Missed-call text-back is an automatic text your business sends to someone whose call you didn't answer, usually within a minute, asking how you can help. It's legal when it's done properly: the texts go out from a number registered under A2P 10DLC, they stick to responding to that caller's request instead of marketing, they identify your business, and they honor STOP. This post explains those rules in plain English. It isn't legal advice, so if you're doing anything beyond simple customer-care texts, talk to a lawyer.
How does missed-call text-back work?
Your business line rings, nobody picks up, and the caller hangs up. Within about 60 seconds, the system sends them a text from your business number:
Hi, this is [Your Company]. Sorry we missed your call. What can we help with? Reply here or we'll call you back shortly. Reply STOP to opt out.
The caller can reply with the problem, book a time, or ask for a callback. You get the conversation in one place. The point is speed. A caller who hears nothing usually calls the next business on the list, and a short text keeps them with you.
What is A2P 10DLC?
A2P 10DLC stands for application-to-person messaging over 10-digit long codes, which are regular local phone numbers. It's the system U.S. carriers set up to verify businesses that send texts from software and to confirm that recipients agreed to get them. Twilio's A2P 10DLC overview describes it as the standard U.S. carriers put in place for this traffic.
Registration has two parts:
- Brand registration identifies the business sending the texts. Standard brands use a tax ID like an EIN. Twilio also offers a Sole Proprietor brand type for individuals, with lower limits.
- Campaign registration describes what you're sending and why (customer care, appointment reminders, marketing), how people opt in, and how they opt out and get help.
Do I need to register?
If you send texts to U.S. customers from a business texting platform over a regular local number, yes. Twilio's documentation says anyone sending SMS or MMS over a 10DLC number from an application to the U.S. must register, and that unregistered traffic gets additional carrier fees while registered traffic gets less filtering and more throughput.
In practice, unregistered business texts often just don't arrive, and you don't get an error. That's the worst kind of failure for text-back, because you think it's working while every missed caller hears nothing.
Does a missed call count as consent to text?
People get this part wrong more than any other.
The CTIA, the wireless industry group whose Messaging Principles and Best Practices carriers follow, treats a conversation the consumer starts as opt-in when the business replies only with responsive information. It also says that for informational messages, consent is given when the consumer provides their mobile number for that purpose. A phone call isn't a text, so missed-call text-back doesn't fit the "consumer texted first" case perfectly. The common practice is to treat the first text as a customer-care reply to the caller's own request:
- Send one text that responds to the call, without coupons, promotions, or links to sales.
- Identify your business by name.
- Include opt-out language, such as "Reply STOP to opt out."
- If they don't reply, a short, polite follow-up is reasonable. A long drip campaign to someone who never answered isn't.
- If you want to send marketing later, get separate, clear consent first, for example through a checkbox on a form.
Register your campaign as customer care, describe the missed-call flow honestly in the registration, and keep a copy of your opt-in description. Carriers review it.
What are the STOP rules?
The CTIA guidelines say standard "STOP" wording should be used for opt-out instructions, and that common opt-out words like stop, end, unsubscribe, cancel, and quit should be honored. Senders can send one confirmation of the opt-out and then nothing more.
The FCC has also tightened opt-out rules under the TCPA. Its revocation-of-consent rule, effective April 11, 2025, says consumers can revoke consent in any reasonable way, not only by texting a keyword. Opt-out requests must be honored within 10 business days, and a single confirmation text is allowed if it has no marketing in it and goes out within five minutes.
If someone says stop, in any words, stop texting them. Good texting software handles the keywords automatically. A person still has to catch "please don't text me anymore."
What gets businesses in trouble?
- Texting from an unregistered number and assuming it works.
- Sending promotions to people who only called with a question.
- Ignoring opt-outs that aren't the exact word STOP.
- Buying lists or texting people who never contacted you.
- Registering as one kind of campaign and sending something else.
What about review requests and appointment reminders?
Same rules. Appointment confirmations and reminders for a job the customer booked are customer-care messages. A review request after a completed job should go out under your registered campaign, identify your business, and include opt-out language. Keep it to one request and one reminder.
What Kedvezo handles
When Kedvezo sets up missed-call text-back, we register your brand and campaign, host the privacy policy and terms the carriers ask for, write the messages, set up STOP and HELP handling, and keep the texts to customer care. If you also have the AI receptionist, text-back catches the calls it doesn't, like hang-ups during the greeting. Texting goes live once the registration is approved, usually 1 to 3 weeks.
None of this is legal advice. It describes how the rules work in practice for simple customer-care texting, and your state may add its own rules on top.