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10DLC glossary

What are STOP and HELP keywords?

STOP and HELP keywords
STOP and HELP are standard keywords people can text back to a business. STOP opts them out of messages, and HELP returns a reply with the program name and how to reach support. The Campaign Registry prefills opt-out keywords with STOP and help keywords with HELP, and CTIA says senders should also honor natural wording like cancel or unsubscribe.

Definition: STOP and HELP keywords are standard text replies that let a consumer opt out of an SMS program (STOP) or get program and support information (HELP).

These keywords give people control. Anyone who gets your texts should be able to leave at any time or ask who you are. Carriers check that your campaign handles both.

What are the keyword rules?

Source What it says
CTIA 5.1.3 honor opt-outs at any time, use standard STOP wording, honor natural language, send one final opt-out confirmation
TCR guide opt-out keywords prefilled with STOP; help keywords prefilled with HELP; opt-out and help messages are mandatory for most campaigns
47 CFR 64.1200(a)(10) replies like stop, quit, end, revoke, opt out, cancel, or unsubscribe revoke consent; honor within a reasonable time, no more than 10 business days
Bandwidth opt-out language must include at least one of END, STOP, UNSUBSCRIBE, or CANCEL
Twilio 30890 help message needs brand name plus phone or email

TCR lists subscriber opt-out as mandatory for every campaign except 2FA and Machine to Machine.

Where should STOP and HELP appear?

  • In your opt-in call-to-action next to the checkbox.
  • In your SMS terms on your website.
  • In your first opt-in confirmation text.
  • In at least one sample message, as Twilio error 30893 suggests for opt-out language.

Why it matters for your website

Providers like Telnyx, Vonage, and Plivo ask for Reply STOP and Reply HELP instructions in your call-to-action and your SMS terms page. If those pages skip them, reviewers can flag your campaign. See SMS terms requirements.

Related terms: Opt-in, A2P, Campaign use case

Sources

Our SMS terms pages include STOP and HELP language by default. See pricing, or check your site at /check.

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Frequently asked questions

Do I have to honor opt-out words other than STOP?

Yes. CTIA says senders should honor natural language like stop, end, unsubscribe, cancel, and quit, and federal rules list words including stop, quit, end, revoke, opt out, cancel, and unsubscribe.

How fast must I stop texting someone who opts out?

Under 47 CFR 64.1200(a)(10), a revocation must be honored within a reasonable time not to exceed 10 business days. This is not legal advice, so check with your counsel.

What should my HELP reply say?

Twilio error 30890 says the help message needs your brand name plus a phone number or email address for support.

Can I send a message after someone texts STOP?

CTIA says you should send one final confirmation that the person has been opted out, and then stop.

What counts as SMS opt-in consent?

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What is a 10DLC campaign use case?

A 10DLC campaign use case is the category you pick for your texts, like Marketing or Account Notifications. See TCR's standard and...

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