SMS opt-out keywords: STOP, HELP and what counts as a stop
13 min readRules and vendor lists read 2026-10-22
For the owner or ops lead whose business texts customers: the reply words the FCC's rule treats as a stop, the keywords carriers expect, which of those words 14 messaging APIs and texting platforms act on by themselves, and what your team has to catch by hand. Every rule and every vendor list was read at its source on 2026-10-22.
The short answer
Two rule books decide what a reply does. The FCC's rule says which replies end consent and how fast you must act. CTIA's carrier guidelines say which keywords your number answers. Your texting tool sits between them, and it rarely covers all of either.
The seven words in the FCC rule
Since 2025-04-11 the FCC's rule names the reply words that end consent without any argument about what the person meant. It covers marketing and informational texts alike:
“Any revocation request made using an automated, interactive voice or key press-activated opt-out mechanism on a call; using the words “stop,” “quit,” “end,” “revoke,” “opt out,” “cancel,” or “unsubscribe” sent in reply to an incoming text message; or pursuant to a website or telephone number designated by the caller to process opt-out requests constitutes a reasonable means per se to revoke consent.”
“Per se” means the word settles it: once someone replies with one of the seven, consent “is considered definitively revoked”. Two of them, REVOKE and OPT OUT, are missing from many tools' keyword lists, so they are the first two to test on your own number.
Everything that is not one of the seven
The list is a floor. A reply in other words must be treated as a revocation “if a reasonable person would understand those words to have conveyed a request to revoke consent.” “Please stop texting me”, “take me off your list” and “wrong number, don't text me” all qualify. Requests that reach you another way count as well: a voicemail or an email to a number or address meant to reach you creates a rebuttable presumption that consent was revoked (§ 64.1200(a)(11)).
Two more lines in the same paragraph matter to texting teams. If you send from a number that cannot take replies, every text has to say so and give another way to opt out. And today you “may not designate an exclusive means to request revocation of consent”: you cannot tell customers that only STOP works.
The one confirmation text
After a stop, the rule allows exactly one more message, and CTIA expects it. Both describe the same text.
“If the confirmation text is sent within five minutes of receipt, it will be presumed to fall within the consumer's prior express consent.”
The text may only confirm the request: no marketing or promotional content, and nothing else sent after it. If it takes longer than five minutes, the sender has to show the delay was reasonable. If the person had agreed to several kinds of texts, the confirmation may ask whether the stop covers all of them; until they answer, you stop every text that needs consent. CTIA's Messaging Principles ask for “one final opt-out confirmation message per campaign” and nothing after it (§ 5.1.3).
Most tools send this text for you. Twilio's default reads “You have successfully been unsubscribed. You will not receive any more messages from this number. Reply START to resubscribe.” On toll-free numbers and on some platforms the carrier's own “NETWORK MSG” goes out instead, and you cannot edit it. If you write your own, keep it to your business name, that no more texts will come, and how to rejoin; the SMS opt-in language builder drafts the STOP and HELP replies with the opt-in messages, so the wording matches.
STOP, HELP and START on the carrier side
Carriers enforce CTIA's Messaging Principles through 10DLC vetting and filtering. Their keyword list is older and shorter than the FCC's, and it is written as guidance rather than law, and a program that ignores it risks having its traffic filtered.
CTIA asks senders to “state in the message how and what words effect an opt-out” and to use standardized “STOP” wording for the instruction. It then names stop, end, unsubscribe, cancel, quit and “please opt me out” as normal language that should “also be read and acted upon”, and says capitalisation, punctuation and letter case should not change whether an opt-out counts (§ 5.1.3). The full CTIA picture is in the CTIA messaging guidelines guide; here is how the two lists line up, word by word.
