Codeigniter is an open source web application. It occupies a very small amount of space in the memory and is most useful for developers who aim to develop simple and full featured dynamic web applications. Codeigniter is developed using PHP and depends on MVC architecture which has a simple and elegant framework. It has a high featured library.
Choosing an inappropriate PHP framework can create complications in the long run leading to prolonged development time and other concomitant problems. Yii Framework and CodeIgniter are arguably the two frameworks most widely preferred.