What is the best IDE for development with CI

What about phpstorm? https://www.jetbrains.com/phpstorm/

the best ide with CI is Sublime text that is the best IDE for that

I like Netbeans, but believe that experimenting with a few IDE's will give you an Idea of what is right for you. Everyone has different taste, skill level, and need of different features in an IDE.

Over the years, I have used Netbeans / Eclipse and PHPStorm from my previous company they paid for subscription. I knew they are all good and up to personal preference
, I found Netbeans seemed to hang after a while when you run many apps in the dev machine and it is quite memory hungry!. I love eclipse that you can find almost every extra plugins for your development needs.

I recently use Visual Code ( free from Microsoft) and it is light and the power is endless. I can work on remote file / Git management / access to mySQL and I am not sure
what it is not capable of. You can use it for PHP / Python / NodeJS so on. Just look for extensions and you can find what you want.

Try them all out and decide what is best for your need! I dont think there is perfect IDE but best IDE for your need.

Regards

Used to use Editplus, but now for 5-6 years, Sublime with couple of helpful plugins.

I'm another who uses Sublime Text 3, it's also fantastic for HTML and CSS as well as PHP

I've tried Programmer's Notepad, Notepad++, Visual Studio Code, Atom, Sublime 3 since the past few years with VSC + Atom being used heavily recently just because I couldn't afford to pay for ST3 (although it's free to use but the nagging screen will get to your nerve somehow). I'm not going to talk about the later but I will let you know my personal preference.

Fastest Boot = ST3
Useful Extensions/Packages = ST3
Best Friendly Interface = ST3
Git Support = VSC / Atom
CI3 Snippet = All
UIKit3 Snippet = All but auto-complete works best in ST3 compared to VSC and Atom.
Themes = All but I love Atom's dark UI (I used that on my ST3 as well because it's better than Monokai which is my 2nd choice).

Other important mentions = IntelliSense on VSC. I'm using PHPLinter on ST3 so whenever I forgot some lousy closing bracket or ; it will show a red dot besides the line number for easy debugging. Some color picker UI on ST3 to work with HTML/CSS.

Honestly, $80 is quite expensive for hobbyist but if you make money from your apps, that's just a small fraction you should invest and I can guarantee you it's worth you money. There are keys circulating around but I don't use it because I always support the developers. I'd rather go through the nagging than destroying the developers' income. I hope if my next project is a success, I'll certainly buy a few ST3 licenses. (lol, free advertisement)..

I use an online IDE (Cloud9). Almost everything is already installed, PHP, Apache... It works everywhere on every computer / OS with an internet connection, and premium accounts support collaborative developments. 

For nothing in the world I would come back to an installed IDE on my computers. 

For those who are interested, here is how to install CodeIgniter on a Cloud9 server :https://www.lucidar.me/en/codeigniter-3-1-9/install-codeigniter-on-ubuntu/

There is also Codeanywhere that seems great, but I didn't try.

I use Codelobster IDE - http://www.codelobster.com/codeigniter.html