A system for dynamically integrating and synchronizing a plurality of software applications of an end user as part of a telephonic communication between the end user and a third party managed and handled by a hosted VoIP PBX includes a client side integration proxy having (i) an API for communicating and exchanging data with the software applications and (ii) memory cache dedicated to storing information about the telephonic communication handled and managed by a hosted VoIP PBX, wherein the client side integration proxy assigns a record in the memory cache for storing information about the telephonic communication and enables the software applications periodically to access and dynamically update, modify, or add to the record as the information about the telephonic communication is updated or changed by other software applications and by the end user.