OpenMarkdownReader

Homepage: wikihub.md/openmarkdownreader

A beautiful, open-source Markdown file reader and editor for Mac built with Electron.

Features

• Clean, GitHub-style markdown rendering
• Syntax highlighting for code blocks
• Dark mode support (follows system preference)
• Drag and drop file support
• Native Mac title bar with traffic lights
• Multi-tab and multi-window support
• Edit mode with live preview toggle (⌘E)
• File browser sidebar with folder navigation
• Remote folder browsing and guarded remote saves over HTTP(S), including Tailscale URLs
• Adjustable content width
• GFM (GitHub Flavored Markdown) support including:
  • Tables
  • Task lists
  • Strikethrough
  • Autolinks

Running

npm start

Keyboard Shortcuts

• ⌘O - Open file
• ⌘T - New tab
• ⌘W - Close tab
• ⌘E - Toggle edit mode
• ⌘S - Save
• ⇧⌘S - Save As / save a local copy of a remote file
• ⌘B - Toggle sidebar
• Escape - Cancel/revert edits
• Ctrl+Tab - Next tab
• Ctrl+Shift+Tab - Previous tab

Usage

1. Open a file: Click "Open File" or press ⌘O
2. Drag and drop: Drop a .md file onto the window
3. Edit: Press ⌘E to toggle edit mode
4. Browse folders: Click the sidebar toggle and open a folder
5. Browse a remote folder: Click the globe button in the sidebar and paste an HTTP(S) directory URL

Remote folders

OpenMarkdownReader can turn common HTML directory indexes (including python3 -m http.server, Apache, and nginx auto-index pages) into a lazy, read-only sidebar tree. Sources that advertise HTTP PUT support can also save edits back to the remote machine with ⌘S. Remote saves use ETag or Last-Modified guards so a newer remote version is never silently overwritten.

The app also accepts a JSON manifest:

{
  "name": "Project Notes",
  "capabilities": { "write": true },
  "entries": [
    { "name": "README.md", "path": "README.md" },
    { "name": "Research", "type": "folder", "path": "research/" }
  ]
}

For a writable private share, run the bundled companion server on the machine that owns the files:

npm run serve:remote -- "/path/to/notes" --port 8847
tailscale serve --bg --https=8847 http://127.0.0.1:8847

The server binds to localhost by default; Tailscale supplies the private network access. Add --read-only if you only want browsing. Paste the resulting HTTPS folder URL into the globe-button dialog. Quick Open (⌘P) also offers both Open Remote File and Browse Remote Folder.

For remote files, ⌘S saves back only when write support is advertised. Read-only sources offer Save a Copy… instead. ⇧⌘S always saves a local copy while keeping the tab associated with its remote URL.

Supported File Types

• .md
• .markdown
• .mdown
• .mkd
• .txt

Notes & Future Plans

App Size (~200MB)

The app is large because Electron bundles a full Chromium browser. This is standard for Electron apps (VS Code, Slack, Discord are similar sizes). The universal binary (ARM + Intel) doubles the size.

Potential optimizations (no current intent to implement):

• Build single-architecture versions (~100MB each for ARM or Intel separately)
• Port to Tauri (~15-20MB) which uses the system webview instead of bundling Chromium
• Port to Neutralino (~3-5MB) for even smaller size

For now, the convenience of Electron's development experience outweighs the size concern.