The uberfast file & Markdown editor

A fast, free Markdown editor for Mac

Plain Markdown that formats itself as you type, JSON and YAML as searchable trees, super comfortable DIFF view between any two files, code syntax highlight, VIM mode, diagrams & maths formula support, and much more.

built by developers, for developers

Free. Version 1.1.1, 11.3 MB. For macOS 12 or later, on Apple silicon and Intel.

See what it does
MMDZ in its dark theme, showing a Markdown file called Release notes in live preview: a heading, a paragraph with bold, italic and highlighted words, a checklist, a table of shortcuts and a TypeScript code block, all rendered in place, beside a sidebar of files in a Notes folder.
Light and dark themes

What is MMDZ?

MMDZ is an uber-fast, minimalist, offline, and free Markdown editor and viewer for macOS, made by Metamindz in London.

It easily becomes your day-to-day text files editor, as it supports most file formats, including syntax highlighting for code and live previews for Markdown.
We also added a very convenient MD editor, structured YAML and JSON file browser (+ built-in search & tree view), and a proper DIFF viewer between any two files.
We built it for ourselves and are now sharing it with the world. Hence, it is completely free, requires no registration, and has no analytics, telemetry, or anything like that.

Price
Free. No subscription, trial or in-app purchase
Download
11.3 MB disk image
Requires
macOS 12 Monterey or later
Runs on
Apple silicon and Intel, natively
Version
1.1.1, released 26 September 2026

Markdown that formats itself as you type

Headings, bold, lists, tables, task lists, maths and diagrams render in place. The Markdown syntax comes back only on the line you are editing, and the file on disk stays plain Markdown.

The same file in Live Preview with line numbers: the headings, checklist and table are formatted, and the Markdown syntax is hidden.
The Release notes file in Source view: the raw Markdown in a monospaced font with line numbers, including the hash signs, asterisks and table pipes.

Drag the line: towards the bottom right for the Source, back up for Live Preview.

Three views of every document

  • Live Preview, formatted as you typeOption Command 1
  • Source, the raw Markdown, monospacedOption Command 2
  • Reading, fully rendered and read-onlyOption Command 3

Command Slash cycles through them. Type Slash at the start of a line for the block menu.

Supported Markdown

  • CommonMark
  • GitHub Flavoured Markdown
  • Tables
  • Task lists
  • Strikethrough
  • Footnotes
  • Autolinks
  • Definition lists
  • ==Highlights==
  • Superscript and subscript
  • [[Wiki links]]
  • YAML front matter
  • KaTeX maths
  • Mermaid diagrams
  • Syntax-highlighted code

JSON and YAML you can actually read

Open any JSON or YAML file as a collapsible tree. Search keys and values, with regular expressions if you want them, filter down to the matches, and copy exactly the part you need.

  • Copy a value, the whole branch as JSON, its JSONPath, or its JSON Pointer (RFC 6901).
  • JSON with comments and trailing commas opens fine, and a broken file still shows everything that can be read.
  • YAML anchors and aliases show as badges. Multi-document files, tags and block scalars all work.
  • Show in source jumps to the exact spot in the text. Format, minify or sort the keys of any JSON file.
  • Files over 3 MB open in Source view first, so they appear straight away, with the tree one click away.
A JSON file, order.json, open as a collapsible tree, with a search for “price” highlighting the three matching keys and buttons to copy a value, copy as JSON, copy a pointer or show it in the source.
Two versions of an onboarding guide compared side by side, with changed lines tinted red and green and the exact words that changed highlighted.

Compare any two files

Drop two files on a comparison tab to see every change line by line, with the exact words that changed highlighted. Switch between side-by-side and unified views, and copy the result as a standard patch.

  • Works with any text files, not only Markdown.
  • Unchanged lines fold away, git-style, and open up when you need them.
  • Ignore whitespace or case, swap the sides, and jump between changes with Command G and Shift Command G.
  • Or start from an open file: Compare This File With…, or Compare With Saved Version.

