Businesses that send SMS or MMS messages to U.S. recipients using standard 10-digit phone numbers must register those numbers for A2P 10DLC messaging. Registration helps carriers verify legitimate business traffic, reduce filtering, and prevent message disruptions. Unregistered 10DLC traffic to U.S. recipients may be blocked.

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What Is A2P 10DLC?

A2P 10DLC is the U.S. carrier registration framework for Application-to-Person messaging sent through standard 10-digit long code phone numbers. Registration connects your business, messaging use case, and phone numbers so carriers can identify approved business messaging traffic.

A2P 10DLC generally applies to business SMS and MMS messages sent to U.S. recipients using local 10-digit numbers.


Key Benefits of A2P 10DLC Registration

Registration helps protect the reliability of your business messaging and ensures your phone numbers are associated with an approved messaging use case.

  • Reduced message blocking: Registered traffic is less likely to be rejected for being unidentified.

  • Carrier compliance: Helps meet U.S. carrier requirements for business messaging.

  • Improved message trust: Carriers can identify the business and approved messaging purpose.

  • More reliable delivery: Proper registration reduces disruptions caused by unregistered traffic.

  • Clear campaign ownership: Your business, campaign, and phone numbers are connected under the approved registration.


What You Need to Know

Carrier requirements apply to business messages sent to U.S. recipients through 10-digit long code numbers. Understanding these requirements before sending can help prevent avoidable delivery failures.

Important considerations include:

  • SMS and MMS sent through 10DLC numbers should be associated with an approved A2P campaign.

  • New registrations require business information, campaign details, message samples, and proof of recipient consent.

  • Campaign registration and approval may take time.

  • Unregistered or improperly associated numbers may experience blocking.

  • Blocked unregistered 10DLC traffic may return an error such as 30034.

  • Messaging charges may still apply when a delivery attempt is made, depending on the applicable billing rules.


Why A2P Registration Is Required

U.S. carriers use A2P 10DLC registration to identify legitimate business senders and reduce unwanted messaging. Registration creates a verified connection between the business sending messages and the type of communication recipients should expect.

The process is designed to help carriers:

  • Identify who is sending messages.

  • Understand the intended messaging use case.

  • Confirm that recipients have an appropriate opt-in path.

  • Reduce spam and unwanted messaging.

  • Apply carrier messaging requirements consistently.

Registration does not guarantee delivery. Message content, recipient consent, opt-out rates, carrier filtering, and sending behavior can still affect message delivery.

What Must Be Registered?

A complete A2P setup typically includes multiple components. Each component must be approved and connected correctly before relying on the number for U.S. business messaging.

Brand Registration

Brand registration identifies the business responsible for sending messages.

Business details should match official registration records, including the legal business name, business registration information, address, and other required information.


Campaign Registration

A campaign describes how the business plans to use SMS or MMS.

Campaign information may include:

  • Messaging purpose

  • Expected message content

  • Sample messages

  • How recipients opt in

  • How recipients can opt out

  • The type of messages recipients will receive

The campaign description should accurately represent the messages you actually intend to send.

Phone Number Assignment

After the campaign is approved, the applicable 10DLC phone numbers must be associated with the approved campaign.

A phone number that has been purchased but is not connected to the appropriate approved campaign may still experience messaging failures.


How to Prepare for A2P 10DLC Registration

Preparing accurate information before starting registration can reduce delays and prevent avoidable rejections.

Before submitting:

  1. Confirm your legal business information.

  2. Identify the messaging use case.

  3. Document how recipients provide SMS consent.

  4. Prepare representative message samples.

  5. Include clear sender identification where required.

  6. Include appropriate opt-out instructions.

  7. Confirm your website and opt-in pages accurately represent your messaging program.

  8. Review your messages for prohibited or restricted content.


How to Complete A2P 10DLC Registration

Proper registration requires both an approved business identity and an approved messaging campaign.

