Somewhere between deciding to text your customers and actually sending the first message, you run into the rules.
There's a registration form asking about your business. Something called 10DLC. Talk of consent, opt-outs, and record-keeping. Most of it is written for people who already understand it, which makes a straightforward setup feel like a legal minefield.
It isn't one. There are two systems to understand, a handful of things to get right, and most of it happens once during setup. This guide covers the whole picture in order: what registration is, what consent means, how opt-outs work, what records to keep, and which parts you have to handle yourself.
The two systems you need to understand
Almost all confusion here comes from mixing up two separate things.
Registration is about you. Carriers want to know which business is sending messages through their networks. You tell them who you are, what your business does, and what kinds of messages you'll send. This happens once, during setup.
Consent is about your contacts. Each person on your list needs to have agreed to hear from you, and you need a record of that agreement. This happens continuously, every time someone joins.
You need both. Registration without consent means you're a known business sending unwanted messages. Consent without registration means you have permission but your messages get blocked before they arrive.
Important
These two are often discussed as if they're one topic, which is why the whole subject feels harder than it is. Keep them separate in your head and each one becomes manageable.
What A2P 10DLC actually means
The name is unhelpful, so here it is in plain words.
A2P means application-to-person — messages sent by a business through software, rather than typed by a person on a phone. 10DLC means 10-digit long code, which is a standard US phone number, the kind your business already has.
Put together, A2P 10DLC is the system US carriers use to let businesses send messages from ordinary phone numbers. Before it existed, business messages and personal messages looked the same to carriers, and spam was hard to stop. Registration lets carriers tell the difference.
That's the practical benefit and the reason to take it seriously. Carriers now block unregistered business traffic outright. Not filtered, not delayed — blocked. Without registration, your messages don't arrive at all.
What registration asks for
Registration happens in two parts, and both are one-time setup steps.
- Register your business. Your legal business name, address, and tax ID (usually your EIN), plus a contact person. This has to match your official records exactly — a mismatch is the most common reason registrations get delayed.
- Register your campaign. What kinds of messages you'll send: appointment reminders, promotions, customer service replies. You'll also provide sample messages and describe how people join your list.
That second part is where registration and consent meet. You're telling carriers how people opt in, so it helps to have your sign-up method sorted before you register.
Pro Tip
Have your EIN and your exact legal business name ready before you start. Most delays come from small mismatches — a trading name instead of the registered name, or an address that doesn't match tax records.
What consent means in practice
Consent is permission to text someone. It sounds simple, and mostly it is.
Someone gives you their number and agrees to receive messages. That agreement should be clear rather than buried, specific about what they'll get, and given by them rather than assumed by you.
A few situations come up constantly:
- They filled in your web form and ticked a box to get texts. That's consent.
- They texted your keyword to join. That's consent, and it's the cleanest kind because the record is automatic.
- They gave you their number to book an appointment. That covers messages about the appointment. It doesn't automatically cover promotions.
- You bought a list. That isn't consent, and no platform will make it acceptable.
- They're an existing customer from three years ago. Depends entirely on what they agreed to at the time — which is exactly why records matter.
Consent covers what the person actually agreed to, and nothing more. If they signed up for appointment reminders, a weekend promotion is something different — and you'd need their agreement for that separately.
Keeping the record
Consent you can't show is consent you can't rely on. A record turns permission into something you can answer a question about.
A good record holds five things: who agreed, when, how they agreed, what wording they saw, and which form or keyword they came through. It gets saved at the moment someone joins, not reconstructed later — reconstruction is guesswork, and it shows.
Two questions come up constantly: how long to keep records, and what to do about older contacts you can't account for. Both are covered in the guide to what belongs in an SMS consent record.
When someone wants out
Every contact can leave, and when they do, the messages stop.
Carriers recognize a standard set of words — STOP, END, QUIT, CANCEL, UNSUBSCRIBE, REVOKE — in any capitalization. Someone who texts any of them has opted out. Plain-language requests like "please stop texting me" count too, even though they aren't standard keywords.
Four things follow: stop sending immediately, send one confirmation, record that they left, and leave a way back for anyone who changes their mind. The details, including what your confirmation should say, are in the guide to SMS opt-out rules.
AutoCampaign.ai Recommendation
Opt-outs arrive at night, on weekends, and mid-campaign when replies come faster than anyone can read them. This is the one part of compliance that shouldn't depend on a person noticing. Whatever platform you use, make sure removal happens automatically rather than by hand.
What the platform should handle
Not all of this is your job. A reasonable platform takes on most of the ongoing work.
What you handle: providing accurate business details for registration, deciding how people join your list, and writing sign-up wording that's honest about what you'll send.
What the platform handles: guiding you through registration, recording consent as contacts join, removing people the moment they opt out, and keeping both records in one place.
That split matters when you're comparing tools. Some platforms hand you a registration form and leave the rest to you. The practical question to ask is what happens at 11pm when someone texts STOP mid-campaign — how consent and opt-outs are handled automatically is a fair thing to check before you commit.
Five principles worth knowing
Nearly every rule in this guide traces back to a short set of principles from the CTIA, the association that sets US messaging standards:
- Don't send unsolicited messages
- Use proper opt-in methods
- Explain clearly what your recurring program involves
- Make opting out easy
- Keep content appropriate
Get these right and most of the specifics follow naturally.
This guide explains how registration and consent generally work and how the product handles them. It isn't legal advice. Requirements differ by state and by industry and they change over time, so check the specifics for your business with your own lawyer.
A realistic setup order
If you're starting from nothing, this order avoids the common backtracking.
- Decide how people will join your list — keyword, web form, or both
- Write your sign-up wording, saying plainly what they'll receive
- Gather your legal business name, address, and EIN
- Complete business and campaign registration
- Check that consent is being recorded automatically as contacts join
- Confirm opt-outs are removed without anyone doing it by hand
- Send a small first campaign before scaling up
Registration approval takes time, and anything unusual about your business takes longer. Start it well before your first planned send rather than the week of.
Why these rules are worth following
The terms sound complicated. What they ask for isn't. Tell carriers who you are. Only message people who agreed. Stop when they ask. Keep a record of both.
That's the standard most business owners would set for themselves anyway. The rules exist because enough businesses ignored it, and the carrier filtering that followed now affects everyone who sends messages.
There's a practical return for getting it right. Registered messages with proper consent are delivered more reliably than the alternative. Following the rules isn't only about avoiding trouble — it's how your messages reach the people who want them.
