A customer replies with one word: STOP.
It's a small moment, and it's easy to get wrong. Miss it and you keep texting someone who asked you not to. That's how complaints start, and complaints are how a business number gets blocked.
The rules here are simpler than most people fear. This guide covers what has to happen when someone opts out, the words that trigger it, what your confirmation should say, and how to make sure none of it depends on a person remembering.
What an opt-out actually is
An opt-out is a customer withdrawing permission to text them.
That's the whole idea. They said yes at some point — by texting a keyword, filling in a form, or checking a box. An opt-out is them changing their mind. From that moment, your marketing messages to that number have to stop.
Two things make this different from an email unsubscribe. It happens instantly, not after a delay. And it isn't a preference you can talk them out of. It's a line you don't cross.
The words that trigger an opt-out
STOP is the one everybody knows. It isn't the only one.
Carriers recognize a standard set of words, and they work whether or not you list them: STOP, END, QUIT, CANCEL, UNSUBSCRIBE, and REVOKE. Case doesn't matter. A customer who texts "stop" in lowercase has opted out.
Two more words matter, though they aren't opt-outs:
- HELP — the customer wants support info. Reply with your business name and how to reach you.
- START or UNSTOP — the customer wants back in. This re-subscribes them.
Important
A customer might not text a clean keyword. They might write "please stop texting me" or "take me off this list." Those aren't standard keywords, so a system may not catch them. Watch for them, and treat them the same way.
What has to happen when someone opts out
Four things, in order.
- Stop sending immediately. Not at the end of the campaign. Not tomorrow. The next message should never go out.
- Send one confirmation. A single reply telling them it worked. This is the only message you send after an opt-out, and it's expected.
- Record it. Keep a note of who opted out and when. If anyone ever asks, that record is your answer.
- Leave a way back. If they want to rejoin later, they should be able to — usually by texting START or joining again the normal way.
What your confirmation message should say
Keep it short and warm. Confirm it worked, name your business, and leave the door open.
[Business Name]: You're unsubscribed and won't get any more messages from us. Text START anytime to rejoin.That's three things: confirmation, who you are, and the way back.
Avoid two temptations. Don't ask them to reconsider — that reads as ignoring the request. And don't add an offer. A discount code in an opt-out confirmation is a marketing message sent to someone who just asked you to stop.
Do this, not that
Do
- Act on every opt-out request, even one that isn't a standard keyword
- Send exactly one confirmation, then nothing
- Keep a record of who opted out and when
- Include an opt-out line in your first message to a new contact
- Let people rejoin easily if they change their mind
Don't
- Ask why they're leaving, or try to win them back in the confirmation
- Add an offer or promotion to the confirmation
- Move the contact to a different list and keep texting them
- Wait until a campaign finishes to remove them
- Rely on someone checking replies by hand
This guide explains how opt-outs generally work and how the product handles them. It isn't legal advice. For rules specific to your business or state, check with your own lawyer.
Why automatic handling matters
Think about when opt-outs actually arrive. Evenings. Weekends. In the middle of a campaign, when replies come in faster than anyone can read them.
A person handling this well needs to see every reply, recognize every phrasing, and remove the contact before the next send. That's a lot to ask on a busy day, and it only takes one miss.
When the system removes people on its own, it happens the same way every time — at 2am, mid-campaign, on a holiday weekend. Consent is recorded as contacts join, and opt-outs are applied the moment they arrive, which is how consent and opt-outs are handled at the platform level rather than by anyone on your team. If replies do need a human, they land in a shared team inbox instead of one person's phone.
Pro Tip
Opt-out language belongs in the first message a new contact ever gets, not just the campaigns. If you use a keyword to collect sign-ups, build it into the welcome reply so every contact sees it from day one. That's part of setting up text-to-join properly.
Opt-outs protect your list
It's tempting to see an opt-out as a loss. A contact gone. The list a little smaller.
Flip it around. Someone who doesn't want your messages was never going to book anything. What they might do is mark you as spam. Enough of those, and carriers start filtering your messages — including the ones going to people who do want them.
So an opt-out is a small loss that prevents a much bigger one. A list of 800 people who want to hear from you is worth more than 1,000 where 200 are annoyed.
AutoCampaign.ai Recommendation
Five compliance principles from the CTIA.
The industry association that sets US messaging standards holds to five basics: no unsolicited messages, proper opt-in methods, a clear explanation of your recurring program, easy opt-out, and appropriate content. Get these right and opt-out handling mostly takes care of itself.
The one thing worth checking
Look at your current setup and ask a simple question. If a customer texts "stop texting me please" tonight at 11pm, what happens?
If the answer is "someone would see it in the morning," you have a gap. It's easy to close, and worth closing before it costs you a complaint.
