What is CodeIgniter?

CodeIgniter is an open source and powerful framework used for developing web applications on PHP. It is loosely based on MVC pattern and similar to Cake PHP. CodeIgniter contains libraries, simple interface and logical structure to access these libraries, plug-ins, helpers and some other resources which solve the complex functions of PHP more easily maintaining high performance. It simplifies the PHP code and brings out a fully interactive, dynamic website at a much shorter time.