Markdown Preview

Features

• Live side-by-side preview
• Headings, emphasis, lists, tables, blockquotes and code
• Task lists, links and images
• HTML export
• Raw HTML in the source is escaped, not executed

How to use it

1. Type or paste Markdown on the left.
2. The preview renders as you type.
3. Copy the generated HTML, or download it as a file.
4. Use the sample to see the supported syntax.

Markdown's many dialects

Markdown was written by John Gruber in 2004 with a deliberately loose specification, which led to incompatible implementations. CommonMark was created in 2014 to pin down the ambiguities, how many spaces a nested list needs, what happens with mismatched emphasis markers, how to handle a list item containing a blank line. Most modern renderers follow CommonMark, but not all agree on the extensions.

GitHub Flavored Markdown adds the features most people now assume are standard: tables, fenced code blocks with language hints, strikethrough, task lists and automatic URL linking. None of those are in the original Markdown. This renderer implements the common subset of GFM, which covers what documentation and README files actually use.

One security point worth knowing. Original Markdown deliberately passes raw HTML straight through, which is convenient and dangerous, a Markdown file from an untrusted source can contain a script tag. Renderers that accept user content must sanitise the output, and many CVEs have come from doing this incompletely. This tool escapes HTML in the source rather than passing it through, which loses a little flexibility and eliminates the entire risk category.