Markdown Preview
Understand Markdown Preview
This preview renders Markdown to HTML as you type, so you can see how a README or a long comment will come out.
How it works
The Markdown is converted by a set of rules applied in order: fenced code blocks first, so their contents are escaped and left alone, then headings, blockquotes, rules, lists, inline code, bold, italic, and links. The resulting HTML is filtered against an allow-list — headings, paragraphs, lists, code, pre, strong, em, blockquote, hr, br, and links — and every attribute except an http, https, or mailto href is dropped, so raw HTML in the source cannot execute.
When to use it
- Checking a README's headings and code fences before pushing it.
- Seeing whether a long issue body or comment will render the way you intended.
- Converting a Markdown snippet into HTML you can paste into a CMS or an email.
- Testing whether a list or a nested code block is written correctly.
Watch out for
- This is a CommonMark subset, not GitHub Flavored Markdown. Tables, task lists, strikethrough, footnotes, and images are not rendered — their source text shows through instead.
- Underscores inside a word are read as emphasis, so snake_case_name renders with the middle word italicized. CommonMark deliberately does not do this; wrap identifiers in backticks.
- Nesting is shallow. A list inside a blockquote, or an indented sub-list, will not come out the way a full parser produces it.
- Raw HTML in the source is reduced to its text content by the sanitizer. That is intentional, and it makes this preview stricter than GitHub, which permits a limited set of tags.
Not the right tool for: Confirming exactly how GitHub will render a file. GitHub layers its own extensions and its own sanitizer on top of CommonMark; for a byte-exact check, push to a branch and look.
Frequently Asked Questions
Which Markdown syntax is supported?
CommonMark spec: # headings (1-6 levels), **bold**, *italic*, `inline code`, ```fenced code blocks```, [links](url), , - unordered lists, 1. ordered lists, > blockquotes, --- horizontal rules, and | table | syntax.
How do I preview a GitHub README?
Paste your README.md content into the editor. GitHub uses a strict CommonMark parser with additional GFM (GitHub Flavored Markdown) extensions for task lists, tables, and strikethrough. The preview closely matches GitHub's rendering.
Can I export the rendered HTML?
Yes — click "Copy HTML" to get the rendered HTML output. This is useful for pasting formatted content into email clients, CMS systems that accept HTML input, or HTML email templates.
How to Use Markdown Preview
- Paste or type your input in the input area above.
- The tool processes your input automatically or click Run.
- Copy or download the result using the action buttons.
- Use Ctrl+Enter to run quickly from the keyboard.