ReaddownMarkdown reader & Quick look preview for Mac

Setup

Get started in three clicks.

1. 1

   Install and open any .md file

   Drag Readdown to Applications. On first launch, it offers to become your default Markdown reader.

2. 2

   Enable Quick Look

   Readdown prompts you to enable Quick Look so you can preview .md files with spacebar in Finder. Click Open Extensions Settings to jump straight to Login Items & Extensions, then click ℹ︎ next to Quick Look.

   
3. 3

   Toggle Readdown on

   Switch Readdown on and click Done. Select any .md in Finder, press spacebar. Rendered.

   

Common Questions

• Why is Quick Look showing raw text instead of rendered markdown?

  The Quick Look extension needs to be enabled. Follow the setup steps above. If you just switched from another markdown previewer, relaunch Readdown. It resets the Quick Look cache on startup.

• Why did Quick Look stop working after I removed another markdown app?

  macOS needs to re-discover which extension handles markdown files. Quit and reopen Readdown. It automatically refreshes the Quick Look registry on launch. If that doesn't help, restart your Mac.

• Which file types can Readdown open?

  .md .markdown .mdown .mkd. All standard Markdown extensions. UTF-8, UTF-16, and Latin-1 encodings are detected automatically.

• How does syntax highlighting work?

  Code blocks with a language name on the opening fence (e.g. python, swift, json) are highlighted using that language. Blocks without a language are auto-detected from 19 common languages. For best results, always specify the language.

• Does Readdown support Mermaid diagrams?

  Yes. Use mermaid as the language on a fenced code block and it renders as a diagram. Flowcharts, sequence diagrams, pie charts, and more. Works fully offline.

• Can I edit files in Readdown?

  No. Readdown is read-only by design. It never modifies your files. Use your favorite editor to write, Readdown to read.

• How do I search within a document?

  Press ⌘F (or Edit → Find…) to open the find bar. ⌘G jumps to the next match, ⇧⌘G to the previous, Esc closes it. The match counter shows your position (“3 of 17”).

• How do I make Readdown my default markdown app?

  Readdown asks on first launch. You can also right-click any .md file in Finder → Get Info → Open With → select Readdown → Change All.

• "Set as Default" didn't work — what happened?

  Update macOS to 26.4+ or set Readdown as default manually: right-click any .md file in Finder → Get Info → Open With → Readdown → Change All.

• Does Readdown update automatically?

  Yes. Readdown checks for updates in the background via Sparkle. You can also check manually from Readdown → Check for Updates.

• How do I report a bug or request a feature?

  Open an issue on GitHub, or use Help → Send Feedback in the app.