| Reply | FCC rule | CTIA | In the tools |
|---|---|---|---|
| STOP | Ends consent per se | The standard opt-out instruction; listed as normal language | Every tool in the table below acts on it, except Bandwidth long codes; Sinch once consent management is on |
| QUITENDCANCELUNSUBSCRIBE | Each ends consent per se | Named as normal-language opt-outs to act on | On most lists; Sinch's default list has only STOP and UNSUBSCRIBE |
| REVOKE | Ends consent per se | Not among CTIA's examples | Not on the published lists of Telnyx, Sinch, Plivo, SlickText, EZ Texting, SimpleTexting or Quo |
| OPT OUT | Ends consent per se | CTIA's example is the phrase "please opt me out" | Not on Telnyx's, Sinch's, Plivo's, SimpleTexting's or Quo's lists; Twilio lists OPTOUT, one word |
| STOPALLUNSUBREMOVE | Not named; the reasonable-person test applies | Not named; read and act on normal language | Each on some lists, never on all |
| HELPINFO | Not a revocation | Answer with the program name and how to reach you (Handbook § 3.4) | The person stays subscribed |
| STARTUNSTOP | Not in the rule | Not named in the Principles | The re-subscribe words almost every provider accepts |
HELP is not STOP
HELP asks for information, not an exit. CTIA's short code handbook sets the minimum reply: answer “with the Program name and further information about how to contact the Message Sender” (§ 3.4), and 10DLC reviewers expect the same. Twilio, Telnyx, Plivo, SlickText, SimpleTexting, Klaviyo and RingCentral answer it automatically; Twilio, Plivo and Klaviyo also answer INFO. A reply such as “help me stop these” is a different matter: it is a sentence asking to stop, and it goes to a person.
One trap on toll-free numbers: Twilio says that once a person has opted out, their HELP and INFO texts are not delivered until they opt back in. A customer who replies HELP after STOP is still opted out.
START and UNSTOP: coming back
A person who texted STOP can rejoin by texting START or UNSTOP to the same number. Providers add their own: Twilio also takes YES on long codes, Plivo takes YES, RESUME and GO, RingCentral SUBSCRIBE, RESUME and CONTINUE. Twilio's toll-free numbers accept only START and UNSTOP, and its help centre adds that the START has to go to the same sender the STOP went to. Bandwidth's toll-free network layer accepts UNSTOP and START.
Treat a rejoin as a new opt-in and keep it beside the old opt-out: CTIA asks senders to “retain and maintain all opt-in and opt-out requests in their records” (§ 5.1.5). And never pick a join keyword that is also an opt-out or help word: a sign-up word like “END” opts people in and out in one text. The opt-in language builder flags those words.
Keyword coverage: what each provider and platform catches
The seven FCC words down the side, the tool across the top. “Yes” means the tool's own page names the word as an automatic opt-out. “No” means the page says the tool does not act on it: no opt-out handling at all, or exact or single-word matching against a list that leaves the word out. “Check with the vendor” means the page is silent, or an optional reader might catch it: not named is not the same as not honoured, so test it.
Messaging APIs
If your developers send through an API, the provider's defaults are the only automatic layer you have. The longer comparison of these providers is in best SMS API providers.
| Reply | Twilio | Telnyx | Bandwidth | Sinch | Plivo |
|---|---|---|---|---|---|
| STOP | Yes | Yes | No | Yes | Yes |
| QUIT | Yes | Yes | No | No | Yes |
| END | Yes | Yes | No | No | Yes |
| REVOKE | Yes | Check with the vendor | No | No | No |
| OPT OUT | No | Check with the vendor | No | No | No |
| CANCEL | Yes | Yes | No | No | Yes |
| UNSUBSCRIBE | Yes | Yes | No | Yes | Yes |
| A full sentence ("please stop texting me") | No | Yes | No | No | No |
| Answers HELP by itself | Yes | Yes | Check with the vendor | Check with the vendor | Yes |
Texting and SMS marketing platforms
Platforms usually add their own layer on top of the carrier network. Four of them read plain sentences by default or as a setting; the rest leave sentences to your team. Full feature comparisons are in best SMS marketing software and best text messaging service for business.
