The SMS HTTP interface is an application hosted on a server that listens for HTTP requests containing SMS message data. It processes the HTTP requests and their associated SMS message data and sends the required SMS messages for onward delivery. The SMS HTTP interface sends back an HTTP response containing information about the submitted SMS messages such as the message identifiers of the sent SMS messages.
The SMS HTTP interface also includes a callback application which sends back delivery reports. The callback application achieves this by sending HTTP callback requests to your HTTP server (which must return an appropriate response) in order for delivery reports to be received. The figure below illustrates the architectural setup.