MacMD Viewer vs MDHero: Free and Open Source, or Finder Preview (2026)
MDHero is free, MIT-licensed, under 8 MB and renders KaTeX — but it is Apple Silicon only and ships no Quick Look extension. Where each app wins, checked at the source.
MacMD Viewer is a native SwiftUI Markdown viewer — open any .md file and it renders instantly with Mermaid diagrams, syntax highlighting, and a QuickLook extension for Finder. No Chromium, no subscription, no account. $19.99 one-time.
Learn more about MDHero on their official site, or see all MacMD Viewer features.
- Running on 250+ Macs
- Reviewed on Trustpilot
- On Homebrew & Setapp
MDHero is free, open source and actively developed, and it does things I do not: math, editing, Marp slideshows, Windows and Linux builds. Install it first. MacMD Viewer is the answer to two questions MDHero does not answer today — will it run on my Intel Mac, and can I read the file straight from Finder with the spacebar.
How Does MacMD Viewer Compare to MDHero?
| Feature | MacMD Viewer | MDHero |
|---|---|---|
| Price | $19.99 one-time | Free, MIT licence |
| Intel Mac support | Yes — universal binary | No — Apple Silicon only, Intel listed as coming |
| Quick Look preview in Finder | Yes | No — its own guide explains the workaround instead |
| Minimum macOS | 14.0 | 12.0 |
| Read-only | Yes, by design — it cannot alter your file | No — View, Split and Edit modes, ⌘S saves |
| LaTeX / math | No | Yes (KaTeX) |
| Mermaid diagrams | Yes — bundled, offline, also inside Quick Look | Yes |
| Document themes | 12 built-in | Follows the system light and dark appearance |
| Syntax highlighting languages | ~34 | 25+, per its own site |
| Version | 1.6.x | 0.2.8 — pre-1.0 |
| App size | 5.4 MB DMG, 16 MB installed | Under 8 MB |
| Platforms | macOS only | macOS, Windows, Linux |
| Slideshows | No | Yes — `marp: true` in the front matter opens the file as a deck |
| Support | One paid developer answering email | GitHub issues, MIT licence, no warranty |
$19.99 one-time · 14-day money-back · No subscription
What Does Each Tool Cost Over Time?
| Period | MacMD Viewer | MDHero |
|---|---|---|
| Purchase price | $19.99 | Free (MIT licence) |
| After 1 year | $19.99 | Free (MIT licence) |
| After 3 years | $19.99 | Free (MIT licence) |
Both MacMD Viewer and MDHero are one-time purchases. No recurring costs.
What Are the Pros and Cons?
MacMD Viewer
Pros
- +Runs on Intel Macs; MDHero is Apple Silicon only today
- +Quick Look extension — press Space in Finder and the document renders
- +12 selectable document themes rather than system light and dark
- +Mermaid ships inside the app and the Quick Look extension, so diagrams render with no network
- +Read-only by design, which means the app you use to read cannot save over the file
- +Paid support from a named developer, plus Setapp and Homebrew distribution
Cons
- -Costs $19.99 where MDHero costs nothing and is MIT-licensed
- -No math rendering; MDHero renders KaTeX
- -Requires macOS 14; MDHero runs on macOS 12
- -No editing at all — if you want to fix a typo you saw, you leave the app
- -No Marp slideshow mode, no Vim keybindings, no LLM paste cleanup
- -macOS only; MDHero also ships Windows and Linux builds
- -~34 syntax highlighting languages, and MDHero's source is auditable while mine is not
MDHero
Pros
- +Free and open source under the MIT licence, 96 stars, last push 2026-08-10 (GitHub API, 2026-08-11)
- +Under 8 MB, native Apple Silicon build, Apple-notarized DMG
- +KaTeX equations and Mermaid diagrams
- +A real editor built into the viewer — View, Split and Edit, with ⌘S and an unsaved-changes warning
- +LLM paste mode that strips the escaped newlines and stray backslashes AI output arrives with
- +Marp slideshows straight from a `.md` file, with no CLI and no browser
- +Runs on macOS 12, and also ships for Windows and Linux
- +Optional Vim keybindings and pinned project folders
Cons
- -Apple Silicon only — Intel support is announced as coming, not shipped
- -No Quick Look extension; its own guide tells you to use Open With instead, so Space in Finder still shows raw text
- -Version 0.2.8 — pre-1.0 software, with the stability expectations that implies
- -Appearance follows the system light and dark setting; there is no theme picker
- -No support contract; the MIT licence ships the software as is
- -Being an editor as well as a viewer means it can write to the file you opened to read
When Should You Choose MDHero vs MacMD Viewer?
Choose MDHero if:
- →You need to write and edit Markdown files, not just read them
- →You work across Mac, Windows, and Linux
- →You prefer a WYSIWYG or split-pane editing experience
Choose MacMD Viewer if:
- →You primarily read and review Markdown files, not write them
- →You want QuickLook preview: press Space in Finder to see any .md file rendered
- →You need Mermaid diagram rendering without plugins or configuration
- →You want a native macOS app that launches instantly and uses minimal resources
$19.99 one-time · 14-day money-back · No subscription
MacMD Viewer vs MDHero: which one should you install?
