CodeIgniter is an open source rapid development web application framework, for use in building dynamic web sites with PHP. Its goal is to enable [developers] to develop projects much faster than writing code from scratch, by providing a rich set of libraries for commonly needed tasks, as well as a simple interface and logical structure to access these libraries.

CodeIgniter is loosely based on the popular Model-View-Controller development pattern. CodeIgniter is most often noted for its speed when compared to other PHP frameworks. In a critical take on PHP frameworks in general, PHP creator Rasmus Lerdorf spoke at frOSCon in August 2008, noting that he liked CodeIgniter “because it is faster, lighter and the least like a framework.