A2P Registration
A2P (Application-to-Person) registration is the mandatory compliance process for sending SMS and MMS messages through mobile carriers in the United States. Specifically, this involves 10DLC (10-Digit Long Code) registration, where your client’s business is registered with The Campaign Registry (TCR) and approved by carriers like T-Mobile, AT&T, and Verizon. Without this registration, messages will be filtered, throttled, or blocked entirely.
Why This Matters
If you skip A2P registration or delay it, your client’s SMS messages will not get delivered. It is that simple. Since late 2023, carriers have aggressively enforced 10DLC compliance. Unregistered numbers see delivery rates drop below 10 percent. Messages get silently filtered, meaning they appear “sent” in your system but never reach the recipient’s phone.
For agencies building systems around missed-call text-back, review requests, appointment reminders, or any SMS-based automation, A2P registration is not optional. It is the foundation that makes messaging work. Every day without registration is a day your client’s automations are firing into the void.
The registration process also takes time. Carrier review can take anywhere from a few days to several weeks, depending on the business type and the accuracy of the submitted information. Starting this process immediately after the Agreement Signature is critical because delays here cascade into delays across the entire onboarding timeline.
How to Think About It
Think of A2P registration as getting a license to send messages. Just like a business needs a license to operate, it needs carrier approval to send SMS at scale. The registration process verifies that the business is legitimate, the messaging use case is compliant, and the content meets carrier standards.
The registration has three layers. First, the brand registration, where the business identity is submitted to TCR. This requires the EIN Verification and Legal Business Name to match carrier records exactly. Second, the campaign registration, where you describe how the business will use SMS (appointment reminders, marketing, review requests, etc.). Third, carrier vetting, where T-Mobile and other carriers review and approve the campaign.
Accuracy matters more than speed at this stage. A registration submitted with incorrect information will be rejected, and resubmission adds weeks to the timeline. Get the details right the first time. That means using the exact business name from the EIN letter, the correct address, and accurate phone numbers. Close enough is not good enough here.
Common Mistakes
Using a DBA instead of the legal business name. Carriers match against legal records, not the name on the storefront. “Joe’s Plumbing” might be the brand name, but if the EIN letter says “Joseph Smith LLC,” that is what goes on the registration. See Legal Business Name for more on this.
Submitting before EIN verification is complete. Rushing the registration with unverified information leads to rejections. Wait until you have the confirmed EIN details before submitting. The few extra days of verification time save weeks of resubmission time.
Choosing the wrong campaign use case. If the client plans to send marketing messages but you register as “appointment reminders only,” carriers may reject the registration when the actual message content does not match. Be accurate and comprehensive about the messaging use cases.
Not informing the client about the timeline. A2P approval is not instant. Clients who expect to send SMS on day one will be frustrated when they learn there is a waiting period. Set expectations during onboarding: “Your SMS capabilities will be active once carriers approve your registration, typically within one to three weeks.”
Treating it as a one-time setup. Compliance requirements evolve. Carrier rules change. Campaign registrations may need updates if the client’s messaging use cases change. Build periodic compliance reviews into your service delivery.
Tools Involved
A2P registration is managed through your SMS provider’s compliance portal. If you are using GHL’s phone system, the registration process is handled within the GHL platform through their Twilio or LC Phone integration. The information needed comes from EIN Verification and Legal Business Name confirmation. Tracking registration status can be monitored through GHL or directly through TCR.
Where This Fits
A2P registration begins immediately after the Agreement Signature and runs in parallel with EIN Verification. It depends on accurate business information from the EIN verification process. The final step in this compliance chain is Carrier Approval, where carriers review and approve the submitted registration. Until carrier approval is granted, SMS-dependent automations should not be activated.
Common Questions
How long does A2P registration take? Brand registration through TCR is usually approved within a few days. Campaign registration and carrier vetting can take one to three weeks. In some cases, especially for businesses in regulated industries, it can take longer. Plan for two to three weeks total and be pleasantly surprised if it is faster.
What happens if the registration is rejected? You will receive a rejection reason from TCR or the carrier. Common reasons include mismatched business information, vague campaign descriptions, or incomplete submissions. Fix the identified issues and resubmit. Each resubmission goes through the review process again, so getting it right the first time is far more efficient.
Can the client send any SMS while waiting for approval? Technically, messages can be sent from an unregistered number, but delivery rates will be extremely low. It is better to wait for approval than to send messages that never arrive. Use the waiting period to build and test automations so everything is ready to activate the moment approval comes through.