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US Short Code Keyword Requirements: HELP, STOP, and Opt-In Confirmation

All US-based Twilio short codes must respond compliantly to HELP and STOP keywords, regardless of whether the user sending the keyword is subscribed or not. This guide covers the response requirements and industry standards for US-based short codes, as well as some examples.

Short Codes 


NOTE: By default Twilio does not manage opt-outs or keywords for any provisioned short codes. If you would like to use Twilio for keyword and opt-out management you must use Advanced Opt-Out.


Per the Twilio Acceptable Use Policy, your company is required to comply with carrier regulatory requirements, industry standards, and applicable law. To comply with industry standards, your US short code must respond to keywords HELP and STOP. Any user who opts-out using STOP keyword must be added to an opt-out block list, and must not be sent any further messages until or unless they opt back in. The complete industry standards for US short codes HELP and STOP handling can be found in the CTIA Short Code Monitoring Handbook.

Notice: If you are using a short code with Messaging Services on Twilio, you can use Advanced Opt-Out to handle opt-outs instead of building your own system. With Advanced Opt-Out, you can customize your opt-out, opt-in and help keywords and responses, and let Twilio handle opt-out blocking on your behalf. For more information, see Getting Started with Advanced Opt-Out for Messaging Services.

Managing Opt-Out Requests

A compliance requirement for short code campaigns is allowing your recipients to opt-out of receiving text messages from your short code through any reasonable means. One means for opting-out of your campaign is by sending the keyword STOP, or equivalent keywords such as END, CANCEL, UNSUBSCRIBE, and QUIT to your short code.

When a user texts one of these keywords to your short code, your application must respond to that user’s request and manage the opt-out list. Unlike on long codes, Twilio is not involved in managing opt-out requests made via the STOP keyword. This allows your short code application to independently manage subscription lists and requests from end users to re-opt in. If you are unsure of how to implement this with your short code, please reach out to your account manager!


STOP Message

In addition to maintaining your opt-out list, industry standards require that a compliant response is sent whenever your end user text STOP or the universal keywords STOP, END, CANCEL, UNSUBSCRIBE, and QUIT to your short code, regardless of whether your recipient was subscribed to the program previously.


Short code response: You are unsubscribed from {Campaign Name} {Description} Alerts. No more messages will be sent. Reply HELP for help or {toll free number}.

HELP Messages

HELP Message Industry standards require that a compliant response is required whenever your recipients text the keyword HELP to your short code, regardless of whether the recipient is subscribed to the program.


Recipient message: HELP
Short code response: {Campaign Name} {Description} Alerts: Help at {source of help #1} or {toll free number}. Msg&data rates may apply. {Message frequency}. Text STOP to cancel.

Important Notes

  • The “description” should be a single word to define the kind of alerts, e.g. “Account Alerts,” “News Alerts,” “Promo Alerts,” etc.
  • The help source MUST either be a Toll-Free phone number or a support email address. Additional forms of help are allowed, but one OR the other of the above is required as a minimum.
  • The message frequency must be specific, but can be any interval, for example: “1 message per day,” “4 messages per month,” “2 messages per transaction,” etc. "Message frequency varies" is also allowed.

Audits and Compliance

The above guidelines are based on industry standards for short code service found in the CTIA Short Code Monitoring Handbook.

You should expect that your short code campaign will be audited at some point by a carrier or industry organization. In our experience, U.S. short code campaigns are typically audited for compliance with the CTIA Short Code Monitoring Handbook.

Nonetheless, please note that each carrier reserves the right to suspend short code service for any user at any time, so compliance with the above guidelines is not a guarantee against suspension of service by a carrier.

In addition to the above industry standards, there may be additional compliance requirements under U.S. law, including the Telephone Consumers Protection Act of 1991 (TCPA), depending on the nature of your text messaging campaign. These additional requirements may include providing additional means for your recipients to opt-out of your text message campaign beyond just replying STOP. You should consult with your legal counsel to ensure that your opt-out process is compliant with applicable law and consistent with industry standards.

For information on long code help and stop replies, please see Twilio support for opt-out keywords (SMS STOP filtering).

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