| Reply | SlickText | EZ Texting | SimpleTexting | Klaviyo | Omnisend | Attentive | Postscript | Quo (formerly OpenPhone) | RingCentral |
|---|---|---|---|---|---|---|---|---|---|
| STOP | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| QUIT | Yes | Yes | Check with the vendor | Yes | Yes | Yes | Yes | Yes | Yes |
| END | Yes | Yes | Check with the vendor | Yes | Yes | Yes | Yes | Yes | Yes |
| REVOKE | Check with the vendor | Check with the vendor | Check with the vendor | Yes | Yes | Yes | Yes | No | Yes |
| OPT OUT | Yes | Yes | Check with the vendor | Yes | Yes | Yes | Yes | No | Yes |
| CANCEL | Yes | Yes | Check with the vendor | Yes | Yes | Yes | Yes | Yes | Yes |
| UNSUBSCRIBE | Yes | Yes | Check with the vendor | Yes | Yes | Yes | Yes | Yes | Yes |
| A full sentence ("please stop texting me") | Yes | Check with the vendor | Check with the vendor | Yes | Yes | No | Yes | No | Check with the vendor |
| Answers HELP by itself | Yes | Check with the vendor | Yes | Yes | Check with the vendor | Check with the vendor | Check with the vendor | Check with the vendor | Yes |
Each vendor's own help page, read 2026-10-22; sources at the foot of the page.
How each tool matches, and the way back in
Matching rules decide the edge cases. A single-word rule (Twilio, Quo) ignores “STOP PLEASE”; an exact-match rule (Sinch) ignores “stop now please”; Omnisend counts CANCEL and REVOKE anywhere in a reply.
| Tool | How replies are matched | Other opt-out words named | Back in with |
|---|---|---|---|
| Twilio | Handled by default on long codes. The help centre says only single-word replies trigger the block ("STOP PLEASE" does not); short codes need Advanced Opt-Out. | STOPALL, OPTOUT (one word) | START, YES, UNSTOP; toll-free numbers only START and UNSTOP |
| Telnyx | Default keywords block at once. AI opt-out detection, a messaging-profile setting, treats a high-confidence plain reply like STOP. | STOPALL, STOP ALL | START, UNSTOP |
| Bandwidth | No opt-out handling on long codes or short codes. Toll-free enforces STOP at the network layer; the lists are yours to keep. | Toll-free only: STOP and the French ARRET forms | Toll-free only: UNSTOP, START (and French forms) |
| Sinch | Consent management is switched on per app. Exact match only ("stop now please" does not trigger it); the default English list is editable. | STOP MARKETING, STOP NOTIFICATION (per message type) | START, SUBSCRIBE |
| Plivo | Case-insensitive keywords on long codes and toll-free; "Hey, can you stop texting me?" is listed as an invalid opt-out. | UNSUB, STOP ALL | START, YES, RESUME, UNSTOP, GO (one word) |
| SlickText | Listed words always opt out. Opt-Out Intelligence, switched on separately, reads every reply and can opt the contact out. | REMOVE | Not described on the page read |
| EZ Texting | Its help pages name different word sets; other wording is opted out by hand from the inbox. | REMOVE, "take me off your list" | Not described on the pages read |
| SimpleTexting | STOP unsubscribes and adds the number to the Local Block List; other words are not described. | None named | UNSTOP (the network reply says so) |
| Klaviyo | All seven since 2025-04-11, plus unsubscribe detection, on by default for US numbers. | STOPALL | START, UNSTOP |
| Omnisend | Most keywords must start the reply; CANCEL and REVOKE count anywhere in it. AI intent detection for US traffic. | OPTOUT, OPT-OUT, STOPALL | JOIN, SUBSCRIBE, START (its sign-up keywords) |
| Attentive | The seven keywords act at once. Other opt-out phrasing gets a text asking the person to reply STOP, without opting them out. | None named | Not described on the page read |
| Postscript | The seven keywords plus "fuzzy" phrases such as "take me off this list" and "wrong number". | STOP ALL, NO MORE | An active keyword, pop-up, QR code or form |
| Quo (formerly OpenPhone) | Single-word replies only ("STOP PLEASE" does not count); the block covers every Quo number on the account. | STOPALL | START, UNSTOP |
| RingCentral | Not case-sensitive. Opt-outs are kept per pair: that business number and that customer. | French ARRÊT | START, SUBSCRIBE, RESUME, CONTINUE, UNSTOP |
Find your tool's gaps
Pick the tool you send through. The panel lists the words it acts on by itself, what it leaves to your team, and the short list of work that closes the gap.
