Enable native Twilio inbound calling (only SIP visible)

Support Help
1

Hi Retell team,

I’m building an AI receptionist and need native Twilio inbound calling enabled.
In my workspace, under Deploy → Phone Numbers, I only see SIP trunking and no option
to connect a Twilio number or get an inbound webhook.

Could you please enable native Twilio telephony / inbound voice webhooks for my account?

Thanks!

2

Retell AI integrates with Twilio via Elastic SIP Trunking, which is the recommended method(1). This approach connects your Twilio numbers to Retell AI’s VoIP infrastructure through SIP, enabling both inbound and outbound calls(1)(2).

To connect your Twilio number:

  1. Create an Elastic SIP Trunk in Twilio(3)

    • Set up termination (for outbound calls) with your termination SIP URI(3)
    • Configure origination (for inbound calls) using Retell’s SIP server: sip:sip.retellai.com(3)
    • Whitelist Retell’s IP addresses: 18.98.16.120/30 (all regions), 143.223.88.0/21 (certain US traffic), and 161.115.160.0/19 (certain US traffic)(1)

  2. Move your Twilio number to the SIP trunk(3)

  3. Import the number into Retell AI(3)

    • Provide your termination SIP URI from step 1(3)
    • Include authentication credentials if you set them up(3)
    • You can import via the dashboard or programmatically using the Import Number API(3)

Once imported, your number will appear in your Retell dashboard and function like any Retell-purchased number(3). You can assign agents to handle inbound calls and make outbound calls directly(3).

The SIP trunking method you’re seeing in your workspace is the correct integration path for Twilio(1)(3).