How to implement server side for mobile chat?

Question

Mobile development

Hi all.
I want to create a mobile chat with the ability to send messages and pictures. The server part will be in PHP. Google writes that it is necessary to use sockets, but I did not find normal examples of the implementation of sockets in PHP. Is it too bad if I implement the back end as a web api? Do you have ready-made developments or tips on how to organize all this better?
PS I would not like to use XMPP, phpDaemon.

Answer 1

GCM is not suitable?