Making outbound calls

Workflow for making outbound calls.

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Outbound call workflowSetup for making callsSIP trunking provider setupLiveKit SIP configurationMake an outbound callNext steps

Outbound call workflow

To make an outbound call, you create a SIP participant with the user's phone number. When you execute the CreateSIPParticipant request, LiveKit SIP sends an INVITE request to your SIP provider. If the SIP provider accepts the call, the SIP participant is added to the LiveKit room.

LiveKit outbound SIP workflow
  1. Call the CreateSIPParticipant API to create a SIP participant.
  2. LiveKit SIP sends an INVITE request to the SIP trunking provider.
  3. SIP trunking provider validates trunk credentials and accepts the call.
  4. LiveKit server places SIP participant in the LiveKit room specified in the CreateSIPParticipant request.

Setup for making calls

The following sections outline the steps required to make an outbound SIP call.

SIP trunking provider setup

  1. Purchase a phone number from a SIP Provider.

    For a list of tested providers, see the table in Using LiveKit SIP.

  2. Configure the SIP Trunk on the provider to send SIP traffic to accept SIP traffic from the LiveKit SIP service.

    For instructions for setting up a SIP trunk using Twilio or Telnyx, see Configuring a SIP provider trunk.

LiveKit SIP configuration

Create an outbound trunk associated with your SIP provider phone number. This is the number that is used to dial out to the user. Include the authentication credentials required by your SIP trunking provider to make calls.

Make an outbound call

Create a SIP participant. When the CreateSIPParticipant request is executed, a SIP call is initiated:

  1. An INVITE request is sent to the SIP trunk provider. The provider checks authentication credentials and returns a response to LiveKit.

  2. If the call is accepted, LiveKit dials the user and creates a SIP participant in the LiveKit room.

    If the call is not accepted by the SIP trunk provider, the CreateSIPParticipant request fails.

After the call starts ringing, you can check the call status by listening to participant events:

  • If the sip.callStatus participant attribute is updated to active, the call has connected.
  • If the call fails, the participant is disconnected and leaves the room.

Next steps

Use the quickstart guide to create an agent that makes outgoing calls.

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