A communications system may include a plurality of communications devices connected together in a network and having a plurality of user accounts associated therewith. At least one of the communications devices may process requests using an HTTP client application associated therewith. The system may also include an application server for accessing the user accounts via the HTTP client application, and an HTTP server for interfacing the HTTP client application with the application server. The HTTP server and the HTTP client application may format requests to be communicated therebetween in an HTTP format, and each may provide additional state information with the HTTP formatted requests recognizable by the other for authentication purposes. Furthermore, the HTTP client application may request a first universal resource locator (URL) from the HTTP server for accepting work requests from the application server, and a second URL different from the first for responding to work requests.