Documentation

Getting Started

Open Markdown is a native macOS app for reading Markdown files. Open any .md file and it renders instantly with GitHub-style formatting.

There are several ways to open a file:

Live Reload

When a file is open, Open Markdown watches it for changes. Edit the file in any text editor and the preview updates automatically — no manual refresh needed.

Changed sections are briefly highlighted so you can see exactly what was modified.

Multi-Window

Press Cmd+N to open a new window and view multiple files side by side. Each window independently tracks and live-reloads its own file.

Keyboard Shortcuts

Shortcut Action
Cmd+OOpen file
Cmd+NNew window
Cmd+FFind in page
Cmd+TToggle light/dark theme
Cmd+=Zoom in
Cmd+-Zoom out
Cmd+0Reset zoom
Cmd+WClose window

Supported Formats

Open Markdown recognises files with the following extensions:

File Associations

To double-click a Markdown file and have it open in Open Markdown, you need to set it as the default app:

Via System Settings (macOS 14+):

  1. Open System Settings → Default Apps
  2. Set Open Markdown as the default for Markdown files

Via Finder:

  1. Right-click any .md file in Finder
  2. Select Get Info
  3. Under Open with, choose Open Markdown
  4. Click Change All... to apply to all files of this type

Mermaid Diagrams

Fenced code blocks with the mermaid language tag are automatically rendered as diagrams:

Supported diagram types include flowcharts, sequence diagrams, class diagrams, state diagrams, Gantt charts, pie charts, and more. See the Mermaid documentation for the full list.

Syntax Highlighting

Code blocks with a language tag are syntax-highlighted using highlight.js, which supports 190+ languages. The highlighting theme automatically adapts to light and dark mode.

Export & Copy