CodeIgniter is an open source, lightweight, fast, application framework based on PHP with the huge Community of Users.

CodeIgniter’s full-range of libraries is handy to access the database, send an email, validate form data, maintain the session, manipulate an image, and work with XML-RPC data.

As additional libraries are loaded upon request, keeping the base system is lean and fast.
By providing a simple interface and logical structure, it reduces the bulk of the code needed for a task.

Build on the Model-View-Controller pattern CodeIgniter set apart application logic from presentation, obviating the need of template engine.

Employing segment-based approach it generates search-engine-friendly URLs.

CodeIgniter extended by using libraries, helpers, or through class extensions or system hooks.