Markdown It

Markdown-it is a pluggable Markdown parser for JavaScript with very effective syntax plugin support, maintained by the Nodeca team led by Vitaly Puzrin. The parser follows a specification-first design philosophy, implementing the CommonMark specification as its baseline with optional extensions that maintain strict spec compliance when enabled. The architecture separates parsing into two phases, with a block-level parser handling headings, paragraphs, blockquotes, lists, code blocks, and tables, and an inline-level parser processing emphasis, links, images, autolinks, and code spans within block content. Built-in features include typographic replacements converting plain text punctuation to smart quotes, ellipses, and dashes, linkify for automatic URL detection and conversion to clickable links, and configurable HTML escaping and sanitization for safe rendering of untrusted input. The syntax highlighting integration supports highlight.js, Prism, Shiki, and custom highlighters through a callback API. The plugin ecosystem is the killer feature, with official plugins covering emoji rendering with twemoji integration, subscript and superscript notation, inserted and marked text, footnotes with multi-paragraph support, definition lists, abbreviations, custom containers for admonition-style blocks, and task lists with checkboxes. The renderer rules can be overridden per token type for complete control over HTML output, and the token stream is accessible for AST manipulation and custom rendering targets. The parser powers documentation sites built with VuePress, VitePress, Docusaurus plugins, and many content management systems. MIT licensed. Copyright 2014-2026 Vitaly Puzrin, Nodeca.