Markdown to HTML

From Markdown to rendered HTML

Markdown is a shorthand for writing formatted text in plain characters, then converting to HTML for display. A converter reads the Markdown rules, headings with #, emphasis with asterisks, links in brackets, and emits the equivalent tags. It is how READMEs, comments, and docs become web pages.

Example

Markdown:

# Title

A paragraph with **bold** and a [link](https://ex.com).

- one
- two

Resulting HTML:

<h1>Title</h1>
<p>A paragraph with <strong>bold</strong> and a
<a href="https://ex.com">link</a>.</p>
<ul><li>one</li><li>two</li></ul>

Flavors are not one standard

There is no single Markdown. Original Markdown, CommonMark, and GitHub Flavored Markdown differ. Tables, strikethrough, task lists, and fenced code with language hints are GFM extensions that plain Markdown does not define. Content that renders on GitHub may come out as literal text in a stricter parser, which is the most common "why does this look wrong" moment.

The sanitization question

Markdown allows raw HTML inline, so a document can contain a <script> tag. If you render untrusted Markdown and pass that HTML straight to a page, you have an XSS hole. Any converter handling user input must sanitize the output. For the reverse direction, see HTML to Markdown.

FAQ

Why do my single line breaks disappear? Standard Markdown treats a single newline as a space; you need two trailing spaces or a blank line to force a break. GFM is more lenient.

How do I get a code block with a language? Fence it with triple backticks and a language name. That is a GFM feature that adds a class for syntax highlighting.