CommonMark.c 0.28.2

Cmark is a CommonMark (derived from MarkDown) reference implementation in C. (An implementation in JavaScript is also available). It provides parsing and HTML or XML transformation. An intermediate AST representation of documents can also be augmented. On performance it's on par with sundown. There's a C99 compliant libcmark and a command-line cmark tool included.

CommonMark.js 0.27.0

CommonMark.js is a reference implementation for JavaScript. (And a C version available as well). It parses the document format, provides a modifyable abstract syntax tree, and can render to HTML, XML, or per DOM. It's also readily available as NPM/io.js module.

mikidown 0.3.6

MikiDown is a note taking application utilizing MarkDown/CommonMark. It allows editing with a live WYSIWYG preview, can switch between Edit/View/LiveEdit modes. It centralizes all notes, but provides notebook/tab support, page crosslinking, can import from plain text, export to HTML or PDF with customized stylesheets, and includes spellchecking.