The free markdown viewer
your Mac deserves.
A free, open source markdown viewer for Mac and a lightweight editor — fast, focused, and built for Apple Silicon.
Under 8MB. The free markdown viewer Mac users keep installing instead of TextEdit. Built native for Apple Silicon (M1–M4). Open any .md file with a double-click, then hit ⌘E to edit and ⌘S to save — no accounts, no uploads.
macOS 12+ on Apple Silicon (M1, M2, M3, M4). Notarized and stapled DMG — opens with no Gatekeeper warning. Intel Mac support coming.Why Mac users choose MDHero as their markdown viewer for Mac
Notarized — installs like a real Mac app
Signed with an Apple Developer ID, and as of v0.2.10 the DMG is notarized and stapled by Apple, so it opens with no Gatekeeper warning at all — no xattr, no System Settings detour. Native Apple Silicon build, under 8MB, launches in under a second.
Retina-sharp rendering
San Francisco-friendly typography, syntax colors for 25+ languages, KaTeX equations, and Mermaid flowcharts. Appearance follows your macOS dark mode setting automatically.
Paste from ChatGPT or Claude
LLM paste mode cleans up the escaped newlines and stray backslashes that break formatting when you copy AI output. Paste, render, read.
View, Split, or Edit
A real markdown editor for Mac, built into the viewer. Switch between View, Split, and Edit from one control — Split shows the editor and a live preview side by side. Line numbers, ⌘S to save, and an unsaved-changes warning before you close.
Present straight from a .md file
Add marp: true to the front matter and MDHero opens the file as a native slideshow — arrow keys, Space, and optional page numbers. No Marp CLI, no export, no browser.
Navigate like you're in Xcode
⌘T for new tabs, drag to reorder, ⌘F to search. Table of Contents sidebar, pinned project folders, and optional Vim keybindings for terminal-native developers.
Double-click any .md in Finder
Register MDHero as your default markdown handler. Open local files, GitHub URLs, Claude Code plans, or paste raw markdown — one app handles all of it.
Reloads the moment the file changes
Edit a .md in another editor, pull a branch, or regenerate docs and MDHero repaints it — including tabs sitting in the background. Unsaved edits are never lost: the tab flags the change and Save asks first. Your tabs also come back after a restart.
Print to paper or PDF
⌘P opens the standard macOS print dialog on the rendered view — so Save as PDF gives you a formatted PDF of your markdown without an export step or a browser round-trip.
No cloud, no telemetry
Everything stays on your Mac. No file uploads, no account creation, no data collection. Works fully offline — open a file in airplane mode and it just works.
How MDHero compares on macOS
There are many great markdown tools for Mac. Here's how MDHero fits in.
| MDHero | Marked 2 | MacMD Viewer | Typora | QuickMD | |
|---|---|---|---|---|---|
| Price | Free | $13.99 | $19.99 | $14.99 | Free |
| Open source | Yes | No | No | No | Yes |
| App size | ~8MB | ~30MB | ~15MB | ~90MB | ~10MB |
| Built-in editor | Yes | No | No | Yes | No |
| Mermaid diagrams | Yes | No | Yes | Yes | Yes |
| KaTeX math | Yes | Yes | Yes | Yes | Yes |
| LLM paste mode | Yes | No | No | No | No |
| Windows support | Yes | No | No | Yes | No |
Make Quick Look preview your .md files
The first thing every Mac user hits — and, as of v0.2.10, a one-install fix.
Select a .md file in Finder, press Space, and stock macOS shows you the raw source — hashes, asterisks and all. Quick Look ships no Markdown renderer, so it falls back to treating the file as plain text. Nothing is broken; the preview generator simply doesn't exist.
MDHero now supplies one. Installing MDHero adds a Quick Look extension, so Space renders the file in place — headings, tables, syntax-highlighted code, KaTeX math and Mermaid diagrams — without opening the app at all.
- Install MDHero and open it once, so macOS registers the extension.
- Select any
.mdfile in Finder and press Space. - Still raw text? Enable MDHero under System Settings → General → Login Items & Extensions → Quick Look.
For files you intend to actually read rather than glance at, make MDHero the default handler too: right-click any .md file → Get Info → expand Open with → choose MDHero → Change All. Space then previews it and double-click opens it in tabs, with find, editing and export.
Before v0.2.10 the usual workaround was QLMarkdown, a standalone plugin installed through Homebrew. It still works and remains a reasonable choice if you don't want MDHero — but it needs Terminal, it renders no syntax highlighting, math or diagrams, and macOS often needs convincing to trust it again after a system update. The full comparison is in Quick Look vs MDHero.
Markdown viewer, markdown reader, or markdown editor?
Three words for the same job — and the one case where the difference matters.
