented structures and relationships.
Mermaid source
```mermaid
classDiagram
class Document {
+String title
+String content
+render() HTML
}
class Renderer {
+parse(md) AST
+toHTML(ast) HTML
}
Document --> Renderer
```Just write Mermaid, we handle the rest
Use a standard fenced code block with the mermaid language tag. MacMD Viewer detects it automatically and renders the diagram inline. No configuration files, no setup, no extensions to install.
Mermaid on Mac: common questions
Is MacMD Viewer a Markdown viewer with Mermaid support?
Yes. MacMD Viewer is a read-only Markdown viewer for Mac that renders ```mermaid code blocks inline and offline, in the app and in Finder Quick Look. Mermaid support is built in, with no plugin or extension.
What Mermaid diagram types does MacMD Viewer support?
Flowcharts, sequence diagrams, state diagrams, Gantt charts, pie charts, and class diagrams. All standard Mermaid syntax is rendered inline from fenced ```mermaid code blocks.
Do I need a plugin or extension to render Mermaid?
No. MacMD Viewer detects ```mermaid fenced code blocks automatically and renders them inline. There are no configuration files, no extensions, and no setup to install.
Does MacMD Viewer render Mermaid diagrams fully offline?
Yes. Mermaid rendering is bundled with the Mac app, so local .md files render without an internet connection or a browser upload. The rendering itself makes no network request.
Is MacMD Viewer an offline Mermaid editor?
No. It is a read-only Mermaid viewer for Markdown files. Write or edit the source in Cursor, VS Code, Obsidian, or another editor, then use MacMD Viewer to read the rendered diagram in the app or Finder Quick Look.
Can MacMD Viewer render Mermaid diagrams that Claude or ChatGPT generate?
Yes. When an AI agent writes a Mermaid diagram into a .md file, MacMD Viewer renders it inline the moment you open or save the file — no pushing to GitHub to check whether it renders.
Can I preview Mermaid diagrams in Finder with QuickLook?
Yes. With the QuickLook extension, press Space on a .md file in Finder and Mermaid diagrams render in the preview without opening the app.
How do I write a Mermaid diagram in Markdown?
Use a fenced code block with the mermaid language tag and standard Mermaid syntax inside it. MacMD Viewer detects the tag and renders the diagram automatically.
Is Mermaid support included in the $19.99 price?
Yes. Mermaid rendering is built into MacMD Viewer at the one-time $19.99 price — no subscription and no add-on.
Diagrams are just the start
Syntax highlighting, QuickLook, live reload, and more.