Preview Markdown in Finder with Quick Look.

Select a Markdown file in Finder and press Space. With MarsDawn installed, Quick Look shows the rendered page instead of plain text.

What the preview shows

The rendered page, drawn by the same renderer as MarsDawn's preview pane.
Mermaid diagrams, KaTeX math and highlighted code blocks.
The preview theme you picked in MarsDawn, in light or dark.
Web images stay blocked, and pictures stored next to the file can appear as placeholders.

How to preview a Markdown file with Quick Look

Install MarsDawn. Download MarsDawn from the Mac App Store. The Quick Look extension is part of the app.
Select a Markdown file. In Finder, click a .md file once.
Press Space. The rendered preview opens. Press Space again to close it.
If you see plain text, switch the extension on. Open System Settings, go to General ▸ Login Items & Extensions, click the Info button next to Quick Look under Extensions, turn on MarsDawn Preview, then click Done.

Not locked by the trial

Quick Look keeps working after the trial ends. It shows the same rendered preview while the trial runs, after it ends and after you unlock. After the trial ends and until you unlock, MarsDawn's own windows open with their content covered; Finder previews are unchanged. The trial and unlock page sets all three stages side by side.

Questions and answers

How do I preview a Markdown file in Finder?

Select the file and press Space. With MarsDawn installed, Quick Look shows the rendered page, with Mermaid diagrams, KaTeX math and highlighted code.

Does Quick Look still work after the 14-day trial?

Yes. Quick Look is not locked by the trial. It keeps rendering Markdown files while the trial runs, after it ends and once you unlock.

Why does Quick Look show plain text?

The Quick Look extension may be switched off. Open System Settings, go to General ▸ Login Items & Extensions, click the Info button next to Quick Look under Extensions, turn on MarsDawn Preview, then click Done.

Does Quick Look cost extra?

No. The Quick Look extension is part of MarsDawn, with no separate purchase. MarsDawn is a free download with a 14-day trial and a one-time USD 4.99 unlock, and Quick Look works with or without the trial.

Which version of macOS does it need?

MarsDawn needs macOS 26 or later.