peekdown

Quick Look extension for macOS

Press space.
Read Markdown.

Peekdown renders .md files right inside Finder’s Quick Look. Select a file, tap the space bar, and see headings, tables, code and task lists with clear native formatting. Free and open source.

brew install --cask h0ck3ystyx/tap/peekdown
Download installer · v1.1.1 Download ZIP
macOS 12+ Monterey or laterUniversal Apple silicon + IntelMIT licensed
peekdown-demo~/Projects
Favorites
Recents
Applications
Projects
Downloads
Locations
Macintosh HD
NameKindModified
CHANGELOG.mdMarkdownOct 21
README.mdMarkdownToday
hero-shot.heicHEIC imageOct 19
roadmap.mdMarkdownYesterday
design-sync.mdMarkdownOct 27
CONTRIBUTING.mdMarkdownSep 30
README.mdOpen with Xcode
spaceto preview

What renders

Readable Markdown, one keystroke away.

Peekdown renders common Markdown and selected GitHub-style features with a Swift renderer and native AppKit text.

Release status: Downloads below are v1.1.1. Mermaid diagrams and display math are experimental and off by default; enable them in Peekdown. Static MDX keeps components and expressions as source.

Markdown essentials

Headings, tables, task lists, strikethrough, links and blockquotes. Read your README without opening an editor.

Syntax-highlighted code

Fenced Swift, shell, JSON, YAML, Python, JavaScript, and TypeScript receive native syntax colors in padded code panels. Unknown languages stay readable as plain monospaced text.

Finder thumbnails

See a document’s first heading and a short text snippet in a styled Markdown thumbnail, alongside the full Quick Look preview.

Matches your Mac

Follows Light and Dark appearance using native system text colors, with system fonts for prose and monospaced fonts for code.

Private by design

Quick Look extensions run in Apple’s App Sandbox without network access. Remote images are not downloaded. The host app checks GitHub for updates only when requested. Downloads and installation remain manual.

Front matter aware

YAML front matter at the start of a document is hidden so the preview begins with your Markdown content.

YAML previews

Available in v1.1.1: press Space on .yaml or .yml for native syntax colors. Malformed or oversized files stay plain text; large files show a bounded prefix.

Preview appearance

Available in v1.1.1: choose text size, compact paragraphs, and code spacing in Peekdown. Close and reopen Quick Look to apply changes.

Native Mermaid · experimental

Experimental, off by default: small flowcharts and sequence diagrams render offline. Unsupported diagram families and directives remain source text.

Display math · experimental

Experimental, off by default: equations between standalone $$ or \[ / \] delimiter lines render natively. Inline math is not supported.

Static MDX previews

Available in v1.1.1: ordinary Markdown in .mdx files renders; imports, JSX, and expressions stay readable as source. Components and JavaScript never execute.

Check for updates

Choose Check for Updates… in Peekdown’s menu or window. See stable release notes and open GitHub to download. Checks run only on request; installation is manual.

Install

Choose how to install.

  1. Install the app

    Homebrew (recommended): Run this command. The Quick Look extensions register automatically on install.

    brew install --cask h0ck3ystyx/tap/peekdown

    Manual install: Download the signed, notarized installer. Choose Install for me only for ~/Applications without admin access, or Install for all users for /Applications with admin authorization. If needed, click Change Install Location…. Prefer a ZIP? Extract the ZIP and move the app to ~/Applications. Create that folder if needed.

  2. Open it once

    If you used the installer or ZIP, open Peekdown from the Applications folder so macOS can discover its extensions. You can quit it afterward. Homebrew installs handle this automatically.

  3. Turn on the extension

    If previews do not appear, look for Quick Look in System Settings. On recent macOS versions, go to

    General › Login Items & Extensions › Quick Look

    and switch on Peekdown.

  4. Press space on a Markdown file

    Select a Markdown file for a formatted preview. Version 1.1.0 also previews .yaml, .yml, and static .mdx files.

Homebrew commands

Update to the latest release or remove Peekdown.

# upgrade to the latest version
brew upgrade --cask peekdown

# uninstall
brew uninstall --cask peekdown

Supported files

ExtensionType identifier
.md .markdownnet.daringfireball.markdown
.mdown .mkd .mkdnnet.daringfireball.markdown
.yaml .yml (v1.1.1)public.yaml
.mdx (v1.1.1, static)com.markdownpreview.mdx

Preview not showing?

Reset the Quick Look cache, then select a Markdown file in Finder and press Space. Avoid keeping both Peekdown and the old MarkdownPreview app installed.

# clear cached generators and thumbnails
qlmanage -r && qlmanage -r cache

Playground

Try a Markdown demo.

Edit the Markdown on the left for an interactive browser demo. This demo uses a web renderer; Peekdown itself uses native AppKit text, so formatting and supported features differ.

notes.mdraw
Quick Lookrendered

Brand kit

An eye for Markdown.

The mark joins the Quick Look eye with Markdown’s down arrow. It draws on, settles, and blinks now and then. This landing-page artwork illustrates the Peekdown identity; Peekdown includes a native macOS icon based on this mark.

App icon mark
Mark · light
Mark · cobalt
Mark · highlighter
Cobalt#2D5BFF · links, actions
Ink#0F1726 · text, icon ground
Highlighter#FFD84D · page accents
Paper#F2F4F8 · backgrounds
Display
Aa ##
Bricolage Grotesque 800
Body
Aa ¶
IBM Plex Sans 400 / 600
Code
`a`
JetBrains Mono 400

Open source · MIT

Built in the open, in Swift.

Peekdown is a small Swift app with a QLPreviewingController extension and a bundled renderer. Bug reports, feature suggestions and parser fixes are all welcome.

Read the sourceReport an issueBuild instructions
git clone https://github.com/h0ck3ystyx/peekdown
cd peekdown
./scripts/test.sh
./build.sh
# Ad-hoc local build. See README
# for development signing.