Which words does your tool leave to you?
Pick the tool your texts go out through.
Acts on by itself
STOPQUITENDREVOKECANCELUNSUBSCRIBE
Left to your team
- OPT OUT No
- A full sentence: No
To do
- Add OPT OUT as opt-out keywords if the tool lets you; if it does not, an inbox rule or a daily read has to catch them.
- Have a named person read every reply that is not a keyword, each business day, and opt out anyone who is asking to stop, with the date.
- Carry each opt-out to every other number, system and list that texts or calls the person, within 10 business days of receipt.
Twilio: Handled by default on long codes. The help centre says only single-word replies trigger the block ("STOP PLEASE" does not); short codes need Advanced Opt-Out.
Then test it on your own number before the first send, because settings and lists change: text each of the seven words from a staff phone, rejoining with START between tests, then one typo and one plain sentence. Keep the date and the results; they show the process worked on that day. To see how the rule reads a specific reply, the reply tester in the texting rules guide sorts it into the right branch.
Replies in plain words: who reads them
No keyword list covers how people actually say stop. The rule's reasonable-person test needs a reader, and for most businesses that reader is a person on the team, with a routine.
The carriers ask for the same. For short code programs CTIA's handbook makes it a requirement, not a suggestion:
“Message Senders must scan Message Originator message logs regularly to identify opt-out attempts and must terminate those subscriptions, regardless of whether the subscribers used the correct opt-out keywords or methods.”
What to treat as a stop
“Please stop texting me”, “take me off this list”, “who is this, don't text me again” and “wrong number” are requests to stop. “Can you stop by at 5?” and “cancel my appointment” are not, which is why a person reads these rather than a keyword filter. When a reply is genuinely unclear, treat it as a stop: one lost subscriber costs less than one text after a revocation.
The tools give you the manual path. EZ Texting's inbox has an “Opt Out Contact” action for people who “don't use the automatic opt-out words”; Postscript's Responses page has an Opt Out button on each reply; Klaviyo lets you remove consent by hand and asks you to review its automatic calls. Reach differs too: Quo blocks every number on the account, while RingCentral keeps opt-outs per pair of numbers, so someone has to carry each RingCentral opt-out to your other lines; the OpenPhone alternatives comparison walks through that case tool by tool.
If the texts are telemarketing, the do-not-call rules reach them as well (§ 64.1200(e)): an internal do-not-call request is honoured within 10 business days and kept for 5 years (§ 64.1200(d)(3), (d)(6)). The do not call rules guide covers that list.
Every rule on this page was read at its primary source on the date shown, and every vendor list on the vendor's own page. Lists change, so re-test your number when your tool updates. This is not legal advice.
Questions owners ask
Is STOP the only word I have to honour?
No. 47 CFR § 64.1200(a)(10) names seven reply words that revoke consent on their face: stop, quit, end, revoke, opt out, cancel and unsubscribe. Any other reply counts too "if a reasonable person would understand those words to have conveyed a request to revoke consent", and every request has to be honoured within a reasonable time not to exceed ten business days.
My texting tool does not catch "revoke" or "opt out". Am I covered?
