GitHub Flavored Markdown is described as 'GitHub uses "GitHub Flavored Markdown," or GFM, across the site--in issues, comments, and pull requests. It differs from standard Markdown (SM) in a few significant ways, and adds some additional functionality' and is an app. There are five alternatives to GitHub Flavored Markdown for a variety of platforms, including Linux, Mac, Windows, Web-based and Self-Hosted apps. The best GitHub Flavored Markdown alternative is MyST Markdown, which is both free and Open Source. Other great apps like GitHub Flavored Markdown are Textile, PHP Markdown, MarkMyWords and ReAdABLE Human Format.