"Smart" telephone answering machine: what are the solutions?

Question

Telephony

There was a task with the following content. A telephone number is organized (mobile or SIP - it does not matter, but multi-channel is better) to receive incoming calls. When receiving an incoming call, do the following:
1. Determine the number of the caller;
2. Transfer via the Internet via http(s) (POST or SOAP) the subscriber's number to a third-party service; in response to receive a certain digital combination or an error message;
3. Dictate the received digital combination to the caller by voice or play a pre-recorded error message (depending on what the third-party service returns).
Of course, the simplest option is an operator or a group of operators with the appropriate software. But I would like to make an automated solution. But I don’t really understand why you can start dancing. As a result, the following questions arose:
1. Are there ready-made third-party services or autoresponder programs that can be given such a task (maybe not for free, as long as it works well)?
2. Are there models of SIP or mobile phones or voice gateways that allow you to organize such an answering machine (for example, through your API)?
3. Is it possible to somehow organize something similar using Asterisk? What manuals do you need to study for this? If you need to add some scripts, in what languages ​​can this be done?

Answer 1

plivo.com
They have an open source fork that can be downloaded and deployed, essentially a freeswitch add-on. I won’t say the link because I have to look for it, because I’m too lazy :)
It will solve all your problems