### Answer To enable SMS capabilities for Retell Twilio numbers, you need to complete an A2P (Application-to-Person) application and approval process. [(1) ]() The process involves these steps: 1. Get approved for a business profile (free) 2. Get approved for a brand based on the business profile ($4 one-time fee for low-volume or $45 for standard) 3. Get approved for an SMS campaign ($15 one-time fee) The entire application can take around 2-3 weeks, sometimes longer, as it requires manual review by the telephony provider. You'll be notified via email when the application is approved or rejected. Once SMS is enabled, you can bind SMS agents to your phone number using the

inbound_sms_agents

and

outbound_sms_agents

fields when creating or updating a phone number. [(2) ]() [(3) ]() For example, when importing a phone number:

javascript
import Retell from 'retell-sdk';
const client = new Retell({
 apiKey: 'YOUR_RETELL_API_KEY',
}) ;
const phoneNumberResponse = await client.phoneNumber.import({
 phone_number: '+14157774444',
 termination_uri: 'someuri.pstn.twilio.com',
}) ;

[(2) ]() The response will include

inbound_sms_agents

and

outbound_sms_agents

arrays where you can configure agents with weights for SMS handling. [(2) ]() [(4) ]() [(3) ]() Note: SMS capabilities are currently limited to US numbers only. [(1) ]()

​ To learn more, see the sources I considered: [[1] Send & receive SMS](https://docs.retellai.com/deploy/enable-sms) [[2] Import Phone Number](https://docs.retellai.com/api-references/import-phone-number) [[3] Create Phone Number](https://docs.retellai.com/api-references/create-phone-number) [[4] Get Phone Number](https://docs.retellai.com/api-references/get-phone-number) ​

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