Why convert Markdown to HTML?

Markdown is great for writing, but web browsers render HTML. Converting Markdown to HTML is essential when publishing blog posts, creating email newsletters, embedding content in web pages, or generating documentation. The resulting HTML is clean, semantic, and ready to style with CSS. Most static site generators and CMS platforms perform this conversion automatically, but having an online tool lets you preview and copy the HTML directly.

Common use cases for Markdown to HTML conversion

Writers and developers convert Markdown to HTML for CMS publishing, email templates, static site content, and documentation sites. It is useful when previewing how a README or wiki page will look when rendered, when pasting formatted content into a WYSIWYG editor, or when generating HTML snippets for embedding in applications that do not have built-in Markdown rendering.

Markdown syntax to HTML mapping

The conversion follows well-defined rules. # Heading becomes <h1>Heading</h1>. **bold** becomes <strong>bold</strong>. *italic* becomes <em>italic</em>. [text](url) becomes <a href="url">text</a>.  becomes <img alt="alt" src="src" />. Unordered lists with - produce <ul><li> elements. Fenced code blocks with ``` produce <pre><code> with optional language classes for syntax highlighting. Block quotes with > produce <blockquote> elements.

// JavaScript — Markdown to HTML with marked
import { marked } from 'marked';
const md = '# Hello\n\nThis is **bold** and *italic*.';
const html = marked.parse(md);
// <h1>Hello</h1>\n<p>This is <strong>bold</strong> and <em>italic</em>.</p>

# Python — Markdown to HTML
import markdown
md = '# Hello\n\nThis is **bold** and *italic*.'
html = markdown.markdown(md)
print(html)
# <h1>Hello</h1>\n<p>This is <strong>bold</strong> and <em>italic</em>.</p>

Markdown flavors compared

Several Markdown flavors exist beyond the original specification. CommonMark is the standardized specification that removes ambiguities from the original. GitHub Flavored Markdown (GFM) adds tables, task lists, strikethrough, and autolinks. MultiMarkdown adds footnotes, citations, and metadata. Pandoc Markdown supports academic features like definitions, superscripts, and LaTeX math. This converter supports CommonMark and GFM, covering the vast majority of Markdown content in use today.

Security considerations for rendered HTML

When converting user-generated Markdown to HTML, always sanitize the output before inserting it into a web page. Markdown allows raw HTML blocks, which means a user could embed <script> tags or event handler attributes that execute JavaScript. Libraries like DOMPurify can strip dangerous elements while preserving safe formatting. For trusted content like your own documentation or blog posts, sanitization is less critical but still a good practice.