What is Markdown?

Markdown is a lightweight markup language created by John Gruber in 2004. Its goal was simple: let people write formatted documents in plain text that stays readable as-is, without the visual noise of HTML tags. A few unobtrusive symbols — a hash for a heading, asterisks for emphasis, a dash for a list item — are all you need, and a converter turns that plain text into well-structured HTML. Because the source is just text, it works in any editor, plays nicely with version control, and never locks you into a proprietary file format.

A Markdown preview tool shows you the rendered result while you write. You type Markdown on one side and see the formatted HTML output on the other, updating live. This instant feedback loop is what makes Markdown comfortable to learn and fast to work in — you catch a mistyped link or a broken list immediately, instead of after publishing. Markdown is now the default writing format for READMEs, technical documentation, static-site blog posts, GitHub and GitLab issues, and chat platforms like Slack and Discord.

How to Use the Markdown Preview

1. Type or paste your Markdown into the editor pane on the left.
2. Watch the preview pane on the right render the formatted result in real time.
3. Use the syntax reference below if you are unsure how to format something.
4. Refine your text until the preview matches what you want to publish.
5. Copy the finished Markdown into your README, documentation, blog post, or issue.

Supported Syntax

Why Write in Markdown?

The biggest advantage of Markdown is durability. A Markdown file is plain text, so it can be opened, read, and edited on any device, in any editor, decades from now — there is no dependency on a particular word processor or its file format. That same plain-text nature makes Markdown ideal for version control: Git can show a clean line-by-line diff of what changed, which is impossible with a binary document. Teams use this to review documentation changes the same way they review code.

Markdown is also fast to write. Because formatting is done with characters you are already typing, your hands never leave the keyboard to reach for a toolbar. The source stays readable even before rendering, so a Markdown file is useful as-is. The main thing to watch out for is whitespace: Markdown is sensitive to blank lines between blocks, and list items or code fences that are not separated correctly can render in surprising ways. The live preview is the quickest way to spot and fix those issues.

Frequently Asked Questions