CAS splits the application into the business part and the interface thin-client. The business part is in fact the application, with unlimited number of interfaces. The business part communicates with the thin client (called Concept Client) by using the concept:// protocol or websockets (ws:// and wss://). 

The synchronization is achieved by using a messaging service able to exchange messages both over the cloud (Internet) and over the server itself. 

Except the latency compensation code, no piece of Concept code will be executed on the client. Instead, all the events and user data input will be done with the client (native or HTML5 browser). Concept Application Server has a relatively small resemblance with the traditional HTTP servers, because instead of typical "touch and go" scripts (a script is run for every user event), the application is always active ensuring a better end-user experience. Can be regarded as a bi-directional protocol while HTTP is request-based (unidirectional).