Cloud telephony server with good API?

Question

API

There is a task: to initiate a call programmatically, when answering, play the message, and then switch to the operator; at the same time, while the operator is communicating, it is necessary to initiate a similar call in the background and, when the operator completes the communication, connect the call from the background to it; the cycle can be repeated 15-20 times; 15-20 operators can communicate at the same time; there can be 2-3 calls in the background at the same time.
Please tell me:
1. A cloud telephony service whose API allows you to do the above
2. If there is no cloud service, then what query to google for in order to understand how to set up this system yourself from scratch (using your own telephony server, which, preferably, is rented from data center)

Answer 1

perhaps all this can be done with voximplant scripts, if not, then it can be done with scripts (js / lua / java, etc) freeswitch.
Read this to get started https://www.bionicspirit.com/blog/2009/02/20/tips-...
you will have to think further.

Answer 2

If there are programmers, then you can try the service from ringcloud.ru
They have an API. =)