CodeIgniter is a powerful PHP framework with a very small footprint, built for developers who need a simple and elegant toolkit to create full-featured web applications.
A breakdown of CodeIgniter features
CodeIgniter consistently outperforms most of its competitors.
Simple solutions over complexity
CodeIgniter encourages MVC, but does not force it on you.
We take security seriously, with built-in protection against CSRF and XSS attacks.
The CodeIgniter User Guide comes with the download. It contains an introduction, tutorial, a number of “how to” guides, and then reference documentation for the components that make up the framework.
Nearly zero configuration
Much of the CodeIgniter configuration is done by convention, for instance putting models in a “models” folder. There are still a number of configuration options available, through scripts in the “config” folder.