instant-markdown-x is a fork for instant-markdown-d. For VIM: https://github.com/NBUT-Developers/extra-instant-markdown.
instant-markdown-d is a small Node.js server that enables instant compilation and previewing of Markup files. A plugin can easily be written for any text editor to interface with it. One currently exists for VIm: https://github.com/suan/vim-instant-markdown
$ [sudo] npm -g install instant-markdown-x
|Action||HTTP Method||Request URL||Request Body|
|Refresh Markdown on page||PUT||http://localhost:<port>||<New Markdown file contents>|
<port> is 18474.