Mdown

Mdown is a focused, native-feeling Markdown editor for macOS. It pairs Monaco's fast editor with a simple, optional preview so writing stays at the centre of the app.

Download

Download the current macOS installers from the Mdown Releases page: choose Apple Silicon for M-series Macs or Intel for older Intel-based Macs.

First launch of release version

If you download Mdown from GitHub Releases, macOS may show a warning that the app is from an unverified developer (or that Apple could not check it for malicious software).

This happens because Gatekeeper applies extra checks to apps downloaded from the internet, and apps distributed outside the Mac App Store can trigger this warning when they are not notarized in a way macOS expects.

To open Mdown anyway:

1. In Finder, locate Mdown in Applications.
2. Control-click (or right-click) the app and choose Open.
3. Click Open again in the confirmation dialog.

If that option does not appear:

1. Try opening Mdown once so the warning appears.
2. Open System Settings → Privacy & Security.
3. Scroll to the security section and click Open Anyway for Mdown.
4. Confirm by clicking Open.

Features

• Open and edit Markdown files in dedicated windows.
• Monaco editor with Markdown-aware editing, a clean TextEdit-inspired interface, and configurable font size.
• Toggleable rendered preview with proportional scroll synchronisation.
• YAML-style frontmatter and {{key}} placeholders for reusable document values.
• Optional AI writing assistant: chat about a document or selection, improve/rewrite selected text, and customise prompts.
• Light and dark modes, persistent preview/font settings, and optional Google Font support.

Keyboard shortcuts

• ⌘N — new document window
• ⌘O — open a Markdown file in a new window
• ⌘S / ⇧⌘S — save / save as
• ⇧⌘P — toggle preview
• ⇧⌘I — toggle the AI sidebar
• ⌘+ / ⌘- — change editor font size

AI configuration

Choose Edit → Edit Config… to edit Mdown's local configuration file. Add your API key there to enable the assistant, and optionally add or change the saved writing prompts. The configuration stays on your Mac and is excluded from Git.

Development

Requires Node.js and macOS.

npm install
npm test
npm start

Create installers after the test suite passes:

npm run package:mac:intel    # Intel Macs
npm run package:mac:silicon  # Apple Silicon Macs
# or build both
npm run package:mac

The DMGs are written to dist/ as architecture-specific files.

To test, package, tag, push, and publish a release in one step, first commit any application changes, then run:

./scripts/release.sh 1.0.1

The script requires an authenticated GitHub CLI session and publishes the Intel and Apple Silicon DMGs to GitHub Releases.

Support the project

If Mdown is useful to you, you can support its development at Buy Me a Coffee.