Systems, devices, and methods described herein provide protocol endpoints that execute locally within private networks and perform a set of transport-related operations specified an application-layer protocol to which messages exchanged between local applications executing within private networks and cloud applications executing in cloud computing systems conform. However, systems, devices, and methods described herein also leverage computing resources of the cloud by having the cloud applications (rather than the protocol endpoints) perform a second set of operations specified by the application-layer protocol. By functioning in this manner, systems, devices, and methods described herein facilitate real-time bidirectional communication flow between local applications executing within private networks and cloud applications without exposing the private networks to the public Internet and without using a VPN (thereby avoiding the problematic overhead of a VPN) with respect to real-time communications.