.md

What is a .md file?

Markdown is a lightweight text formatting syntax — headings with #, bold with **, links with [text](url) — readable as both source and rendered output.

Safe format
Type Document
By John Gruber / Aaron Swartz
MIME text/markdown

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What is it

You're reading a README, editing documentation, or writing notes in Obsidian. The file is Markdown — a formatting syntax so simple that most people can read the raw source without knowing it's a markup language. Headings start with #, bold uses **, links are [text](url), and that's enough to write most documents.

John Gruber and Aaron Swartz designed Markdown in 2004, and it quietly conquered the developer world. GitHub READMEs, Reddit posts, Discord messages, Notion pages, Jekyll blogs, Stack Overflow answers, and most technical documentation are all Markdown. The format converts to HTML with zero friction, which is why it became the default for anything that lives between plain text and a fully formatted document.

Any text editor opens .md files. VS Code has built-in Markdown preview. Obsidian and Typora ($15) provide polished editing experiences. For simple documents, you don't need a special editor at all — Markdown's entire point is that the source text is human-readable. If your document needs tables, footnotes, or complex layouts, most Markdown flavours support them with slight syntax extensions.

Technical details
Full Name
Markdown
MIME Type
text/markdown
Developer
John Gruber / Aaron Swartz
Magic Bytes
N/A
Safety
.md is a known, safe format.
What opens it
Any text editor
FREE All
VS Code
FREE All
Obsidian
FREE All
Typora
$15 All
FAQ
What's the difference between MD and TXT?
Both are plain text. Markdown adds lightweight formatting syntax (headings, bold, links, lists) that can be rendered as rich text. A .txt file is just raw text with no structure.
How do I open an MD file?
Any text editor opens it as plain text. For rendered preview, use VS Code (built-in preview), Obsidian, Typora, or paste it into a GitHub repo. Most Markdown editors show the formatted result in real time.
What is Markdown used for?
Documentation (GitHub READMEs), note-taking (Obsidian, Notion), blogging (Jekyll, Hugo), and writing for any platform that supports it (Reddit, Discord, Stack Overflow). It is the lingua franca of developer writing.
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