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To send SMS from your own Retell number, you need an approved A2P 10DLC campaign. This page walks through each field of the campaign application, with templates and the rules reviewers apply, to help you write one that meets carrier requirements. Human reviewers read your use case, description, opt-in flow, and sample messages together, so keep the four consistent with each other. This page covers only the campaign form, which you reach after your business profile and brand are in place. The form also requires a card on file in Retell billing. For the full SMS setup, see Enable SMS.

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Form fields and limits

In the dashboard, open your phone number and go to Advanced Add-Ons > SMS > Campaign Registration > Add Campaign Application.
Add Campaign Application dialog over a dimmed phone number page, with empty fields for Application Name, Use Case, Description for the use of sms, two Sample Message boxes, How do end-users consent to receive messages, Privacy Policy URL, and Terms and Conditions URL, all marked required, and a disabled Save button

The Add Campaign Application form, with the business profile and brand steps completed behind it.

Two things Retell sets for you that affect how you write the samples:
  • Your campaign is submitted with “messages contain links” and “messages contain phone numbers” both set to yes. A link or phone number in a sample is fine and expected. Links must point to your own domain. Public URL shorteners such as bit.ly or tinyurl are rejected.
  • STOP, UNSUBSCRIBE, CANCEL, END, QUIT, and HELP replies are handled by Twilio’s default opt-out handling on Retell numbers. You don’t configure keywords, but every sample and your opt-in script must still tell people they can reply STOP.

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Fill out the application

1

Choose a use case

Pick the one that describes what you will actually send. If more than one applies, choose Mixed. If your volume is small, choose Low Volume Mixed, which covers any combination up to 2,000 message segments per day. Retell’s campaign fee is the same for every use case.
Rejected regardless of use case:
  • Debt collection of any kind, including payment reminders that read like collections.
  • Sex, hate, alcohol, firearms, and tobacco or cannabis content without age-gating.
  • High-risk financial content such as loans, payday lending, credit repair, debt relief, and cryptocurrency.
  • Lead generation, affiliate marketing, or messaging on behalf of a third party.
  • More than one brand in a campaign.
2

Write the campaign description

Reviewers must be able to read this and know who is sending, to whom, what kinds of messages, and how recipients consented. Aim for three to six sentences.
Template
Example for Customer Care:
Acme Home Services uses this campaign to send two-way customer support messages, follow-ups to phone conversations, requested quotes and service information to existing customers and prospective customers who contact us by phone or request a call on our website at https://www.acmehomeservices.com/contact. Recipients opt in verbally during a call with our automated AI phone assistant, or by submitting our website contact form. Messages are transactional and informational only, sent after a call or when a customer requests information. Every message identifies Acme Home Services and includes opt-out instructions (reply STOP).
Example for Low Volume Mixed appointment reminders:
Bright Smile Dental uses this campaign to send appointment confirmations, appointment reminders, reschedule notices and post-visit follow-ups to patients who have booked an appointment with our office. Patients opt in verbally when they book by phone with our automated scheduling assistant, or by checking the SMS consent box on our online booking form at https://www.brightsmiledental.com/book. Messages are informational only and are sent when an appointment is booked, 24 hours before the appointment, and after the visit. Every message identifies Bright Smile Dental and includes opt-out instructions (reply STOP).
Say “automated AI phone assistant” plainly. Reviewers accept it, and hiding it reads as evasive. Name the content types you will send and stay consistent with the use case, rather than listing every message you might ever send.
3

Describe how end users consent

This field must describe where a person encounters the chance to opt in, the exact action they take to consent, and every disclosure below. If consent is collected by voice, paste the exact script your agent speaks.Mandatory disclosures:
  1. Business name
  2. What kind of messages they’ll get
  3. “Message and data rates may apply”
  4. Frequency statement, such as “Message frequency varies” or “up to 4 msgs/month”
  5. How to opt out (reply STOP) and get help (reply HELP)
  6. Direct link to the opt-in page, or the full transcript of the verbal script
  7. The customer’s confirmation: their “Yes” or their checked box
  8. Links to your Privacy Policy and Terms, in addition to the URL fields
  9. For web forms: consent is optional, not a condition of purchase, and the box is unchecked by default
Pick the flow that matches how you collect consent. If you use both, paste both, numbered “1. WEBSITE FORM OPT-IN” and “2. VERBAL OPT-IN DURING CALL”, followed by one “POST-OPT-IN CONFIRMATION” paragraph with the confirmation text.Verbal opt-in during a call with your agent
Verbal opt-in flow
For outbound calls, replace the second sentence with: “[Business Name]‘s assistant calls customers who [booked an appointment / requested a callback] at the number they provided.”If a website form only requests a callback, submitting it does not opt the user in to SMS. Say so in the flow, then describe how the agent collects consent on the call using the script above.Web form with a consent checkbox
Web form opt-in flow
Reviewers open your form and check that the checkbox is unchecked by default and not required to submit, that transactional and marketing texts each have their own checkbox, that SMS consent is separate from email consent and from accepting the Terms, and that the business name on the page matches the brand. If there is no checkbox because you send transactional messages only, the phone field must be optional with the disclosure directly under it.
4

