Fat-Free Framework

As its name suggests, Fat-Free Framework is a super lightweight PHP microframework that wants to help you build dynamic web apps as quickly as possible. To do so, it includes a fully-featured toolkit, a mature code base, and a very simple approach to writing applications. The best thing about it is that getting started with the Fat-Free Framework is very straightforward, as you don’t need to go through complicated configurations or directory structures. 

Fat-Free Framework is an open-source web framework distributed under the GNU General Public License and hosted by GitHub and Sourceforge. The software seeks to combine a full featureset with a lightweight code base while being easy to learn, use and extend.