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Voice Conference


Learn about Twilio Voice Conference, a flexible solution that allows developers to manage multi-party audio calls ranging from 2 to 250 participants. You can use this guide to build inbound contact centers, create outbound contact centers, and set up call tracking.

See Related reference documentation to learn more about the TwiML nouns and API resources used in this guide.

A participant can dial into a Conference via PSTN, SIP or via Twilio Voice Client. The developer can manage the participant experience programmatically and participants can be waiting for the Conference to start, muted, placed on hold or removed from the Conference. In addition, there is coaching functionality so that a "coach" participant can talk to one participant without the other participant hearing the audio.


Lifecycle of a Conference

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There are two ways to create a Conference:

  1. Using the <Conference> TwiML noun to handle an incoming call.
  2. By adding a participant to a named Conference using the Create Participant API.

The Conference is created when the first participant connects to the Conference. At that time the participant is in a waiting state and will hear hold music. If the Conference is configured with a moderator, then the Conference will not start until the moderator joins and all participants will hear hold music until then. If there is no moderator, the Conference starts when the second participant joins. Once the Conference starts, participants will be able to hear each other. If configured, the Conference will be recorded for later playback.

During the active Conference participants can be placed on hold or muted. Additional participants can join or leave. Announcements can be played to participants and if needed a participant can be removed programmatically.

There are three ways that a Conference can end:

  1. The Conference status is set to "Completed" via the Update Conference API
  2. All participants have left the Conference
  3. The moderator leaves the Conference or is disconnected

Managing Conferences & Participants

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There are two resources available to developers to manage Conferences and participants:

These resources have attributes that can be fetched or modified via REST APIs. In addition, developers can setup a Conference webhook to receive status events related to Conferences and participants.


  • Announcements (Beep & Music) - a Conference can be configured to beep when a new participant joins. In addition, a developer defined announcement can be played to a participant at any time after the Conference has started
  • Managing Participants (Hold, Mute & Remove) - when a participant is placed on hold, they will hear developer-defined hold music and will not hear any other participants. If a participant is muted then no other participants will hear them but the participant will be able to hear the others. Finally a participant can always be removed from a Conference.
  • Conference Recording - it is possible to record a Conference and all the participants from when a Conference starts
  • Transfer (Warm & Cold) - a Conference can be used to manage a call transfer when there are two participants. In a warm transfer a new participant is added to the Conference and then the three participants can talk before the participant who initiated the transfer drops off. In a cold transfer, again a new participant is added to the Conference, however the participant who initiates the transfer drops off before the new participant answers.
  • Participant Coaching (Monitor & Whisper) - a participant can take the role of monitor or supervisor in a Conference. This participant can join the Conference muted and just listen in to the Conference. Another variation is when the participant joins the Conference as a coach and can "whisper" to one participant without the other participants hearing.

Use cases for Voice Conference with Twilio Programmable Voice

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This guide covers a feature that can support the following use cases:

Create an inbound contact center with Twilio Programmable Voice

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You can use the feature in this guide to connect incoming customer calls to multiple agents or support teams within an audio bridge. For example, you can route callers to specific departments, manage queues, and place participants on hold with custom music while waiting for an agent to join.

To learn more advanced features that you can use with inbound contact centers, see Voice inbound contact center.

Create an outbound contact center with Twilio Programmable Voice

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You can use the feature in this guide to build programmatic multi-party dialers that connect your agents to customers simultaneously. This enables efficient outbound campaigns, telemarketing workflows, and unified communication strategies.

To learn more advanced features that you can use with outbound contact centers, see Voice outbound contact center.

Set up call tracking with Twilio Programmable Voice

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You can use the feature in this guide to bridge calls between buyers, sellers, or agents while tracking key conversation metrics. By managing these multi-party connections, you can monitor call performance, evaluate marketing ROI, and gain visibility into how participants interact.

To learn more advanced features that you can use with call tracking, see Voice call tracking.


Explore the following guides to build on what you've learned in this guide: