I’ve been working on something small but useful, and it’s out now: Marked QL, a Quick Look extension that renders Markdown previews right in Finder. Select a .md file, hit Spacebar, and you get a real preview — not plain text, not a sad monospace dump, but actual formatted output with math, diagrams, syntax highlighting, the works.

It’s a companion to Marked, but it doesn’t require Marked. If you do use Marked 3, you’ll get shared preview preferences and an Open in Marked button when you want the full app. If you don’t, Marked QL still does its job on its own.

What it actually does

Marked QL registers as the Quick Look generator for Markdown files. That means anywhere Quick Look works — Finder, mostly — you get a rendered preview powered by Apex, the unified Markdown processor I’ve been building that combines CommonMark, GFM, MultiMarkdown, Kramdown, and a bunch of other syntax into one engine.

So yeah, your README with Mermaid diagrams, your notes with $inline math$, your code samples with highlighting… they all show up properly. Tables, footnotes, task lists, callouts — the kind of stuff you’d expect from a serious preview tool, not a bare Quick Look text view.

You can also tweak things in the Marked QL settings: Apex processing mode, preview style, syntax theme, MathJax and Mermaid toggles, that kind of thing.

Why Apex matters here

Marked QL is the first shipping app that puts Apex in your daily workflow. That’s exciting to me because it’s the first step toward incorporating Apex into Marked 3 — same rendering engine, same syntax flexibility, eventually in the app you already use for live preview and export.

For now, Apex lives inside Marked QL’s Quick Look previews. If you want to dig into what Apex supports, apexmarkdown.org has the full story.

Finder, Terminal, whatever

The obvious use case is Finder: browse to a file, Spacebar, done. But if you live in Terminal, you can hook into macOS’s built-in qlmanage command and preview from the shell too. I use Fish, so my function looks like this:

function ql --description 'Quick Look a specified file or directory'
  if [ (count $argv) -gt 0 ]
    qlmanage >/dev/null 2>/dev/null -p $argv &
  else
    echo "No arguments given"
  end
end

Then ql README.md in a project directory opens a Quick Look preview — and if Marked QL is handling Markdown, you get the nice rendered version.

Bash and Zsh folks can use the same idea:

ql() {
  if [ $# -gt 0 ]; then
    qlmanage >/dev/null 2>/dev/null -p "$@" &
  else
    echo "No arguments given"
  fi
}

Drop it in your shell config, source it, and you’re set.

One-time purchase, no subscription

Marked QL is $4.99, one time, on the Mac App Store. No subscription, no account nonsense. Requires macOS 13.0 or later.

If you’re already a Marked user, think of it as the instant-preview sidekick — Spacebar in Finder when you just want to see a file, Marked when you need live preview, proofreading, export, and the rest. If you’re not a Marked user, it’s still a great little tool on its own.

Learn more about Markdown QL Get it on the Mac App Store

Go check it out

I’ve put together a proper landing page with screenshots, FAQ, and the Terminal setup details at markedapp.com/ql. That’s the best place for the full feature list, App Store link, and all the nerdy details.

If you’ve been wishing Quick Look didn’t treat Markdown like a text file, this is what you’ve been waiting for. Take it for a spin and let me know what you think.