- A missed-call text back replies by text to a caller you couldn't answer, so the conversation can carry on by message.
- Keep the first text to one message: say who you are, offer help, and say how to opt out. Save offers for people who've agreed to receive them.
- US law treats texts as calls. Marketing texts generally need written consent, opt-outs must be honored within 10 business days, and the law allows damages of $500 per violation.
- Carriers block business texts from unregistered numbers, so registration comes before the first message.
A customer calls. You're with another customer, so the call goes unanswered. A few seconds later they get a text from you asking how you can help. That's missed-call text back. It's simple and it's popular, and it's worth setting up properly, because texting customers comes with rules. This guide covers both halves. It's general information, not legal advice.
Why it works
Callers don't wait, and fewer than half leave a message. In a CallRail survey of 1,000 US consumers, 78% said they had abandoned a business after an unanswered call, and only 42% said they leave a voicemail.
Calling back later has its own problem. Pew Research found that eight in ten Americans don't generally answer their cellphone when an unknown number calls. A text that arrives straight after their own call is easy to recognize and easy to answer.
What the first message should say
One message, sent promptly, that does four things: names your business, acknowledges the call, offers a next step, and says how to opt out.
- During the day: "Hi, this is [Business]. Sorry we missed your call. How can we help? Reply here or call us back at [number]. Reply STOP to opt out."
- After hours: "Hi, this is [Business]. We're closed right now and back at [time]. Tell us what you need and we'll pick it up then. Reply STOP to opt out."
Leave out discounts, offers, and anything else that reads as an advertisement. The reason is in the next section.
The rules, in plain English
- Texts count as calls. The Federal Communications Commission has said so for years: text messages are "calls" subject to the Telephone Consumer Protection Act.
- Consent depends on the kind of message. The FCC's consumer guide puts it in one line: commercial texts require written consent, and for informational texts consent may be oral. The mobile carriers' own best practices use three levels. A reply to a customer who texted you first needs no extra permission. Informational texts, such as appointment reminders, need the customer's agreement. Promotional texts need agreement in writing.
- Opt-outs must be honored. Under the FCC's rules, a customer can revoke consent by any reasonable method, and you must honor it within a reasonable time, not more than ten business days. You may send one text confirming the opt-out, with no marketing in it.
- Mind the clock. The same rules bar telephone solicitations before 8 am or after 9 pm in the customer's local time. Some states are stricter. Florida's cutoff for sales calls is 8 pm, and Florida requires prior express written consent for sales calls and texts sent with an automated system.
- The penalties add up. The federal law allows $500 in damages for each violation, and up to three times that if the violation was willful.
So is a missed call permission to text back?
No rule answers that in so many words. The FCC has said that an "on demand" text sent in response to a consumer's request isn't a violation, but that was about customers who had asked for a text. The carriers' guidelines treat a reply as conversational when the customer texted first. Neither mentions missed calls.
That's why the careful version looks the way it does: one reply, sent promptly, that names the business, helps with the call the person just made, sells nothing, and offers a way to stop. Anything beyond that first reply should wait until the customer has agreed to it. If you operate in a state with stricter rules, or you're unsure, ask a lawyer before you switch it on.
Register before you send
There's a practical step too. US carriers require businesses that text from ordinary ten-digit numbers through software to register who they are and what they send. The system is called 10DLC, and it involves registering your business as a "brand" and your use of texting as a "campaign." It isn't optional in practice: one large messaging provider notes that unregistered traffic has been blocked across the industry since February 1, 2025.
Your texting provider usually handles the paperwork. Allow time for it before you plan to go live.
Reminders, follow-ups, and texts to past customers
These are where consent matters most, because you're the one starting the conversation.
- Ask at the right moment. When a customer books, buys, or fills out a form, ask whether they'd like reminders by text. For promotions, get it in writing with a checkbox they tick themselves.
- Keep the record. The carriers' guidelines recommend keeping when and how each customer agreed.
- Say who you are and how to stop, every time it's not obvious.
- Don't buy lists. The same guidelines say not to text lists that were rented, sold, or shared.
Email plays by different rules
US federal law doesn't require consent in advance for marketing email, which is why campaigns to past customers often start there. It has its own requirements. Among those in the Federal Trade Commission's CAN-SPAM guide: honest sender details and subject lines, a clear statement that the message is an ad, a valid physical postal address, a clear way to opt out, and opt-outs honored within 10 business days.
A short checklist
- Register your business and your texting use with your provider before sending.
- Keep the missed-call reply to one message with no offers in it.
- Name your business and include "Reply STOP to opt out."
- Collect consent before reminders, and written consent before promotions.
- Honor every opt-out, however it's worded.
- Keep promotional texts inside daytime hours in the customer's time zone.
- Check your state's rules, or ask a lawyer to.
Sources
- CallRail, survey of 1,000 US consumers, September 2025
- Pew Research Center, December 2020 (10,211 US adults)
- Federal Communications Commission, declaratory ruling and order, Federal Register, October 2015
- Federal Communications Commission, "Stop Unwanted Robocalls and Texts"
- 47 CFR 64.1200 and 47 U.S.C. 227
- CTIA, Messaging Principles and Best Practices, May 2023
- Florida Statutes 501.059 and 501.616
- Twilio, A2P 10DLC documentation, July 2026
- Bandwidth, 10DLC frequently asked questions, August 2026
- Federal Trade Commission, "CAN-SPAM Act: A Compliance Guide for Business"
