Send outbound calls from LiveKit

Create a SWML Script

To create a SWML script, navigate to the Resources tab in your SignalWire Dashboard, click + Add New, and select SWML Script.

• Log in to your SignalWire Dashboard and navigate to the Resources tab on the left-hand sidebar.
• Click Add, select Script, and then choose SWML Script.
• Paste the following SWML code snippet into the editor:

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version: 1.0.0
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sections:
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  main:
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    - connect:
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        answer_on_bridge: true
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        from: "+1XXXXXXXXXX"
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        to: "%{call.to.replace(/^sip:/i, '').replace(/@.*/, '')}"

Be sure to replace "+1XXXXXXXXXX" with a phone number from your SignalWire account.

Add SIP address

• Save the SWML script and navigate to the Addresses & Phone Numbers section within the script.
• Click Add and select SIP Address to add your SIP domain application.
• Configure this SIP address based on your requirements, and save it.
• After configuration, note down your unique SIP domain.

Example SIP domain: test-space-live-kit.dapp.signalwire.com.

Create an outbound trunk

Use the following JSON configuration for creating an outbound SIP trunk, ensuring you update the given fields:

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{
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   "trunk": {
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      "name": "My Outbound SIP Trunk",
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      "address": "test-space-livekit.dapp.signalwire.com",
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      "numbers": ["+15105550100"],
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      "auth_username": "<username>",
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      "auth_password": "<password>",
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      "transport": 3
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   }
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}

Update placeholders in the above JSON with the following:

Submit this request and save the generated Trunk ID. If you forget to save the Trunk ID, use LiveKit’s CLI tool to retrieve the trunk configurations.

Create SIP participant

To initiate outbound calls through your configured trunk, you’ll need to create a SIP participant in LiveKit. This process establishes the connection and manages the call flow. For detailed instructions on creating SIP participants and handling outbound calls, refer to LiveKit’s comprehensive guide to Creating a SIP Participant.

If you’re working with LiveKit AI agents for outbound calls, please see the LiveKit AI Agent Telephony Guide.

Final checks

• Ensure the trunk address matches exactly with the one created previously.
• Phone numbers must be in E.164 format (e.g., “+15105550100”) to ensure proper routing and connectivity.

Create a second script

In your new script, paste the following SWML:

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version: 1.0.0
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sections:
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  main:
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  - record_call:
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      format: mp3

Update the outbound SWML script

Then, modify your existing outbound SWML script by adding the confirm parameter under the connect method, and setting its value to the URL for the new recording script.

The result should look like this:

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version: 1.0.0
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sections:
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  main:
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    - connect:
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        answer_on_bridge: true
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        confirm: "your-recording-script-url"
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        from: "+1XXXXXXXXXX"
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        to: "%{call.to.replace(/^sip:/i, '').replace(/@.*/, '')}"