MDHero is free, MIT-licensed, under 8 MB, renders KaTeX and Mermaid, edits as well as reads, opens Marp slideshows straight from a .md file, and ships for Windows and Linux too. It is developed in the open at github.com/vaibhav-kakde-in/mdhero — 96 stars, 2 open issues, last push 2026-08-10 (GitHub API, checked 2026-08-11).
Install it. It costs nothing and it is good. I am Arthur, the solo developer of MacMD Viewer, which costs $19.99, and this page is about the two specific cases where paying makes sense anyway.
Who MacMD Viewer is built for
MDHero is built by a developer for developers — Vim keybindings, split editing, ⌘S, Marp decks, an MIT repository you can read. That is a coherent audience and it is not entirely mine.
About half the people who buy MacMD Viewer are not developers at all. One wrote: "I am not a developer and don't have other software on my computer besides TextEdit to work with MD files. Diving into the AI vibe coding world though…" Another: "AI loves producing markdown files during software development, and MacMD makes them easier to review."
So the segment is someone whose Mac filled up with .md files they did not write, produced by Claude, ChatGPT, Cursor or Copilot, who wants to read them from Finder without learning a tool — and who will never press ⌘E to edit one. If that description makes you think "I would absolutely edit it", MDHero is the better fit and it is free.
Case one: your Mac has an Intel processor
MDHero's download page is explicit — macOS 12 or later, on Apple Silicon, M1 through M4, with Intel support listed as coming (mdhero.app, checked 2026-08-11).
If your Mac is a 2019 MacBook Pro or a 2018 mini, that is the end of the comparison. MacMD Viewer ships a universal binary and runs on both architectures; MDHero, today, does not run on yours at all.
Note the trade in the other direction: MDHero supports macOS 12, and MacMD Viewer requires macOS 14. So on an Apple Silicon Mac stuck on Monterey or Ventura, the situation reverses exactly and MDHero is the one that installs.
Case two: you read Markdown from Finder
MDHero publishes a guide about why Quick Look will not preview your .md file. It is accurate: macOS has no built-in Markdown renderer, so Space shows you hashes and asterisks. Its recommended fix is to right-click the file and use Open With — that is, to open the app.
MacMD Viewer takes the other route and ships a Quick Look extension, so Space in Finder renders the document where it sits, Mermaid diagrams included, without launching anything.
Both are legitimate designs. The one you want depends on a habit: if you flick through a folder of files your agent just wrote, using arrow keys and the spacebar, the extension is the entire product. If you open one document and stay in it, Open With costs you nothing and MDHero is free.
Where MDHero is straightforwardly ahead
It renders math and I do not. It edits and I deliberately do not. It reads on Windows and Linux and I never will. It runs back to macOS 12 where I need 14. It cleans up the escaped newlines that AI output arrives with, which is a small feature that solves a real irritation. And its source is MIT-licensed, so you can read exactly what it does — something you cannot do with mine at any price.
Where the difference is a design choice, not a score
MacMD Viewer is read-only and cannot be made to save. MDHero has View, Split and Edit modes with ⌘S. That is not a missing feature on my side; it is the product decision. An app you open to read a file your agent generated cannot overwrite that file if it has no way to write.
Whether that matters to you is a genuine question, not a rhetorical one. Some people want the typo fixed in the window where they saw it. Some people want the reading tool to be incapable of touching the source. There is no universal answer, and MDHero and MacMD Viewer picked opposite ones on purpose.
Version numbers, stated fairly
MDHero is at 0.2.8. MacMD Viewer is on its 1.6 line, on sale since March 2026. Pre-1.0 is the developer's own signal about maturity, and it deserves to be read as exactly that — not as a defect, and not as nothing.
The recommendation
Install MDHero if it runs on your Mac and you want to spend nothing, if you need math, editing, slideshows, or Windows and Linux builds.
Buy MacMD Viewer if your Mac is Intel, or if you want Markdown rendered in Finder with the spacebar, 12 document themes, and a developer paid to answer your email.
Related: MacMD Viewer vs Meva · vs Markdown Better View · vs QLMarkdown · all comparisons
Both apps render CommonMark-compliant Markdown with GitHub Flavored Markdown extensions including tables and task lists.
Frequently Asked Questions
Is MacMD Viewer better than MDHero?
MDHero is free, open source and actively developed, and it does things I do not: math, editing, Marp slideshows, Windows and Linux builds. Install it first. MacMD Viewer is the answer to two questions MDHero does not answer today — will it run on my Intel Mac, and can I read the file straight from Finder with the spacebar.
How much does MDHero cost?
MDHero costs Free (MIT licence). MacMD Viewer costs $19.99 one-time with no subscription.
Does MDHero support Mermaid diagrams?
Yes, MDHero supports Mermaid diagrams.
Can I use MDHero and MacMD Viewer together?
Yes. Many developers write in MDHero and use MacMD Viewer for reading and QuickLook preview. MacMD Viewer watches files live, so edits made in any other app appear instantly.
Does MDHero support Apple Silicon natively?
MDHero supports Apple Silicon natively. MacMD Viewer is also built with SwiftUI and runs natively on Apple Silicon.
Which is better for developers, MDHero or MacMD Viewer?
It depends on your workflow. MDHero is designed for previewing alongside your editor. MacMD Viewer is designed for reading. Open any .md file with rendered Mermaid diagrams, syntax highlighting, and a QuickLook extension. Most developers use both: an editor for writing and MacMD Viewer for reading.