Markdown, explained simply

Markdown is plain text with a few simple marks, like # for a heading and ** for bold, that turn into real formatting when an app reads the file. You write the marks by hand. The app renders them. The file stays a plain text file the whole way through.

A Markdown file is just text. It opens in any editor, on any computer, and reads fine either way, marks and all. There's no proprietary format to get locked out of.

What the marks look like

You don't memorize a manual. A handful of symbols cover most of what people write. Here are three of them.

A heading starts with one or more # characters:

# Project notes
## Tuesday

That renders as a large title and a smaller subheading. One # is the biggest, ###### is the smallest. The number of hashes sets the level.

Bold and italic use asterisks around the words:

This is **important** and this is *a quiet aside*.

Two asterisks make the word bold. One makes it italic. The asterisks disappear when the file renders, leaving just the styled text.

A bulleted list is a dash and a space at the start of each line:

- Buy coffee
- Reply to Sam
- Ship the build

That becomes three bullet points. Swap the dashes for 1., 2., 3. and you get a numbered list instead.

Why write this way at all

It stays readable as raw text. Even with the marks showing, ## Tuesday and - Buy coffee read like what they are. A document in a binary format is gibberish once the app that made it is gone. A Markdown file never is.

It's portable. The same file opens in any text editor, moves between Mac and Windows without conversion, and pastes cleanly into a chat or an email. GitHub, Reddit, most note apps, and plenty of AI tools already speak it, so a file you write in one place renders in the next. You picked a format, not a piece of software.

In Unmarked

Unmarked is a native Mac reader and editor for a single Markdown file. It handles the marks two ways, depending on what you're doing.

Read mode renders the document. Headings become titles, **bold** becomes bold, lists become bullets, and the marks themselves disappear. It's the finished page.

Write mode shows the source so you can edit it, and the syntax dims and reveals at your cursor. The marks stay out of your way while you write a paragraph, then sharpen into view on the line you're working, so you always know what a symbol is doing. A split mode puts both side by side, scrolling in sync.

Unmarked renders the everyday Markdown covered here and a good deal more: tables, task lists, fenced code blocks with a language label. A couple of less common pieces, footnotes and math, stay on screen as the plain text you typed.