Callbacks
The figure below illustrates the lifecycle of a call and shows where both callbacks and REST API calls are located or can be made.
The Incoming Call Event (ICE), is triggered when the Sinch platform receives an incoming call. The event can trigger a REST request to your application backend. Your reply instructs the Sinch platform how to act. The response can include an object written in the Sinch Voice Application Markup Language (SVAML) and it can, for instance, instruct Sinch to play a number of IVRs and then connect the call to the PSTN. The Answered Call Event (ACE) is triggered when the call is answered and can render an additional REST call to your platform. SVAML instructions can again be provided in the response to the ACE event. Finally, the Disconnected Call Event (DiCE) is triggered when the call is disconnected. Between ACE and DiCE, it's legal to call the ManageCall REST API which is part of the Calling API, to instruct the call to be hung up and/or to play an Interactive Voice Response (IVR) during the conversation.