Not by the tool. The rule counts those two words whatever your software does with them, so either add them as opt-out keywords (most tools let you) or have someone read unmatched replies every day and opt those people out by hand, with the date.
Can a customer opt out by email, phone call or voicemail?
Yes. Under § 64.1200(a)(11) a voicemail or an email to a number or address meant to reach you creates a rebuttable presumption that consent was revoked once the person shows the request was made. CTIA's Messaging Principles also ask senders to support opt-out by "phone call, email, or text" (§ 5.1.3).
Can I text someone after they reply STOP?
Once. A one-time confirmation with no marketing in it is allowed, and sent within five minutes it is presumed to fall within the person's consent (§ 64.1200(a)(12)). If they agreed to several kinds of texts, that one message may ask whether the stop covers all of them; until they answer, stop every text that needs consent.
What should the reply to HELP say?
CTIA's short code handbook sets the floor: answer HELP "with the Program name and further information about how to contact the Message Sender" (§ 3.4). Most programs add how to opt out, the message frequency and the rates line. HELP is not an opt-out, so the person stays subscribed.
How does someone opt back in after STOP?
Usually by texting START or UNSTOP to the same number they stopped. Twilio's toll-free numbers accept only START and UNSTOP, and YES does not undo a toll-free block. Keep the date of the new opt-in with the old opt-out: CTIA § 5.1.5 asks senders to keep all opt-in and opt-out requests.
Sources
- 47 CFR § 64.1200(a)(10)–(12), revocation of consent (eCFR, current as of 2026-10-20)fetched 2026-10-22
- FCC, Report and Order and FNPRM FCC 26-67 (adopted Sept. 30, 2026)fetched 2026-10-22
- FCC, Order DA 26-12 (Jan. 6, 2026), revoke-all delay to Jan. 31, 2027fetched 2026-10-22
- Federal Register, FCC documents (checked for FCC 26-67 publication)fetched 2026-10-22
- CTIA, Messaging Principles and Best Practices (May 2023), §§ 5.1.3, 5.1.5fetched 2026-10-22
- CTIA, Short Code Monitoring Handbook v1.9 (effective 2023-08-02), §§ 3.3.4, 3.4, 3.8.2 and glossaryfetched 2026-10-22
- Twilio help centre: Twilio support for opt-out keywords (SMS STOP filtering)fetched 2026-10-22
- Twilio Docs: Advanced Opt-Out for Messaging Servicesfetched 2026-10-22
- Telnyx Docs: Advanced opt-in/out managementfetched 2026-10-22
- Bandwidth: Does Bandwidth handle opt-in and opt-out keywords?fetched 2026-10-22
- Sinch Docs: Conversation API consent managementfetched 2026-10-22
- Plivo Docs: DND servicefetched 2026-10-22
- SlickText help: Tools to help you stay compliantfetched 2026-10-22
- EZ Texting help: What are opt-out numbers and how can I view them?fetched 2026-10-22
- EZ Texting help: Deleting contacts vs opting out contactsfetched 2026-10-22
- EZ Texting: Frequently asked questionsfetched 2026-10-22
- SimpleTexting: What is a STOP response?fetched 2026-10-22
- SimpleTexting: What is a HELP response?fetched 2026-10-22
- Klaviyo: April 11 SMS opt-out compliance changefetched 2026-10-22
- Klaviyo: Understanding your text message settings (keyword responses)fetched 2026-10-22
- Omnisend: Compliance: meet TCPA requirements for SMS marketing in US/CAfetched 2026-10-22
- Attentive: Fuzzy opt-outsfetched 2026-10-22
- Postscript: How Postscript protects your shop with automatic subscriber removalsfetched 2026-10-22
- Postscript: Subscriber opt-out compliancefetched 2026-10-22
- Quo support: Opt-outfetched 2026-10-22
- RingCentral support: Understanding SMS opt-out managementfetched 2026-10-22