  1. Open Settings.

  2. Navigate to Phone Numbers.

  3. Open the messaging registration or trust settings.

  4. Begin the A2P registration process.

  5. Enter the required business information.

  6. Submit the business or Brand registration.

  7. Wait for the Brand registration to be approved.

  8. Complete the Campaign registration.

  9. Provide the campaign use case, sample messages, and opt-in information.

  10. Submit the Campaign for review.

  11. After approval, confirm the applicable phone numbers are associated with the approved campaign.

  12. Allow additional time for carrier systems to recognize the approved registration.

Important: Avoid repeatedly resubmitting a rejected registration without correcting the reason for rejection. Incorrect or inconsistent business information can cause additional delays.


If You Are Already Registered

Businesses that already have approved A2P campaigns generally do not need to create another registration solely because of these requirements.

Confirm that:

  • Your Brand is approved.

  • Your Campaign is approved.

  • The campaign accurately reflects your current messaging use case.

  • All applicable phone numbers are associated with the approved campaign.

  • Your messaging continues to follow the consent and content requirements submitted during registration.

If you purchase additional 10DLC numbers, verify that the new numbers are connected to the appropriate approved campaign before using them for messaging.

Using Toll-Free Numbers as an Alternative

Toll-Free numbers use a separate verification process and are not registered through A2P 10DLC.

A Toll-Free number may be appropriate when you prefer that type of business number or when it better matches your messaging strategy. Toll-Free numbers must still complete their applicable messaging verification requirements before being relied on for SMS or MMS.

Switching to a Toll-Free number does not remove the need to follow messaging consent, opt-out, content, and carrier requirements.


What Happens If a Number Is Not Registered?

Unregistered 10DLC traffic to U.S. recipients may be blocked by carriers. A blocked message may display an error indicating that the number is not associated with an approved A2P campaign.

If messages fail:

  • Confirm the number is a 10-digit long code number.

  • Check the Brand and Campaign approval status.

  • Confirm the number is associated with the correct campaign.

  • Allow time for carrier systems to update after approval.

  • Review the displayed error code before attempting additional sends.


Best Practices for Reliable A2P Messaging

Registration is only one part of maintaining successful business messaging. Ongoing sending practices can also affect deliverability.

  • Send messages only to recipients who have provided appropriate consent.

  • Clearly identify your business in initial messages.

  • Provide a simple way to opt out.

  • Honor opt-out requests immediately.

  • Keep campaign details consistent with the messages you actually send.

  • Avoid purchased or shared contact lists.

  • Monitor delivery errors and opt-out rates.

  • Avoid prohibited or misleading content.

  • Keep business and campaign information current.


Frequently Asked Questions

Q: Does A2P 10DLC apply to every phone number?

No. It applies to business messaging sent to U.S. recipients through standard 10-digit long code phone numbers. Toll-Free and short code numbers follow separate requirements.

Q: Does A2P 10DLC apply to MMS as well as SMS?

Yes. Business SMS and MMS sent through applicable 10DLC numbers are subject to A2P registration requirements.

Q: What happens if I send from an unregistered 10DLC number?

The message may be filtered or blocked by the receiving carrier.

Q: What does error 30034 mean?

This error can indicate that U.S.-bound messaging is being sent from a 10DLC number that is not properly registered or associated with an approved campaign.

Q: Do I need to register again when I purchase a new number?

You may not need a new Brand or Campaign registration, but the new number must be associated with the appropriate approved campaign before it is used for A2P messaging.

Q: Does registration guarantee message delivery?

No. Registration reduces issues associated with unidentified traffic, but carriers can still filter messages based on content, consent, sending behavior, recipient complaints, and other factors.

Q: Can I use a Toll-Free number instead?

Yes. Toll-Free messaging follows a separate verification process and may be used instead of a local 10DLC number when appropriate.


Need Help?

If your A2P 10DLC messages are being blocked or your registration is not working as expected, first review the Brand, Campaign, and phone number association.

Verify that:

  • The Brand registration is approved.

  • The Campaign registration is approved.

  • The messaging use case matches the approved campaign.

  • The affected 10DLC number is associated with the approved campaign.

  • The number was not added after registration without being properly connected.

  • Your opt-in method and message content follow the approved use case.

  • Recipients have provided appropriate consent.

  • Enough time has passed for carrier systems to recognize a recently approved registration.

  • Any error code, including 30034, has been reviewed before resending.

If the issue continues, collect the affected phone number, Brand status, Campaign status, message example, opt-in method, error code, and screenshots of the registration status before contacting support.