Markdown Viewer

A native macOS Markdown viewer built with SwiftUI and WebKit.

Features

• Native macOS app built with SwiftUI and WebKit.
• Tabbed windows with keyboard shortcuts.
• Auto-reload on file change with dismissable notification.
• Mermaid diagram rendering.
• Table of contents sidebar (pinnable or hover to reveal).
• Syntax highlighting for fenced code blocks.
• Front matter preview.
• Find-in-page with next/previous navigation.
• Zoom controls (in/out/actual size).
• Open Recent menu for quick access to files.
• Configurable external editor with customizable keyboard shortcut.
• Optional bring-to-front when a file is modified externally.

External Editor

Open the current file in your preferred editor directly from the viewer. Configure the editor and keyboard shortcut in Settings (Cmd+,).

• Default shortcut: Cmd+E
• Supported editors: Any application that accepts file URLs (Sublime Text, VS Code, BBEdit, etc.)
• Setup: Settings > External Editor > Choose, then select an app from /Applications
• Custom shortcut: Settings > Keyboard Shortcut — click the recorder and press your desired key combination

If no editor is configured, the first use will prompt you to select one.

Bring to Front on File Change

When enabled, the viewer window automatically comes to front whenever the monitored file is modified externally. Useful when editing in a separate application and wanting the preview to surface after each save.

• Toggle: View > Bring to Front on File Change
• Default: Off

Build & Run

# Run from source (development)
swift run MarkdownViewer

# Build release .app bundle
./build.sh

The release build creates Markdown Viewer.app in the repo root.

Requirements

• macOS 14+
• Xcode Command Line Tools