Most businesses meet A2P 10DLC the same way: the texts stop arriving. Nothing in the dashboard changes, no error appears, the send log still says delivered — and the replies simply stop. By the time somebody works out that the carrier has been dropping the messages for two weeks, a month of follow-up has quietly gone nowhere.
This guide covers the whole registration, in the order you will actually do it: the two applications and what each one is really asking, the documents to gather first, how to pick a use case, the six failures that account for most rejections, and what changes operationally once you are through. It is written for the person filling in the form, not for a compliance department.
What A2P 10DLC is, and who has to register
A2P is application-to-person: any message your software sends rather than a human thumb-typing it. 10DLC is the 10-digit long code — an ordinary local phone number, the kind your business already has. Put together, A2P 10DLC is the framework US carriers use to identify which businesses are behind automated texts sent from normal phone numbers.
It exists because long codes were never designed for bulk sending. Carriers could not tell a dental practice confirming appointments apart from a scam operation cycling through numbers, so in 2021 they stopped guessing and required registration instead. Brands register their identity with The Campaign Registry, the central body operating the system on behalf of AT&T, T-Mobile, Verizon and the other US carriers.
You need to register if you send any automated SMS or MMS to US mobile numbers from a 10-digit number. That includes the things nobody thinks of as marketing:
- Appointment reminders and confirmations
- Missed-call text-backs
- Lead follow-up sequences and drip campaigns
- Review requests
- Two-factor codes and account alerts
- Internal notifications sent to staff mobiles
The rule follows the sending method, not the content. A one-line "Running late?" text fired by a workflow is A2P. The same text typed by a receptionist on a handset is not. Practically, any business using a CRM to text customers is sending A2P traffic and needs to be registered.
Two things sit outside this framework. Toll-free numbers use a separate verification process with its own form and its own reviewers. Short codes — the five and six digit numbers large retailers use — are a different product entirely, with a longer lead time and a much higher price. This guide is about 10DLC, which is what almost every small and mid-sized business is actually sending from.
What unregistered traffic actually costs you
The consequence people expect is a bill or a warning email. What actually happens is quieter and considerably worse: carriers filter the traffic. The message leaves your platform, gets accepted by the carrier, and is dropped before it reaches the handset. Your dashboard shows it as sent. No bounce, no error, no notification.
That silence is what makes this expensive. A blocked send announces itself and gets fixed the same day. Filtered traffic can run for weeks while somebody assumes the leads have simply gone cold, and every hour of that costs you the thing texting was supposed to protect — the minutes right after a lead comes in, when a reply still changes the outcome.
Beyond filtering, unregistered or misregistered sending can attract carrier violation fees, and a number that accumulates spam complaints can end up with a reputation problem that survives the paperwork being fixed. Registration is cheap. Rebuilding a burned number's deliverability is not.
The two registrations, in order
Almost every avoidable delay comes from not understanding that this is two applications with two different reviewers, not one form.
Step one: Brand registration — who you are
The Brand record is your legal business identity. You submit your registered legal name, tax ID (EIN, or SSN for a sole proprietor), business address, entity type, industry vertical, website, and a contact name, email and phone.
This is checked against third-party business records rather than read by a person. It usually resolves in minutes to a few hours. The critical detail: it is your legal name that is verified, not your trading name. If you are incorporated as "Brescia Holdings LLC" and everyone knows you as "Summit Dental", the Brand record needs Brescia Holdings LLC. The trading name goes elsewhere.
Step two: Campaign registration — what you send
The Campaign record describes the messaging programme itself, and this one is genuinely read by a reviewer. You provide a use case, a plain-English description of what you send and why, at least two sample messages, a description of how people opt in, and confirmation of how opt-out is handled.
Campaign review typically takes one to three business days. A rejection sends you back to the start of that queue, which is the real reason a sloppy first submission costs a week rather than an hour.
Once the campaign is approved, your phone numbers are associated with it. Until that association exists, the numbers are unregistered — approval alone does not route anything.
What to have ready before you open the form
Gather these first. Every one of them is a place submissions stall.
- Your exact legal entity name — as filed, punctuation and all. Take it from your EIN letter or state registration, not from your letterhead.