Add your Privacy Policy and Terms URLs

Both URLs must be live, on your domain, start with https://, and appear in both the URL fields and inside the consent text.Your Privacy Policy must state that mobile opt-in data is never shared. Paste this under the section about sharing data with third parties:
Privacy Policy clause
Your Terms of Service, or a dedicated “Mobile Messaging Terms” page, should state the business name, the kinds of messages, “message and data rates may apply”, the frequency, how to opt out (STOP) and get help (HELP), and a support contact.
The reviewer opens the privacy URL and looks for the clause on that page. A link to a tab or anchor inside a long corporate privacy page gets rejected with “unable to locate the privacy policy details inside this provided link”. Link to a page where the clause is visible without clicking tabs or expanding sections, or publish a short dedicated SMS privacy page.
5

Write two sample messages

Each sample must be 20 to 200 characters and must:
  • Name [Business Name] in the text.
  • Include an opt-out line such as “Reply STOP to opt out”.
  • Show templated values in square brackets: [Date], [Time], [Agent Name].
  • Use only links on your own domain.
  • Match the use case and description. No discount code under Customer Care.
  • Use one frequency phrasing, such as “Msg frequency varies”, across both samples and the consent text.
A good pairing is one opt-in confirmation plus one message that shows your real content. Recount after replacing the placeholders: a long business name can push a sample past the limit, and anything over 160 characters sends as two segments.
Opt-in confirmation (any use case)
Post-call summary (Customer Care, Mixed)
Appointment reminder (Mixed, Low Volume Mixed)
Technician ETA (Delivery Notification)
Promotional (Marketing, Mixed)
6

Save and submit

Click Save. Save stays disabled until every required field passes validation. Saving closes the dialog and fills in Campaign Registration with the new campaign. Back on the SMS panel, click Next to submit the SMS application for this number.Each submission costs $15, charged whether or not the campaign is approved (as of September 2026). Twilio’s review of the campaign usually takes three or four business days once the brand is approved. Retell emails you when the campaign is approved or rejected, with the reason.
Your application promises a specific script. Whenever an agent collects consent, it must say that script. Add this to that agent’s prompt, and paste in the exact script you submitted in step 3.
Agent prompt: SMS consent
Make the first text the confirmation message from step 5, and include the business name and “Reply STOP to opt out” in every SMS the agent sends. If your real traffic doesn’t match the samples you filed, the number can be suspended.

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If your campaign is rejected

Retell shows the rejection reason on the campaign in the dashboard and emails it to you. Click Edit on the rejected campaign, fix the fields the reason points at, click Save, then click Next on the SMS panel to resubmit. Only rejected campaigns can be edited. Each resubmission is charged the $15 fee; your business profile and brand approvals carry over.

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What does the rejection wording mean?

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FAQ

No. You can file the campaign as soon as the brand exists and isn’t rejected. Retell holds it as pending and forwards it to Twilio automatically once the brand is approved.
No. Only rejected campaigns can be edited. To change what an approved number sends, delete the SMS capability on the number and create a new campaign. Your business profile and brand are kept and reused.
If you only need to send a fixed message during calls, you can send from an SMS-approved Retell number with no application. The content is a preset template you can’t customize, and two-way SMS isn’t supported. See Option 3 on the SMS page.
No. Twilio’s default opt-out handling applies to Retell numbers, so STOP, UNSUBSCRIBE, CANCEL, END, QUIT, and HELP are handled for you. Your samples and opt-in script must still tell people they can reply STOP.
For Twilio’s own guidance, see the campaign approval requirements, the list of campaign and use case types, and the forbidden message categories.