The markdown viewer and editor
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). Apple-notarized DMG — no Gatekeeper workarounds needed. Intel Mac support coming.Why Mac users choose MDHero as their markdown viewer for Mac
Apple-notarized — installs like a real Mac app
Signed with an Apple Developer ID and notarized by Apple. First launch shows only the standard "downloaded from the Internet" prompt — 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.
Edit in place with ⌘E
Press ⌘E on any local file to flip into a focused editor. ⌘S saves to disk. Scroll position follows you between viewer and editor — line by line.
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.
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 |
Drag, double-click, done. Apple-notarized — no workarounds.
As of v0.2.4 MDHero is signed with an Apple Developer ID and notarized by Apple. First launch shows the standard macOS "downloaded from the Internet" prompt — click Open, and it launches normally from then on. No System Settings detour, no Terminal commands.
Steps
- Download
MDHero_0.2.6_aarch64.dmgand open it - Drag MDHero to your Applications folder
- Double-click MDHero — macOS asks "Are you sure you want to open it?" because it was downloaded from the Internet
- Click Open. From now on, double-clicking just works.
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 by Apple — Apple has scanned the binary and confirmed it contains no known malware.
- 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 a real one. TextEdit opens .md files as raw text, and 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 notarized by Apple as of v0.2.4, which means Apple scanned the build for malware — it opens without any Gatekeeper workaround.
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.
Also available for Windows.