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This guide walks you through setting up Twilio Elastic SIP Trunking to route calls to Butter AI.

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Prerequisites

  • A Twilio account.
  • A phone number in your Twilio account.
  • A Butter AI SIP Inbound Trunk created (see Import Phone Number).

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Step 1: Create a SIP Trunk in Twilio

  1. Log in to the Twilio Console.
  2. Navigate to Elastic SIP Trunking > Trunks.
  3. Click Create new SIP Trunk.
  4. Name it (e.g., “Butter AI Trunk”).
  5. Click Create.

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Step 2: Configure Origination (Outbound from Twilio)

This tells Twilio where to send the call when someone dials your number.
  1. Select your new trunk and go to Origination.
  2. Click Add new Origination URI.
  3. Enter the SIP Server Address provided by Butter AI (e.g., sip.your-region.livekit.cloud).
    • Note: You get this URI when you create a SIP Phone Number in Butter AI.
  4. Enabled: Yes.
  5. Click Save.

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Step 3: Assign a Number

  1. Go to Numbers within your SIP Trunk settings.
  2. Click Add a number.
  3. Select an existing phone number from your account or buy a new one.
  4. Click Add Selected.

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Step 4: Configure Termination (Optional)

If you plan to make outbound calls from Butter AI through this Twilio trunk:
  1. Go to Termination.
  2. Enter a unique Termination URI (e.g., butter-ai-yourname.pstn.twilio.com).
  3. Under IP Access Control Lists, add the IP addresses provided by Butter AI (contact support for these).
  4. Alternatively, use Credential Lists to create a username/password that Butter AI will use to authenticate.

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Step 5: Verify

Call the phone number you assigned in Step 3. If everything is configured correctly, Twilio will forward the SIP invite to Butter AI, which will answer and connect you to your agent.