Marko

See your Markdown document as it will look on Github

Screenshots

Hunter's comment

Marko is the markdown preview of your documents, you can check the display how it will look on Github. Side by side preview makes it easy to keep it checked what you are writing and how it looks.

Use Marko side-by-side with your favorite text editor to preview your Markdown documents as you write them. Marko automatically reloads documents when you save them.
Source

Link

https://itunes.apple.com/us/app/marko/id607997198?ls=1&mt=12