Is there an API that I can use to stop recording an ongoing call?
We have a feature here where you can record only pieces of a call. So you can click a button to stop recording, and then after some time you can click another button to start recording again.
How can I accomplish that on Twilio? I didn't find anything in their docs.
Twilio developer evangelist here.
There's no direct way to start and stop recording a call, however you could manage this using <Gather> and <Conference>.
The idea would be that callers would join a conference (even if there's just two of them) which recorded their call using the record attribute.
You would wrap that <Conference> in a <Gather> that was waiting for a caller to dial a particular digit which stops recording by redirecting the caller who pressed the digit to a new <Conference> without the record attribute set.
You will also need to redirect the other call to that conference too. When you get the webhook after the first caller pressed a digit to stop recording you can fire off a REST API call to redirect the second caller to the new non-recorded conference.
If you wrap this second <Conference> in a <Gather> too, you can reverse this process to start recording again.
Let me know if that helps at all.
[edit]
As a further consideration, I realised that you indicated you need a user to press a button to start or stop recording. I initially thought of this as a button on your phone, which is why I suggested using <Gather>. If, however, the user in control of recording is an agent in a call centre, for example, you could build an easier interface using Twilio Client to make or receive the calls.
Then, when the calls are connected into the initial conference you'd need to record both the Call SIDs.
You could then implement a button in your interface that when pressed transfers both calls from a recording conference to a non recording conference (or vice versa). Again, this would use the REST API to redirect the calls.