FAQs about US carrier registration

In order to use US phone numbers to send texts for your business, you will need to be registered and approved as a US carrier to do so.

To decrease the amount of spam texts and calls received by their customers, all major US cell phone carriers require businesses to comply with a new standard. This standard, known as A2P 10DLC, ensures that SMS and MMS messages and voice calls to US numbers are sent by verified virtual phone numbers.

All virtual phone number owners, including OpenPhone subscribers, must register. The questions and answers here will help you understand the process and successfully register. Also, fully review our US carrier registration guide for more information on how to get registered.

Basics About Registration Pre-registration Post-registration FAQs


What is A2P 10DLC? A2P 10DLC refers to a standard in the United States that allows businesses to send Application-to-Person (A2P) type messaging via standard 10-digit long code(10DLC) phone numbers. Major US carriers consider all messages sent using virtual phone numbers with local area codes, like the ones provided by OpenPhone, to be A2P.


  • Brand - The identifier for your organization or who you are
  • Campaign - The type of text messages you’re sending across carrier networks

Who is required to register as US carrier? Every OpenPhone customer, as virtual phone users who send texts to any US number needs to register, whether using OpenPhone for business or personal use (i.e., texting friends and family). We are not able to support a personal use case exemption at this time.

If I'm not eligible to register, what can I do? We recommend getting then switching to a toll-free number, which isn’t currently bound by these new regulations.

What is STIR/SHAKEN? STIR/SHAKEN (also referred to as SHAKEN/STIR ) is a protocol mandated by the FCC.  It's a caller authentication framework developed by ATIS and IETF that helps reduce fraudulent robocalls. With STIR/SHAKEN protocols, carriers may flag non-compliant callers on the recipient’s caller ID as:

  • Possible spam
  • Suspected robocall
  • Scam likely

How long does registration take? The time for completing the entire registration process can vary. We have received some approvals as quickly as 5-7 business days; others have remained in pending status for up to 30 days. In rare cases where key information is unable to be verified expediently, registration may take longer than 30 days. Reminder - You are not able to message US numbers while awaiting registration approval.

If my registration is rejected, what can I do?

A third-party company handles the verification of your information, and we do not have any control over whether your application is approved or rejected. The information we receive is limited. However, you can view the reason your application was rejected in-app and in a related email. You should reference this information to resubmit your application for approval.

Important: Your text messages will only be successfully delivered if you have a successful registration.