Double-click a Markdown file on a Mac and it opens in whatever app grabbed the extension last — Xcode, maybe, or TextEdit, or some editor you installed in 2023 and forgot about. Press Space in Finder and macOS shows you the raw markup. There's still no built-in way to just read a Markdown file, which is a strange gap now that Markdown is everywhere: READMEs, docs, changelogs, and everything your AI assistant writes.
Here are the seven apps worth considering. I make one of them — Peekdown — so keep that in mind. I checked every price, version, and release date below on July 9, 2026 against each app's own site or repo.
Peekdown — $3.99
Mine. It's a native SwiftUI viewer with a Quick Look extension, so it covers both the Space bar and the double-click: press Space in Finder and .md and .mdx files render GitHub-style instantly; double-click and you get a reading window instead of an editor. Rendering matches GitHub exactly for pure Markdown (GitHub-side extras like @mentions are out of scope). It handles Obsidian syntax — all 13 callout types, wikilinks, highlights, tags — reloads files automatically when they change on disk, and lets you annotate rendered output and send the markup back to your AI. There's a side-by-side editor for quick fixes. It's a 13MB download, uses about 70MB of RAM, and needs macOS 15.0 or later.
From an App Store review, June 2026:
Peekdown is finally the app that I can confidently set as the default for all of my Markdown files on macOS… It's fast to run and open. Its user experience is 99% invisible. It just works.
$3.99 one-time, actively maintained, localized in English, Spanish, German, and Japanese.
Marked 2 — $13.99
Brett Terpstra's previewer, on the App Store since 2014, and the deepest Markdown tool on the Mac: custom pre- and post-processors (arbitrary shell scripts), MultiMarkdown, CriticMarkup, Fountain, Scrivener previews, HTML/PDF/Word export, readability stats, link validation. If your Markdown gets processed and exported into other formats, this is the one to buy.
It's a previewer you pair with an editor, though, not a default opener — you write in your editor and Marked re-renders on every save. There's no Quick Look and no Finder integration. The last update was v2.6.46 in March 2025, and new development has moved to Marked 3 (macOS 11+, $2.99 a month or $69.99 one-time at launch pricing). Marked 2 runs on macOS 10.12 or later — the widest compatibility here by years.
MacDown — Free
The classic free, open-source (MIT) split-pane editor — source on the left, preview on the right. For years it was the default free answer on the Mac.
The last release was v0.7.3 in January 2020, though, before Apple Silicon Macs existed, and nobody has shipped one since. It still runs under Rosetta 2 as of mid-2026, but macOS has started warning users that it "will eventually stop working," and Apple has said Rosetta 2 only sticks around through macOS 27. It's hard to recommend as a default app at this point. If free is the requirement, MDHero and QLMarkdown further down are free and maintained.
Typora — $14.99
The WYSIWYG option: you type Markdown syntax and it turns into formatted text as you go — no split pane, no separate preview. If you spend your day writing Markdown rather than reading it, Typora is the nicest place to type on this list. In-place table editing, math via MathJax, Mermaid diagrams, and export to PDF, docx, LaTeX, and EPUB.
As a default opener it's the wrong shape: it's a full writing environment (built on Electron), it renders in its own look rather than GitHub's, and there's no Quick Look. $14.99 for up to 3 devices with a 15-day free trial; macOS, Windows, and Linux; actively maintained.
MDHero — Free
Free, basic, no-strings viewing. MIT-licensed, built with Tauri and Rust — under 8MB, fully offline, no accounts or telemetry — with some genuinely current features: an LLM paste mode that cleans up ChatGPT and Claude output, KaTeX math, Mermaid diagrams, syntax highlighting for 25+ languages, and Vim keybindings if that's your thing.
It's young — v0.2.7 shipped July 2026 — so expect some rough edges. The Mac build is Apple Silicon only (macOS 12+), there's no Quick Look, and the UI is a webview rather than native. The developer says it'll stay free — no tiers, no upsell. As a $0 reader on a recent Mac, it's a solid choice.
MacMD Viewer — $19.99
The one other app here aiming at the same job as Peekdown: a dedicated viewer, not an editor. Their pitch is "Preview.app for PDFs, but for Markdown," and it's a good pitch. Native SwiftUI, Quick Look integration, live reload at around 50ms, a table-of-contents sidebar, and seven themes including GitHub, Dracula, and Nord. Its standout feature is Mermaid diagrams without plugins.
Two things to weigh: it's viewer-only, so fixing a stray typo means switching apps, and at $19.99 it's the most expensive app here, sold from their own site with a 14-day money-back guarantee. I also couldn't find a minimum macOS version published anywhere on the site, so check before you buy. If you need Mermaid in a viewer, it's a legitimate pick.
QLMarkdown — Free
sbarex's free, open-source (GPL-3.0) Quick Look extension. Press Space in Finder and it renders the file through cmark-gfm — GitHub's own fork of the reference parser — with extensions for emoji, MathJax math, Mermaid diagrams, and sub- and superscript. It handles .md, .mdx, .rmd, .qmd, and textbundle files, and it's actively maintained: 1.5.2 shipped June 30, 2026.
That's all it does — there's no app window, no editing, nothing beyond the Quick Look panel. Setup takes a few steps: install from Homebrew or GitHub, launch the app once so macOS discovers the extension, then enable it in System Settings. But if free Space-bar previews are all you want, this is the answer.
Side by side
| App | Price | Last release | Native or Electron | Quick Look | Obsidian syntax | GFM fidelity |
|---|---|---|---|---|---|---|
| Peekdown | $3.99 | Active (2026) | Native (SwiftUI) | Yes | Yes | GitHub-exact |
| Marked 2 | $13.99 | Mar 2025 (v2.6.46) | Native | No | No | GFM processor included |
| MacDown | Free | Jan 2020 (v0.7.3) | Native (Cocoa) | No | No | Frozen in 2020 |
| Typora | $14.99 | Active | Electron | No | No | GFM syntax, own styling |
| MDHero | Free | Jul 2026 (v0.2.7) | Tauri (Rust) | No | No | Not documented |
| MacMD Viewer | $19.99 | Active | Native (SwiftUI) | Yes | No | GitHub theme |
| QLMarkdown | Free | Jun 2026 (v1.5.2) | Native | Yes | No | cmark-gfm (GitHub's parser) |
"Obsidian syntax" here means callouts, wikilinks, and highlights. "No" means I couldn't find it in the app's own documentation.
Which one should you get?
- Your Markdown gets processed or exported to PDF/Word: Marked 2, or Marked 3 — that's where the new development is going.
- You write in Markdown all day: Typora.
- You want free Space-bar previews: QLMarkdown.
- You want a free basic reader and you're on Apple Silicon: MDHero.
- You want Mermaid in a viewer and $19.99 is fine: MacMD Viewer.
- Your Mac can't run anything newer: MacDown still works, for now.
- You want a default app for your Markdown files — the thing that answers the double-click and the Space bar: Peekdown. That's what I built it for.