Does Twilio provide any APIs or services that can detect if call has been placed on hold by the receiver?

Question

I'm placing a call from my React Native application using Twilio and the outbound call works fine. Now I want to create something that will detect when I am put on hold by the receiver. The idea here is to make my app hold for me and get back to the caller once the hold has ended. I searched the twilio docs and services but could not find any thing regarding this use case. How would I go about doing this?

Answer 1

Twilio developer evangelist here.

Unfortunately, there is no mechanism to make this happen, even if there were something in the SIP signaling from the carrier, such as a re-INVITE.

In the world of SIP, putting a call on hold often involves sending a re-INVITE with different media parameters, such as saying a=sendonly in the session description. Even if this were passed end-to-end through the PSTN to Twilio, we do not generate webhooks to inform the customer’s app of this fact.

There are some good SO questions about placing a Twilio call on hold and retrieving it later--the Enqueue verb might be helpful.