Business SMS Compliance: What Is A2P 10DLC and What Do You Need to Do?

If your business sends text messages to customers — appointment reminders, order confirmations, follow-ups, promotional messages — there's a compliance framework you need to know about: A2P 10DLC. It's not optional, it's not going away, and businesses that haven't registered are already seeing their messages filtered or blocked by the major carriers.

The good news: for most small businesses, the registration process is straightforward and one-time. Here's everything you need to know.

What Does A2P 10DLC Mean?

A2P stands for "Application-to-Person" — meaning messages sent from a business system (an application) to an individual customer's phone. 10DLC stands for "10-Digit Long Code" — your standard 10-digit local business phone number (as opposed to a short code like 12345 or a toll-free number).

Together, A2P 10DLC is the U.S. carrier-mandated framework for registering and vetting business phone numbers that send text messages. It was introduced by AT&T, Verizon, and T-Mobile (through The Campaign Registry) to combat spam and improve SMS deliverability for legitimate businesses.

Who Needs to Register?

Any business that sends SMS or MMS messages from a 10-digit local business phone number needs A2P 10DLC registration. This includes:

• Appointment reminders (dental offices, salons, medical practices)
• Order and delivery notifications (retail, e-commerce, restaurants)
• Customer follow-up messages ("How was your experience?")
• Missed call auto-replies
• Promotional or marketing text blasts
• Two-way customer service conversations initiated by the business

If you're a solo operator texting from your personal cell phone to individual customers manually, A2P 10DLC does not apply. It applies to business phone systems that send messages programmatically or at scale.

Unregistered business numbers sending A2P messages are subject to carrier filtering — meaning your texts may be silently blocked before they reach the customer's phone.

What Happens if You Don't Register?

Carriers (AT&T, Verizon, T-Mobile) actively filter SMS traffic from unregistered numbers. The consequences range from reduced message deliverability to complete message blocking. You won't always know it's happening — your system shows the message as "sent," but the customer never receives it.

As carrier enforcement has tightened through 2024 and 2025, businesses relying on SMS for appointment reminders or customer follow-ups have seen significant drops in response rates — often without realizing their messages weren't being delivered.

What Information Do You Need to Register?

Registration happens at two levels: your Brand (who you are as a business) and your Campaign (what types of messages you send). Here's what's required:

Brand Registration

• Legal business name (must match government records)
• EIN (Employer Identification Number) — or SSN for sole proprietors
• Business type (LLC, Corporation, Sole Proprietor, etc.)
• Physical business address
• Business website
• Contact email and phone

Campaign Registration

• Use case type (appointment reminders, customer care, marketing, mixed, etc.)
• Sample messages — 2–3 examples of the actual texts you send
• Opt-in method — how customers consent to receive your texts
• Opt-out language — confirmation that your messages include STOP instructions

What Is the Opt-In Requirement?

You must have documented consent from customers before sending them business text messages. This consent can be collected via a web form with an SMS opt-in checkbox, verbally at the point of service (with a log), a signed paper form, or a double opt-in text (customer texts a keyword to opt in). You cannot send business SMS to numbers that haven't opted in — this is both an A2P requirement and a TCPA legal obligation.

What Are the Fees?

The Campaign Registry charges a one-time brand registration fee ($4) and a monthly campaign fee ($10/month per use case). These fees are typically passed through by your VoIP provider. Some providers bundle them into the plan; others bill them separately. Either way, the cost is minimal relative to the business risk of undelivered messages.

How Long Does Registration Take?

Brand registration is usually approved within 24–48 hours for standard businesses with a valid EIN. Campaign registration can take 2–5 business days. Sole proprietors and businesses without an EIN go through a slower vetting process and may take 2–3 weeks.

What About Toll-Free Numbers and Short Codes?

Toll-free numbers (800, 888, 877, etc.) have a separate registration process called Toll-Free Verification, not A2P 10DLC. Short codes (5–6 digit numbers) have their own dedicated short code approval process. A2P 10DLC applies specifically to standard 10-digit local numbers used for business texting.