A tool to generate Markdown file QuickLook previews for macOS Catalina and up

Latest Release: 1.2.0


How to Use PreviewMarkdown

Install the app and run it. This will register the availability of the app’s QuickLook extensions, Previewer and Thumbnailer. You can now quit the app: just click OK:

The PreviewMarkdown app UI

Using QuickLook in Finder — select a Markdown file (.md, .mdown or .markdown, for example) and press space — will pop up a rendered image of file:

The PreviewMarkdown app UI

You can disable or re-enable Previewer and Thumbnailer in System Preferences > Extensions:

Control PreviewMarkdown extensions in System Preferences, Extensions

For some background information on how Catalina delivers QuickLook previews, please see this blog post.

Customise the Preview

Version 1.2.0 adds a Preferences panel, which allows you to adjust some of the key elements of the preview:

  • The colour of code blocks.
  • Code blocks’ monospaced font.
  • The base body text size.
  • The body text font.
  • Whether preview should be display white-on-black even in Dark Mode.

The PreviewMarkdown app preferences

Changing these settings will affect previews immediately, but may not affect thumbnail until you open a folder that has not been previously opened in the current login session.

Feedback and Bug Reports

You can use the in-app UI to submit feedback or contact me. Just click in the Send Feedback button in the main window, or select Report a Bug… from the Help menu:

The PreviewMarkdown app feedback mechanism

Please include your email address if you would like a response. I can’t respond without one. Please see the privacy policy for details of email address usage.


If it appears that either Previewer or Thumbnailer are not working after you have run the host app, please log out of your Mac and then log back in. A future release will offer to do this for you.

Some applications which can edit Markdown files may register a non-standard, proprietary Uniform Type Identifier (UTI) for Markdown files. PreviewMarkdown may not be aware of these UTIs and therefore may not be able to preview and thumbnail these files on your system. If you encounter this issue — typically, previews of markdown files will show the raw formatting text — please run utitool to see your system’s registered Markdown file UTI. This UTI will automatically be included in any message you send using PreviewMarkdown’s feedback facility.

Enjoyed Using PreviewMarkdown?

If you have found PreviewMarkdown to be useful, please consider writing a positive review on the Mac App Store, or simply give it a rating.

Thank you!


In addition to its own code, PreviewMarkdown makes use of code from the following sources:

Release Notes

  • 1.2.0 4 February 2021
    • Add preview display preferences (requested by various anonymous feedback senders)
    • Add file type ident tag to thumbnails (requested by @chamiu).
    • Add What’s New sheet to be shown with new major/minor versions.
    • Include local markdown UTI with user-submitted feedback.
    • Add link for app reviews.
  • 1.1.4 16 January 2021
    • Add UTI net.ia.markdown.
  • 1.1.3 13 January 2021
    • Add UTI writer.pro.markdown.
  • 1.1.2 18 November 2020
    • Apple Silicon support.
  • 1.1.1 1 October 2020
    • Add report bugs/send feedback mechanism.
    • Add further usage advice to the main window.
    • Handle markdown formatting not yet rendered by SwiftyMarkdown: three-tick code blocks; HTML symbols; space-inset lists.
  • 1.1.0 25 September 2020
    • Add macOS Big Sur support.
    • Better macOS dark/light mode support.
    • Migrate engine to SwiftyMarkdown 1.2.3.
  • 1.0.5 9 April 2020
    • Mac App Store version.
  • 1.0.4 Not Released
  • 1.0.3 10 December 2019
    • Add the version number to the app info dialog.
  • 1.0.2 4 December 2019
    • Fix random crash (string index out of range in SwiftyMarkdown).
  • 1.0.1 20 November 2019
    • Correct thumbnail styling.
  • 1.0.0 8 November 2019
    • Initial public release.

Source Code

You can view PreviewMarkdown’s source code at GitHub.

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Site Last Updated: 7 April 2021