- Your EIN, matching that name in IRS records. Sole proprietors without an EIN use a different, lower-throughput registration path.
- Your registered business address — the one on the entity filing, not necessarily the address customers visit.
- A live website that describes the business the registration claims to be.
- A privacy policy on that website stating explicitly that phone numbers and SMS consent are not sold or shared with third parties for marketing.
- Your opt-in mechanism, visible and describable — the actual form, checkbox or keyword, with its exact wording.
- Two or three real sample messages, written as they will actually send.
The privacy policy requirement catches more businesses than any other item on the list, because it is the one nobody associates with texting. Carriers open your site and look for it. If it is missing, or if it does not address SMS specifically, the campaign is refused regardless of how good everything else is.
Choosing the right campaign use case
The use case sets what you may send and how fast. Pick it honestly — it is checked against your sample messages, and a mismatch is an instant rejection.
| Use case | Covers | Choose it when |
|---|---|---|
| Customer Care | Support replies, appointment confirmations, service updates | Everything you send is to an existing customer about existing business |
| Marketing | Promotions, offers, reactivation campaigns | Any message is promotional — this carries the strictest consent requirements |
| Mixed | Both of the above from one number | The realistic choice for most CRM users, and usually the right one |
| Low Volume Mixed | Same as Mixed, small volumes, fewer numbers | A single location sending modest volume — cheaper monthly, lower ceiling |
| 2FA / Account Notification | Login codes, transactional alerts only | Never mix promotional content in here — it is the fastest route to a revocation |
If you run appointment reminders and occasional offers from the same number, that is Mixed. Registering it as Customer Care because Mixed costs a little more is the kind of shortcut that surfaces months later as an audit.
The six reasons registrations get rejected
Rejections cluster tightly. In practice these six account for the overwhelming majority.
1. Legal name or EIN mismatch
The most common, and the slowest to resolve, because the fix may involve an IRS record rather than a form field. A missing "Inc.", an ampersand where the filing says "and", a DBA in place of the registered name — any of these fail the check. Copy the name from your EIN confirmation letter character for character.
2. No privacy policy, or one that ignores SMS
A generic policy that never mentions text messaging fails. It must state that phone numbers collected for SMS are not shared or sold to third parties for marketing purposes. This needs to be publicly reachable — not behind a login, not in a PDF.
3. Sample messages without opt-out language
Every sample should identify the sender and show the opt-out. A sample reading Your appointment is confirmed for Tuesday at 2pm gets rejected. Summit Dental: your appointment is confirmed for Tue 2pm. Reply STOP to opt out. passes.
4. A vague opt-in description
"Customers sign up on our website" is not enough. Describe the mechanism, quote the consent wording, and say where it appears: "Checkbox on the contact form at /contact, unchecked by default, reading: I agree to receive SMS updates from Summit Dental. Reply STOP to opt out."
5. Use case that contradicts the samples
Customer Care registered, promotional samples supplied. Reviewers compare the two, and this is the mismatch they check first.
6. A website that does not match the brand
A parked domain, a coming-soon page, or a site describing a different business than the one registered. The reviewer opens the URL. It has to corroborate the application.
Trust tier, throughput, and why approval is not the finish line
Approval gets you delivery. It does not get you volume.
Every registered brand sits in a trust tier derived from its verified identity — how completely the business could be corroborated in third-party records. That tier sets a daily cap on messages to each carrier's subscribers and a per-second sending rate. A low tier does not stop your messages; it meters them. Exceed the cap and the remainder queues or drops, usually in the middle of the campaign you cared most about.
This surprises people, because the tier has nothing to do with your message quality or your consent hygiene. It is about how legible your business is to a verification database. Older entities with a consistent public record and a matching website land higher; newly formed entities and sole proprietors land lower.
If your assigned tier is too low for your volume, external vetting is the route up: an independent vetting provider examines the business more thoroughly for a one-time fee and can return a higher score. For anyone running reactivation campaigns against a large list, this is usually worth doing before the first send rather than after the first throttle.
Timelines and what it costs
A clean registration, start to finish, is usually a week. Budget two if anything needs correcting.
- Brand registration: minutes to a few hours, automated.
