​ To learn more, see the sources I considered: [[1] Webhook Overview](https://docs.retellai.com/features/webhook-overview) [[2] Send & receive SMS](https://docs.retellai.com/deploy/enable-sms) [[3] Unlock AI Texting, SMS, & Chatbots with Retell AI Agents | Retell AI | Retell AI](https://www.retellai.com/blog/unlock-ai-texting-with-retell-ai-voice-agents) [[4] Node KB, Role-Based Access, Outbound SMS API & More](https://www.retellai.com/changelog/node-kb-role-based-access-outbound-sms-api-more) ​

### Answer --- Yes, you can send an SMS message to a third party when an event like a transfer is triggered. There are a couple of approaches: 1. Using Webhooks You can use the

call_ended

webhook to trigger SMS sending when a call completes (including after a transfer) . The webhook will POST event data to your endpoint, which you can then use to trigger your SMS logic. [(1) ]() 2. Using SMS Nodes in Conversation Flow If you're using Conversation Flow, you can add a Send SMS node that triggers during the call flow—for example, right before or after a transfer action. This allows you to send texts during calls without extra setup. [(2) ]() [(3) ]() 3. Using Outbound SMS API You can programmatically send SMS using the [Create Outbound SMS API]() to send messages to any number. [(4) ]() Important Requirements: - SMS capabilities must be enabled on your phone number (requires business profile, brand, and SMS campaign approval for Retell Twilio numbers) . [(2) ]() - Current SMS capabilities are limited to US numbers only. - If using your own Twilio number, it must already have SMS capabilities enabled. For custom telephony numbers (non-Retell Twilio) , you may need to use a custom function to send SMS through your own Twilio integration. [(9) ]()

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.

### Answer The available documentation for Telnyx integration with Retell AI focuses on voice call setup via Elastic SIP Trunking—it does not explicitly cover SMS functionality through Telnyx. [(1) ]() For SMS capabilities in Retell AI, the documented approach requires either: 1. Retell Twilio numbers with SMS enabled (requires business profile, brand, and SMS campaign approval) [(2) ]() 2. Your own Twilio number with SMS capabilities already enabled, integrated via Twilio credentials The Telnyx setup guide covers voice configuration only: creating the SIP trunk, adding Retell's FQDN (

sip.retellai.com

) , setting up authentication, and configuring inbound/outbound voice settings. [(1) ]() If you need SMS through Telnyx, you would likely need to implement a custom function that interacts directly with Telnyx's SMS API outside of Retell's built-in SMS features. This is similar to how custom telephony users handle transfers—by writing custom logic that interfaces with their telephony provider. [(3) ]() Check out these potentially useful sources: - [Telnyx]() - [Send & receive SMS]() - [Custom Telephony Overview]() Would you like a general answer on how to approach building a custom function for Telnyx SMS?

​ To learn more, see the sources I considered: [[1] Telnyx](https://docs.retellai.com/deploy/telnyx) [[2] Send & receive SMS](https://docs.retellai.com/deploy/enable-sms) [[3] Custom Telephony Overview](https://docs.retellai.com/deploy/custom-telephony) ​

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.