How to open or create Markdown files in Mardo

Mardo works with ordinary Markdown files. Open one with File → Open…, drag it onto Mardo, open it from Finder, or pass its path to the optional mardo Terminal command. There is no vault, import step, account, or proprietary workspace.

Open an existing file

1. Choose File → Open… or press Command-O.

2. Select a Markdown file.

3. Choose Open.

Mardo supports files ending in .md, .markdown, .mdown, .mkd, and .mkdn. You can also double-click an associated file, drag a file to Mardo, or select it in Finder and press Space for Quick Look.

Create a file

1. Choose File → New or press Command-N.

2. Add content.

3. Choose File → Save or press Command-S.

4. Pick an ordinary filesystem location and Markdown filename.

The saved Markdown bytes are the document. Mardo does not create a surrounding project database.

Open from Terminal

In Mardo, choose Help → Command-Line Tool… to install the optional command. Then run:

mardo README.md
mardo notes.md project-plan.markdown

Relative paths use Terminal's current directory. A missing path without an extension receives .md; Mardo does not create that file until you save the new document.

Current as of September 7, 2026.