What is Markdown?
Markdown is a lightweight markup language created by John Gruber in 2004. It lets you write formatted text using plain-text syntax that is easy to read even without rendering. Markdown files use the .md or .markdown extension and are converted to HTML for display.
Markdown was designed with one guiding principle: a Markdown-formatted document should be publishable as-is, as plain text, without looking like it has been marked up with tags or formatting instructions. This makes it ideal for documentation, README files, and any content that needs to be readable in both raw and rendered forms.
Common Markdown Syntax
Headers use hash marks: # H1, ## H2, through ###### H6. Bold text is wrapped in double asterisks **bold**, italic in single asterisks *italic*. Links use [text](url) and images use . Unordered lists use dashes - item, ordered lists use numbers 1. item. Code blocks are fenced with triple backticks. Blockquotes use > prefix.
Where Markdown is Used
Markdown is used across the software industry. GitHub renders README.md files on every repository. Documentation tools like MkDocs, Docusaurus, and Jekyll use Markdown as their primary content format. Blogging platforms including Ghost, Hugo, and Gatsby support Markdown natively. Messaging apps like Slack and Discord use Markdown-like syntax for formatting. Jupyter notebooks use Markdown for narrative text cells alongside code.
How to Use This Previewer
- Type or paste Markdown in the left editor panel.
- The right panel renders the HTML preview in real time as you type.
- Use the toolbar buttons to insert formatting (bold, italic, code, links, headings, lists, blockquotes).
- Click Copy HTML to copy the rendered HTML output, or Copy Markdown to copy the raw source.
Frequently Asked Questions
What is Markdown?
Markdown is a lightweight markup language that uses plain-text formatting syntax. Created by John Gruber in 2004, it is designed to be converted to HTML and other formats. Markdown is widely used for documentation, README files, forum posts, and static site generators because it is simple to learn and readable even without rendering.
How do I make text bold in Markdown?
Wrap the text in double asterisks: **bold text** renders as bold text. You can also use double underscores: __bold text__. For italic, use single asterisks or underscores: *italic* or _italic_. Combine them with triple asterisks for bold italic: ***bold italic***.
Can Markdown include images?
Yes. Use the syntax . The alt text describes the image for accessibility and is displayed if the image fails to load. You can also add an optional title: . For more control over sizing, you can fall back to inline HTML <img> tags.
What is GitHub Flavored Markdown?
GitHub Flavored Markdown (GFM) is GitHub's extension of standard Markdown. It adds support for tables, task lists with checkboxes, strikethrough text (~~deleted~~), fenced code blocks with syntax highlighting, and automatic URL linking. GFM is the de facto standard for README files and documentation on GitHub.
How do I create a table in Markdown?
Use pipes and dashes to create tables. The first row is the header, the second row defines alignment with dashes, and subsequent rows are data. Example: | Name | Age | followed by |------|-----| and data rows. Colons in the separator row control alignment: :--- for left, :---: for center, ---: for right.
Is Markdown the same as HTML?
No. Markdown is a simpler syntax that gets converted to HTML. Markdown covers common formatting needs (headings, lists, links, images, code) with minimal syntax. HTML is a full markup language with complete control over page structure and semantics. Most Markdown renderers allow inline HTML within Markdown for cases where Markdown syntax is insufficient.