App used: Marked 2


Code to include in .emacs file:

;; Getting emacs to use the 'Marked' app
(defun markdown-preview-file ()
  "run Marked on the current file and revert the buffer"
   (format "open -a /Applications/Marked\\ %s"
       (shell-quote-argument (buffer-file-name))))

Create a key-binding to open emacs markdown file in Marked:

(eval-after-load 'markdown-mode
  '(define-key markdown-mode-map (kbd "C-x p") 'markdown-preview-file))

What’s cool is that as you write and save changes, they’re immediately updated in the Marked preview, with a dash at the most recent change

If you want to use different templates, you can get them at Marked 2 templates by Brett Terpstra