When Claude or ChatGPT drops a flowchart into a .md answer, MacMD Viewer renders it inline. Standard Mermaid syntax in a fenced code block. No plugins, no pushing to GitHub to preview.
Visualize processes and decision trees with directional graphs.
```mermaid
graph TD
A[Start] --> B{Decision}
B -->|Yes| C[Action 1]
B -->|No| D[Action 2]
C --> E[End]
D --> E
```Show interactions between components over time.
```mermaid
sequenceDiagram
Client->>Server: HTTP Request
Server->>Database: Query
Database-->>Server: Results
Server-->>Client: JSON Response
```Model state machines and transitions.
```mermaid
stateDiagram-v2
[*] --> Idle
Idle --> Loading: fetch()
Loading --> Success: 200 OK
Loading --> Error: 4xx/5xx
Error --> Idle: retry()
Success --> [*]
```Plan project timelines and task dependencies.
```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
```Display proportional data in a circular chart.
```mermaid
pie title Languages Used
"Swift" : 45
"TypeScript" : 30
"Python" : 15
"Other" : 10
```Document object-oriented structures and relationships.
```mermaid
classDiagram
class Document {
+String title
+String content
+render() HTML
}
class Renderer {
+parse(md) AST
+toHTML(ast) HTML
}
Document --> Renderer
```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.
Flowcharts, sequence diagrams, state diagrams, Gantt charts, pie charts, and class diagrams. All standard Mermaid syntax is rendered inline from fenced ```mermaid code blocks.
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.
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.
Yes. With the QuickLook extension, press Space on a .md file in Finder and Mermaid diagrams render in the preview without opening the app.
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.
Yes. Mermaid rendering is built into MacMD Viewer at the one-time $19.99 price — no subscription and no add-on.
Syntax highlighting, QuickLook, live reload, and more.