Checkout plan
Architecture
Tasks
- Payment steps
- Coupon tests
Read every .md the way it was meant to look.
From a quick Space-bar peek in Finder to a whole project open in tabs: everything MDLumen does for the Markdown your AI tools write.
01
IN FINDER
Press Space. Read it formatted.
Quick Look shows any .md file with headings, tables, code and diagrams, right in Finder and Spotlight, without opening an app.
Your AI tool saved a .md file. Click it in Finder.
02
IN THE APP
Your whole project, one window.
Tabs, a folder sidebar, search across every file, live reload while your agent writes, and export when you need to share.
A plain .md file becomes a clean, readable document.
EVERYTHING INCLUDED
Everything for the reading side.
Quick Look
Press Space on any .md in Finder, Spotlight or an Open dialog and read it formatted.
SpaceMermaid diagrams
Flowcharts, sequence, state, class, Gantt, pie and more, drawn right in the page. No setup.
New
Tabs
Keep the plan, the spec and the README open side by side and switch in one click.
⌃TabNew
Folder view
Open a whole project. Every Markdown file shows up in the sidebar, sorted and searchable.
⇧⌘ONew
Search every file
Find text across the whole folder, with match counts per file, and jump straight to it.
⇧⌘FLive reload
Leave it open while Claude Code or Cursor writes. Each save shows up instantly, scroll position kept.
New
Export to PDF, Word & HTML
One-click export in your current theme. Word files keep real headings, lists and tables.
⇧⌘DSyntax highlighting
Readable code blocks for the languages you use, with one-click copy.
Themes, dark mode & zoom
Daylight, Midnight and Sepia, or follow macOS. Zoom text and diagrams from 50% to 300%.
⌃⌘TOutline & reading time
A table of contents that follows your scroll, with word count and reading time.
Back to the source
Open the file in your editor or copy the raw Markdown in one shortcut.
⌥⌘CKEYBOARD FIRST
Shortcuts
Everything is a keystroke away.
OpenQuick Look preview in FinderSpace
OpenOpen a file⌘O
OpenOpen a folder⇧⌘O
TabsClose tab⌘W
TabsNext tab⌃Tab
TabsJump to tab⌘1–9
FindFind in this file⌘F
FindSearch all files in the folder⇧⌘F
ExportExport as PDF⇧⌘P
ExportExport as Word (.docx)⇧⌘D
ExportExport as HTML⇧⌘H
ExportPrint⌘P
ViewZoom in⌘+
ViewZoom out⌘−
ViewActual size⌘0
ViewNext theme⌃⌘T
SourceOpen in your editor⇧⌘E
SourceCopy the Markdown source⌥⌘C
WHY NOT ELECTRON
Built in Rust on macOS's own WebKit. No Electron.
Electron apps ship a whole copy of Chrome. MDLumen uses the WebKit already on your Mac and a Rust engine for parsing and search, so it stays small, fast and light on memory.
| Feature | MDLumen | Typical Electron viewers |
|---|---|---|
| Small download, fast to open (Rust engine, no bundled browser) | ||
| Quick Look preview in Finder | ||
| Mermaid diagrams without plugins | Varies | |
| Reads a whole folder with search | Varies | |
| Works fully offline | Varies | |
| No subscription | Varies |
FAQ
Feature questions
How do I preview Markdown in Finder?
Install MDLumen and turn on its Quick Look extension once (MDLumen shows you how). Then select any .md file in Finder and press Space.
Which Mermaid diagrams are supported?
The main Mermaid types, including flowcharts, sequence, class, state, entity-relationship, Gantt, pie, mindmap and timeline diagrams.
Can I export to Word?
Yes. MDLumen exports Word (.docx) files with real heading styles, lists, tables, links and code, plus PDF and HTML.
Does it keep up while my AI agent writes?
Yes. Live reload watches the open files and updates the page on every save, without jumping back to the top.
Can I edit files?
MDLumen 1.0 is a reader, so your files are never changed. Use ⇧⌘E to open the file in your editor.
Does it follow dark mode?
Yes. Pick Daylight, Midnight or Sepia, or let MDLumen follow your macOS appearance.
Is every feature included in the price?
Yes. One licence at $6.99 (regular $13.99) unlocks every feature for you on up to 3 Macs, with all 1.x updates.
Try the free browser tools
Every feature. One price.
Free for 2 days. Then $6.99 once (regular $13.99), with a 14-day refund.
Try MDLumen free