What is A2P 10DLC? A plain-English guide to business texting in the US
If your business sends texts to US customers from a normal 10-digit phone number, carriers expect you to be registered for A2P 10DLC. Here's what that means, without the jargon.
The name, decoded
A2P stands for application-to-person: messages sent by software, like a CRM, booking system or marketing tool, rather than a person typing on a phone. 10DLC means 10-digit long code, which is simply a standard local US phone number.
Why carriers require it
US mobile carriers introduced 10DLC registration to cut down on spam. Registering tells them who is sending, what kind of messages they send, and how customers agreed to receive them. Registered traffic is treated as trusted. Unregistered traffic is filtered, blocked or restricted.
Who needs to register
- Businesses sending appointment reminders, confirmations or follow-ups by text
- Anyone sending promotions or SMS marketing campaigns
- Agencies texting on behalf of clients
- Any software that sends texts to US numbers from a 10-digit number
What registration involves
There are two parts. First your brand: your legal business name, EIN, address and website. Then your campaign: what you'll send, sample messages, and how people opt in and opt out. Both are reviewed before your number can send at full volume.
The bottom line
Registration is now part of texting customers in the US. Getting the details right the first time is what avoids weeks of back-and-forth. We handle the whole registration for you, including fixing rejections.
Campaign rejected? 7 reasons A2P 10DLC campaigns fail, and how to fix them
A rejected campaign usually comes down to a handful of fixable details. Resubmitting without fixing the cause just sends you back to the end of the queue, so start here.
1. Business details don't match
Your legal name, EIN and address must match official records exactly, and match what's on your website. Even small differences in spelling or suffixes like LLC can cause a rejection.
2. No privacy policy or SMS terms
Reviewers look for a privacy policy that says mobile numbers aren't sold or shared, and terms that describe your SMS program: what you send, how often, that message and data rates may apply, and how to reply STOP or HELP.
3. Opt-in isn't clear
Every form that collects phone numbers should have an unticked consent checkbox with clear wording. Pre-ticked boxes or consent hidden in general terms are red flags.
4. Sample messages are incomplete
Samples should look like real messages, name your business, and include an opt-out such as "Reply STOP to opt out".
5. The use case doesn't match
If you register for appointment reminders but your samples are promotions, expect a rejection. Choose the campaign type that matches what you'll actually send.
6. The website isn't ready
A site that's under construction, missing contact details, or doesn't show your business clearly is a common reason for rejection.
7. Restricted content
Some industries face extra scrutiny or aren't allowed on standard campaigns. Check your content is permitted before you submit.
Send us your rejection reason and we'll fix the cause and resubmit for you.
SMS marketing compliance checklist for small businesses
Texting is one of the most effective ways to reach customers, and one of the easiest to get wrong. Use this checklist before every campaign. It's a practical guide, not legal advice.
Consent
- Only text people who clearly agreed to receive texts from you
- Use an unticked checkbox with plain wording on every form
- Keep a record of when and how each person opted in
- Never text bought, rented or scraped lists
Opt-out
- Include "Reply STOP to opt out" in marketing messages
- Honour STOP requests immediately and permanently
- Answer HELP replies with who you are and how to get support
Message content
- Identify your business in the message
- Keep promotions honest and clear
- Use links on your own domain where you can, rather than public link shorteners
Timing and frequency
- Send during reasonable hours in the recipient's time zone
- Tell people how often to expect messages, and stick to it
Registration
If you text US numbers from a 10-digit number, make sure your brand and campaign are registered for A2P 10DLC. Our bulk SMS platform handles opt-outs automatically.
SMS segments explained: why your text might cost twice as much
Texts are billed by segment, not by message. A message that looks short can quietly use two or three segments, doubling or tripling the cost of a campaign.
How segments work
Using standard characters (the GSM-7 set), one segment holds up to 160 characters. Longer messages are split, and each part then holds 153 characters, because a little space is used to join the parts back together.
The emoji trap
Add a single emoji, a curly quote or certain accented letters and the whole message switches to Unicode. Now one segment holds only 70 characters, and 67 per segment after that. A 100-character message with one emoji costs two segments instead of one.
How to keep costs down
- Swap curly quotes (’ “ ”) for straight ones (' ")
- Leave emojis out of large campaigns, or budget for the extra segment
- Remember the opt-out line counts toward your length
- Cut filler words and use a short link
Check before you send
Our free SMS segment checker shows the character count, encoding, segments and estimated cost of any message, with the opt-out line included.
Missed-call text-back: turn unanswered calls into booked jobs
When you can't pick up, most callers don't leave a voicemail. They call the next business on the list. Missed-call text-back gives you a second chance in seconds.
How it works
When a call goes unanswered, the system automatically sends the caller a text, for example: "Sorry we missed your call! How can we help?" The caller replies by text, and the conversation lands in your inbox, ready for you or an AI agent to answer.
Why it works
- It's instant, so the caller hasn't moved on yet
- Texting is easier than waiting on hold or calling back
- Every missed call becomes a contact in your CRM, not a forgotten number
Make it even better
- Personalise the text with your business name
- Let an AI agent reply, answer questions and book the appointment
- Use different messages for after-hours and busy-line calls
Getting started
Missed-call text-back works on your existing business number. It's included with calling on Glymore AI, and you only pay for the messages and minutes you use.
How an AI receptionist books appointments 24/7
An AI receptionist answers your messages and calls the moment they arrive, any time of day, and books appointments straight into your calendar. Here's how it works in practice.
It's trained on your business
The agent learns your services, prices, opening hours, policies and common questions. When someone asks "How much is a cleaning?" it answers with your real price, not a generic reply.
It works across channels
The same agent can reply on WhatsApp, SMS, your website chat and even phone calls, so customers can reach you however they prefer.
It books real slots
Connected to Google Calendar, Outlook or your CRM calendar, it only offers times you're free, books the appointment, sends a confirmation and schedules reminders.
It knows when to hand over
Complaints, emergencies or anything it isn't sure about go straight to your team with the full conversation, so a human is always in control.
Is it right for you?
If you lose leads to slow replies, after-hours enquiries or missed calls, an AI receptionist usually pays for itself quickly. See the Glymore AI agent in action, from $197 per month.
How to choose a CRM for your small business: 8 things that matter
The right CRM saves hours every week and stops leads slipping through the cracks. The wrong one becomes an expensive address book. Look for these eight things.
1. One inbox for every channel
Texts, WhatsApp, Facebook, Instagram, email and website chat in one place, so nothing gets missed.
2. A visual pipeline
See every lead by stage and know exactly who to follow up with today.
3. Automation
Follow-ups, reminders and review requests should send themselves.
4. Calendar booking
Let customers book online, with reminders that reduce no-shows.
5. AI built in
An AI agent that replies instantly turns more enquiries into appointments.
6. Payments and invoices
Taking payments where you manage the customer saves time and chasing.
7. Integrations
Make sure it connects to the tools you already use. See our integrations.
8. Real support
Setup, training and someone to call matter more than a long feature list.
Glymore AI combines all eight in one system, built and set up for you. Book a free demo to see it on your business.
