Question

When I use the Twilio Programmable Voice Conference Participant API to add a call to a conference, is the participant added immediately, or only after they answer the call? 

Product

Programmable Voice  

Environment

Conference Participant API

Answer

When you add a participant to a Twilio conference using the Conference Participant API, Twilio initiates an outbound call to the participant. The participant is only added to the conference after they answer the call. If the participant does not answer, they are never joined to the conference. This ensures that other conference participants do not hear ringing or early media from the outbound call.

Additional Information 

• This behavior applies to standard PSTN and client calls.
• For more details, see the Twilio Conference Participant API documentation