New comparison Option Shift Command D

Everything else it does

The small things you reach for every day, each one a shortcut away.

  • The command palette searching for “export”, listing Export as HTML, Export as PDF, Expand All and Copy as Rich Text.

    Command paletteCommand K

    Type a few letters of a command, from Export as PDF to Expand All, and run it without reaching for a menu.

  • The Go to Line dialog over a TypeScript file, with “14:3” typed in to jump to line 14, column 3.

    Go to lineControl G

    Type 42, or 42:7 to land on a column. It works from any view, with line numbers in all of them.

  • Languages highlighted

    Code and text files open with syntax highlighting chosen by extension, line numbers and code folding.

  • Whole folders

    Open a folder as a file tree, jump to any file with Quick Open, or search every file in it at once.

  • Appearance settings: system, light or dark theme, a row of accent colours, typefaces and font size.

    Make it yours

    Light, dark or follow the system. Eight accent colours or one of your own, and your choice of typefaces, size and column width.

  • Print and PDF

    Prints just the document, never the app around it. Export as PDF or as a self-contained HTML file.

  • Vim mode

    Full modal editing for those who want it. Off by default; switch it on with ⌥⌘V.

  • Reading view of a Markdown document, with an outline panel on the right listing its headings.

    Reading view and outlineOption Command 3Option Command O

    Read a document fully rendered, with its headings listed beside it. Focus mode and typewriter scrolling for long writing.

  • Your default Markdown app

    One button in Settings makes MMDZ open every .md file, with separate ones for JSON and YAML.

  • Diagrams and maths

    Mermaid flowcharts and KaTeX equations, written as plain text, render right in the document as you type.

MMDZ keyboard shortcuts

The main ones, by menu. Press Shift Command Slash in the app to see every one of them.

General

Command paletteCommand K
Quick Open, the file switcherCommand T
SettingsCommand Comma
Show every keyboard shortcutShift Command Slash
Quit (asks about unsaved changes first)Command Q

File

New file / new windowCommand N/Shift Command N
Open file / open folderCommand O/Shift Command O
Save / Save As / Save AllCommand S/Shift Command S/Option Command S
PrintCommand P
Close tab / close windowCommand W/Shift Command W
Compare two filesOption Shift Command D

Edit

Find / find and replaceCommand F/Option Command F
Next / previous match (in a comparison: change)Command G/Shift Command G
Find in folderShift Command F
Go to lineControl G
Paste as Markdown / paste and match styleShift Command V/Option Shift Command V

Format

Bold, italic, inline code, highlightCommand BCommand ICommand EShift Command H
Insert linkCommand L
Heading level 1 to 6Command 1toCommand 6
ParagraphCommand 0
Bullet, numbered and task listShift Command 8Shift Command 7Shift Command 9
Quote, code block, tableShift Command Full stopShift Command CShift Command T
FootnoteShift Command 6
Format JSONOption Shift F

View

Live Preview / Source / ReadingOption Command 1/Option Command 2/Option Command 3
Cycle through the viewsCommand Slash
Expand all / collapse allOption Command Right bracket/Option Command Left bracket
Sidebar / outlineOption Command B/Option Command O
Line numbersOption Command L
Focus modeShift Command D
Zoom in / out / actual sizeCommand Equals/Command Minus/Shift Command 0

Tools

Vim modeOption Command V

Your files stay on your Mac

No account. No analytics. No telemetry.

Documents never leave your computer. The only connection MMDZ makes on its own is a check for updates, at most once a day, and you can switch it off in Settings → About → Updates. A document that links to images on the web loads those images, as any Markdown viewer does.

This website is a different matter: it asks for your email address before you download and keeps it in our CRM. The privacy policy says what we keep and why.

How to install MMDZ

  1. Download it

    Give us your email address, tick the box, and the 11.3 MB disk image downloads.