People look for the same thing under a lot of names: markdown viewer for Mac, markdown reader, md viewer, macOS markdown app. The request underneath is identical — render the file instead of showing me its syntax.
The distinction that matters is reading versus writing:
- A markdown viewer / reader renders a file so you can read it — a README, a spec, a plan, pasted AI output. Launch speed matters more than features.
- A markdown editor for Mac is for writing — hours at a time, where themes, export formats and typing feel earn their keep. Typora and iA Writer are editors.
MDHero is both, weighted toward reading. It opens as a viewer, and the View / Split / Edit switcher is there when you need it — Split puts the editor and a live preview side by side, with line numbers and ⌘S to save. Native Apple Silicon, ~8MB, MIT-licensed, so it's also a genuinely open-source markdown editor if that's what you were after.
If you draft long documents in Markdown daily, a dedicated editor is worth paying for. If you mostly read and edit occasionally, this is the smaller answer — see Typora vs MDHero for that comparison in full.
Drag, double-click, done. Notarized — no warning at all.
MDHero is signed with an Apple Developer ID, and as of v0.2.10 the DMG itself is notarized and stapled by Apple. It opens straight away — no Gatekeeper warning, no System Settings detour, no Terminal commands. Earlier releases showed a "downloaded from the Internet" prompt on first open; that step is gone.
Steps
- Download
MDHero_0.2.10_aarch64.dmgand open it - Drag MDHero to your Applications folder
- Double-click MDHero. It opens straight away — no Gatekeeper prompt to dismiss
- That first launch also registers the Quick Look extension, so Space on any
.mdfile in Finder shows it rendered
Requirements
- macOS 12 (Monterey) or later
- Apple Silicon (M1, M2, M3, M4) — Intel Mac support is on the roadmap
What's safe about this?
- The DMG is notarized and stapled by Apple — Apple has scanned the binary, confirmed it contains no known malware, and the ticket is attached to the image itself so the check works offline.
- MDHero is fully open source — every line of code is on GitHub.
- The build is automated on GitHub Actions from public source — no manual steps where something could slip in.
- Releases are downloadable directly from GitHub, not a third-party mirror.
Markdown on Mac — common questions
The questions people ask before picking a markdown viewer for Mac.
Is there a free markdown viewer for Mac?
Yes. MDHero is a free, open-source markdown viewer for macOS — a native Apple Silicon app around 8MB, MIT-licensed, with no paid tier and no account.
It renders GitHub-Flavored Markdown with syntax-highlighted code, KaTeX math, and Mermaid diagrams, and includes a lightweight editor (Cmd+E to edit, Cmd+S to save). See how it compares in our best free markdown viewers roundup.
How do I open a .md file on Mac?
macOS opens .md files in TextEdit by default, which shows raw markdown symbols instead of rendering them. Install a markdown viewer like MDHero, then set it as the default: right-click any .md file → Get Info → Open with → MDHero → Change All.
After that, double-clicking any markdown file shows it rendered. Full walkthrough: viewing markdown on Mac — the complete guide.
Does macOS have a built-in markdown viewer?
Not built in. TextEdit opens .md files as raw text, and stock Quick Look (spacebar in Finder) previews them as plain text without rendering headings, tables, or code blocks.
To read rendered markdown you need a third-party app such as MDHero (free, open source) or Marked 2 (paid). We compared the two approaches in Quick Look vs MDHero.
Is MDHero safe to install on a Mac?
Yes. MDHero is signed with an Apple Developer ID, and as of v0.2.10 the DMG is notarized and stapled by Apple — Apple scanned the build for malware, and the ticket travels with the file so the check works offline. It opens with no Gatekeeper warning at all.
The app is MIT open source and every release is built on public GitHub Actions CI, so the shipped binaries are auditable end to end.
Does MDHero run on Intel Macs?
MDHero currently requires an Apple Silicon Mac (M1, M2, M3, or M4) running macOS 12 or later. There is no Intel build yet — Intel support is planned.
If you need it sooner, open an issue on GitHub; demand is tracked there.
More on viewing markdown on Mac
Guides, comparisons, and quick tips from the MDHero blog.
How to view markdown files on Mac in 2026
Every way to open a .md file on macOS — Finder, Quick Look, Marked, Typora, MDHero — compared.
ComparisonQuick Look vs MDHero for markdown
When the built-in macOS Quick Look is enough, and when a dedicated markdown viewer for Mac wins.
RoundupBest free markdown viewers in 2026
The shortlist of free markdown apps for Mac, Windows, and beyond — with honest pros and cons.
Cross-platform user? See the Windows markdown viewer page, or browse all MDHero articles.
Free, open source, and built for your Mac.
Download MDHero and start viewing markdown files in seconds.