What is Markdown?
Markdown is a lightweight markup language created by John Gruber in 2004. It lets you write plain text with simple formatting syntax that converts to valid HTML. The goal was to make writing for the web as readable and writable as possible — the source document should look good even as plain text.
Common Markdown syntax
Headings are created with # symbols (one to six). Bold text uses **double asterisks**, italic uses *single asterisks*. Links are written as [text](url). Code blocks use triple backticks. Unordered lists use - or * prefixes, and ordered lists use numbers. Blockquotes begin with >.
Use cases
Markdown is used for README files on GitHub, documentation sites (like MkDocs and Docusaurus), static site generators (Jekyll, Hugo, Eleventy), blog posts, forum posts (Reddit, Stack Overflow), and note-taking apps (Notion, Obsidian, Bear). Once you learn the basics, you can write formatted content much faster than using a WYSIWYG editor.
How this tool works
This previewer parses your Markdown entirely in the browser using a custom JavaScript parser. There is no server involved — your text never leaves your device. The rendered HTML updates live as you type, and you can copy the generated HTML output with one click.