- Campaign review: one to three business days typically; some use cases take longer.
- Number association: same day once the campaign is approved.
- External vetting, if needed: add several business days.
On cost, there are four separate charges and it helps to know the shape of them: a small one-time brand registration fee, a recurring monthly campaign fee that varies by use case (Low Volume Mixed is the cheapest tier, Marketing among the dearest), per-message carrier fees passed through on top of your provider's own rate, and an optional one-time external vetting fee if you pursue a higher tier.
The exact amounts are set by carriers and The Campaign Registry and are revised periodically, so take current figures from your provider's published pricing rather than from any article — including this one. What is stable is the structure: one setup charge, one monthly charge, ongoing per-message charges, and one optional upgrade.
What changes the day after you are approved
Registration is a standing obligation, not a certificate you file away. Four things become permanent.
STOP and HELP must work, always. STOP, END, CANCEL, UNSUBSCRIBE and QUIT have to suppress messaging to that number immediately and permanently until the person opts back in. HELP must return your business name and a contact route. Most platforms handle this natively — verify yours does rather than assuming.
Your samples become a commitment. Sending content materially different from your registered use case can cost you the campaign. If the programme changes direction, update the registration.
Consent records need to survive an audit. Keep what was agreed to, when, and through which form. If a complaint escalates, the record is the entire defence — and under the CTIA messaging principles the burden of showing consent sits with the sender.
Quiet hours still apply. Federal rules restrict marketing messages outside 8am to 9pm in the recipient's local time zone, and several states impose narrower windows. Note recipient's time zone — a 7pm send from California reaches a New Hampshire number at 10pm. Any competent platform schedules against the contact's zone; confirm yours is configured to.
None of this is exotic, but all of it is the sort of thing that is easy to leave switched off during setup and expensive to discover later. It is also, not coincidentally, the same discipline that keeps automated follow-up working at all: consent that is clean and provable is what keeps the channel open.
A 30-minute pre-flight audit
Run this before you submit anything. Six checks, half an hour, and it removes most of the failure modes above.
- Pull up your EIN letter and copy the legal name exactly as printed. Compare it to what you were about to type.
- Open your privacy policy in a private browser window. Search it for "SMS" or "text". If neither appears, it needs a paragraph before you go further.
- Find your opt-in and screenshot it. If you cannot point to a specific form field and quote its wording, the reviewer will not accept the description either.
- Write your samples with the sender name and the STOP line already in them, exactly as they will send.
- Read your samples against your chosen use case. If any of them promote anything, you need Mixed or Marketing.
- Load your website as a stranger would. Does it obviously belong to the legal entity on the application?
Six passes and you are ready to submit. Any fail is cheaper to fix now than after a rejection puts you back in the queue.
The bottom line
A2P 10DLC is not difficult, but it is unforgiving of guesswork, and it punishes the most easily: silently. The businesses that sail through are not the ones with compliance departments — they are the ones that spent twenty minutes matching a legal name to an IRS letter and adding a paragraph to a privacy policy before opening the form.
If you would rather not do any of it, that is reasonable too. Registration is part of what we handle on every plan — brand and campaign registration, carrier approval and ongoing monitoring — so the first you hear about it is that your messages are arriving. Either way, get registered before you start sending. The alternative is not a warning. It is a month of texts that never landed.
Frequently asked questions
Do I need A2P 10DLC registration if I only send appointment reminders?+
How long does A2P 10DLC registration take?+
What happens if I send messages without registering?+
Why do most A2P 10DLC registrations get rejected?+
Can a sole proprietor register for A2P 10DLC?+
What is a trust tier and how do I improve mine?+
Does my privacy policy really need to mention SMS?+
What are the SMS quiet hours I have to respect?+
References & sources
- The Campaign Registry — the central registry operating A2P 10DLC brand and campaign registration for US carriers.
- CTIA — messaging principles and best practices covering consent, opt-out handling and sender identification.
- Twilio A2P 10DLC documentation — carrier throughput tiers, use case definitions and current fee structure.
Carrier fees, throughput limits and review timelines are set by the carriers and The Campaign Registry and change periodically. Verify current figures with your messaging provider. This article describes registration mechanics and is not legal advice.