Help with DHTMLX spreadsheet

Looking at the spreadsheet specifically, it really looks like it's built to manage the database connection and communication with the view on its own. You could probably load a spreadsheet into a CI view and route data to it via CI controllers, but unless you find someone who has already done it, you're probably going to have to deal with a lot of trial & error before you can get it working.

Bonfire

Practical CodeIgniter 3
CodeIgniter Testing Guide