  2. Drag it to Applications

    Open the .dmg from your Downloads folder and drag MMDZ onto the Applications folder.

  3. Open it

    Open MMDZ from Applications or Launchpad. It is notarised by Apple, so macOS opens it without warnings.

Make it your default Markdown app

In MMDZ, open Settings → Files → Make MMDZ the default. Or select any .md file in Finder, press Command I, choose MMDZ under Open with and use the Change All… button. JSON and YAML have their own buttons in the same place.

Updates

Automatic, checked once a day, and MMDZ asks before installing. To check now, choose Check for Updates… in the MMDZ menu. To turn automatic checks off, go to Settings → About → Updates.

Uninstall

Quit MMDZ and move it from Applications to the Bin. Its settings live in ~/Library/Application Support/co.metamindz.mmdz/, which you can delete too.

Free, for every Mac

All it takes is your email address. No account, no trial, no card.

Version
1.1.1
Released
26 September 2026
Size
11.3 MB
Requires
macOS 12 or later, Apple silicon and Intel
Checksums
SHA-256

Pass it on

Send MMDZ to a friend

Know someone who lives in Markdown? Give us their work email and we will send them the link, with your note and your name on it.

Work addresses only. For anyone else, copy the link below.

It signs off the email: with ❤️ from you.

Up to 400 characters. No links: we add the download link for you.

One email, sent once. We do not add their address to anything.

Or copy the link

What they will get

MMDZ questions, answered

Something else? Email hello@metamindz.co.uk.

Is MMDZ really free?

Yes. There is no price, trial, subscription or in-app purchase, and no account to create. To download it, you give us your email address and accept the terms. That is all.

Why do you ask for my email address?

We email you the download link, which helps if you found MMDZ on your phone. If it is a work address, we may also send you the occasional email about MMDZ and other things we build, and one reply stops them. We do not send those to personal addresses such as Gmail or iCloud.

Which Macs does MMDZ run on?

Any Mac running macOS 12 Monterey or later. It is a universal app, so it runs natively on both Apple silicon and Intel Macs.

Is there a Windows or Linux version?

Not at the moment. MMDZ is macOS only.

Is MMDZ on the Mac App Store?

No. You download it from this page. It is signed with Metamindz Limited's Apple Developer ID and notarised by Apple, so macOS opens it without security warnings.

Does MMDZ change my files?

Only when you edit and save them. Documents stay plain text: live preview formats what you see on screen, not what is written to disk.

Does MMDZ send my documents anywhere?

No. MMDZ has no accounts, analytics or telemetry. The only automatic connection is the daily update check, which you can turn off. Documents that link to images on the web load those images, as any Markdown viewer does.

Can MMDZ open JSON with comments?

Yes. Comments and trailing commas are accepted, and a file with errors still shows everything that can be read.

Which file types can MMDZ open?

Markdown (.md, .markdown, .mdown, .mkd, .mdx), JSON (.json, .jsonc, .json5, .geojson, .topojson, .webmanifest) and YAML (.yaml, .yml) get their own views. Most other text and code files open with syntax highlighting for 143 languages.

Does MMDZ have Vim keybindings?

Yes, as an option. Vim mode is off by default; turn it on or off with ⌥⌘V.

How do I print a Markdown file or make a PDF?

⌘P prints the document on its own, without the app around it. File → Export as PDF… saves a paginated PDF directly, with no print dialog. Export as HTML saves a self-contained web page.

How do updates work?

MMDZ checks for updates once a day and asks before installing. Updates are cryptographically signed, and the app rejects anything not signed by Metamindz. You can switch automatic checks off in Settings → About → Updates.

Who makes MMDZ?

Metamindz Limited, a technology company in London, UK.

Made by Metamindz

Metamindz is a UK technical consultancy and software agency. We give startups and scale-ups flexible access to CTOs, technical leadership, recruitment and software development, and we give away tools like this one.

About MetamindzMore free tools