Write a CRM script

You need to write a small CRM script to aggregate applications from 4 of our sales sites. CRMs should have all the standard functions – operators, administrators, clients. Customers must be created exclusively through AJAX request. Since CRM will be on another domain, it is necessary to provide for the possibility of cross-domain requests to the CRM API. Operators should have their own rates, depending on the production rate should change automatically. Administrators can add new users and change all system settings. You also need a chat between operators with additional encryption in addition to SSL.