You set up an Inbound Service on a telephone number or SIP address to run one of your applications when it receives an inbound call.
Developer accounts include use of a range of dedicated test telephone numbers.
Each Inbound Service runs either a REST or UAS application. Quickstart guides are included to get you started writing applications.
Inbound (PSTN and SIP) calls are free (you just pay the platform rate).
For purchased telephone numbers that support SMS messaging the Inbound Service notifies a supplied URL when it receives a message.