STOP, HELP and opt-outs: what every business text must honor

What the federal rule says about stopping

We read the rule's own text. Paragraph (a)(10) of 47 CFR 64.1200 says a person may revoke consent "by using any reasonable method to clearly express a desire not to receive further calls or text messages." It then makes three things concrete.

• Seven words always count. Replying with "stop," "quit," "end," "revoke," "opt out," "cancel," or "unsubscribe" is treated as a reasonable way to revoke consent.
• Other ways count too. The list is not the limit. "Any reasonable method" is the test, so a customer who says it on the phone or writes "please take me off your list" has also asked.
• There is a deadline. A request must be honored "within a reasonable time not to exceed ten business days."

Ten business days is the outer limit, not a target. A customer who replies STOP and gets another offer the next morning will not care what the rule allows. The consent side of the same rule is explained in our consent guide.

The one text you may send after STOP

Paragraph (a)(12) of the rule allows a single confirmation text after an opt-out, on two conditions: it only confirms the request, and it contains no marketing. If it is sent within five minutes, the rule presumes it falls within the consent the person had already given.

So this is fine:

• "Northside Plumbing: you are unsubscribed and will get no more texts from us."

And these are not: a discount to stay, a question asking them to reconsider, or a second reminder a day later. Keep the confirmation to one part as well; the counting rules are in why a text is 160 characters. (Northside Plumbing is a made-up name for the example.)

What your texting provider does automatically

Businesses do not send texts straight to the phone network. They go through a provider, and providers handle the standard words for you. We read two providers' documentation to see exactly what happens.

• Twilio lists its default English opt-out words for local numbers as STOP, UNSUBSCRIBE, END, QUIT, STOPALL, REVOKE, OPTOUT and CANCEL, matched in capitals or lower case. When one arrives, the number goes on a blocked list and later messages to it fail with error code 21610.
• Telnyx recognizes stop, stopall, stop all, unsubscribe, cancel, end and quit. The number goes on an opt-out list and Telnyx sends an automatic reply that begins "You have successfully been unsubscribed."

Notice the two lists are not identical, and neither is the same as the rule's seven words. That gap is your job, not the provider's. How providers and carriers fit together is covered in what is A2P 10DLC.

Where automatic handling falls short

Three gaps are worth knowing, because each one is a way to text someone who asked you to stop.

• The word has to stand alone. Telnyx's documentation is direct about it: "stop all" is recognized, but "please stop all messages" is not. A person has to read those replies.
• Blocks can be per number or per group of numbers. Telnyx applies the block across the numbers on one messaging profile; numbers on a different profile can still reach that person. If you text from more than one number, check that an opt-out on one covers them all.
• Requests arrive in other ways. A phone call, an email, a note on an invoice. None of these touch your provider's list unless someone adds the number by hand.

The fix is a habit, not software: someone reads every reply, and anyone on your team can add a number to the opt-out list the same day. A single place for replies helps; that is the idea behind a lead inbox.

What HELP should return

HELP is the other reserved word. Twilio's documentation notes that "help" is a reserved keyword that cannot be removed, and that the reply is whatever help message you set. Its registration guide says the help message "may include the Brand name and additional support options."

A good HELP reply answers two questions: who is texting me, and how do I reach a person?

• "Northside Plumbing: for help call 555-0142 or email [email protected]. Reply STOP to end texts."

One detail from Twilio's page: a person who has already opted out will not get the help reply. That is by design. Our own help wording is on the text message consent page.

Opting back in

People change their minds, and the block works in both directions. Both providers we read reserve START and UNSTOP as the words that lift it. Telnyx adds a catch: the person must send the word to the exact number they opted out from, and it then confirms with "You have successfully been re-subscribed to this number."

What you should not do is lift a block yourself because a customer "probably" wants texts again. Let them send the word, or collect a fresh opt-in the way the consent guide describes.

A short checklist

1. Every first text names your business and says "Reply STOP to end."
2. You know where your provider keeps its opt-out list and how to add a number by hand.
3. One opt-out covers every number you text from.
4. A person reads replies each working day.
5. Your STOP confirmation is one text with no offer in it.
6. Your HELP reply has your name and a real way to reach you.
7. Opt-outs are never deleted, even when a customer record is.

NewFrontDesk's text-back is built on these rules: its own opt-out list for each business, kept permanently. It is in test mode and sends nothing yet; details are on missed-call text-back. Questions? Call (346) 913-7215 or request setup.

Sources

• 47 CFR 64.1200, paragraphs (a)(10) and (a)(12): revoking consent and the confirmation text (Cornell Legal Information Institute copy)
• Twilio Docs: Advanced Opt-Out (default keywords, blocked list, error 21610, help keyword)
• Telnyx: SMS opt-out keywords and stop words
• Twilio Docs: A2P 10DLC registration fields (opt-out and help messages)

Sources read on October 9, 2026. The regulation is quoted from the Cornell Legal Information Institute's copy, which listed its latest amendment as August 29, 2025. Provider behavior changes; the provider's page is the final word. General information, not legal advice.