1. A method comprising: receiving an authentication request from a user device at a home subscriber server (HSS)-front end (FE) of a mobile network; accessing a user data repository (UDR) of the mobile network from the HSS-FE to identify user data and subscribe to notifications regarding changes to that user data; receiving a request at the HSS-FE for the user device to access a network application function of a non-internet protocol multimedia subsystem (IMS) data provider; accessing the UDR of the mobile network from the HSS-FE to determine authentication information for the user device; and authenticating the user device to the non-IMS data provider based on the authentication information.