CodeIgniter is the MVC framework used for the PHP coding. Also, validation criteria for (database) table fields are the provided by CodeIgniter, and signatures for others are derived from those.

I used CodeIgniter while working at KHM Travel Group. It was the system we used for an affiliate-based site called TravSearch, which I later replaced with a WordPress Multisite. I developed a .csv upload form to transfer all the information from the affiliate table of CodeIgniter to the user and options tables in WPMU.

Integrate with some code-igniter low-level modules through composer.

It is super easy to do things in PHP using codeigniter. Used the MVC architecture to create different types of pages and modules.

Old stack framework