MDView

MDView is a fast, private, read-only Markdown viewer for macOS 26 and later. It opens local Markdown documents as a native document app, renders entirely on-device, includes Finder Quick Look previews, and never collects document or usage data.

It includes CommonMark and GFM reading, tables and tasks, footnotes, front matter, callouts, wikilinks, Mermaid, KaTeX, highlighted code, a live outline, private folder search, multi-file tabs, Apple-style Find with result counts, live reload, themes, safe custom CSS, PDF/HTML export, printing, App Shortcuts, and optional document-grounded Apple Intelligence tools.

MDView remembers the reading environment between launches: theme, text size, reading width, custom CSS, recent files, trusted folders/hosts, selected sidebar mode, collapsed panels, and window sizes.

Highlights

• Native DocumentGroup viewer for local Markdown files, recent documents, multiple windows, tabs, Share, Print, and state restoration.
• Folder sidebar with duplicate-file disambiguation, recent files, contextual actions, and editor handoff.
• Read-only privacy model: documents stay on the Mac; remote resources remain blocked until explicitly trusted.
• Finder Quick Look extension and App Intents for rendering Markdown to PDF or HTML.
• Optional on-device Apple Intelligence actions for summaries, actions, and document questions when the system model is available.

Build

xcodegen generate
xcodebuild -project MDView.xcodeproj -scheme MDView -destination 'platform=macOS' build
xcodebuild -project MDView.xcodeproj -scheme MDView -destination 'platform=macOS' test

Open MDView.xcodeproj to select your Apple Development team before archiving for distribution.

The current local development build can be installed at /Applications/MDView.app by copying DerivedData/Build/Products/Debug/MDView.app after a successful build. Use Finder's Open With > MDView, then Change All, to make it the default for Markdown files.

Verification

The standard local verification pass is:

xcodebuild -project MDView.xcodeproj -scheme MDView -configuration Debug -derivedDataPath DerivedData CODE_SIGNING_ALLOWED=NO build
xcodebuild -project MDView.xcodeproj -scheme MDView -configuration Debug -derivedDataPath DerivedData CODE_SIGNING_ALLOWED=NO test

Privacy

Documents stay on the Mac. Remote resources are blocked until the user explicitly trusts a host. MDView contains no analytics, advertising, account system, cloud service, or third-party AI provider.