What are the opt-in requirements for US short codes?

Users can opt-in to a short code campaign several ways: by sending a text message or opting in from a mobile app (Handset Opt-In), or by signing up on a web site, filling out a paper form, making a verbal agreement, or otherwise opting in without using a handset (Non-Handset Opt-in).  In each case, the campaign’s opt-in message flow must meet certain compliance standards set by the wireless carriers.

The following guidelines are based on carrier conditions of short code service and other industry standards. Your company is required to comply with these guidelines in the use of any Twilio-provided short code. Please note, each carrier reserves the right to suspend short code service for any user at any time.

Handset Opt-In

When a user signs up from a mobile handset, a double opt-in process is advised, but not required. A compliant message flow should look like this:

End user: {Keyword}
Short code: Welcome to {Campaign Name} {Description} Alerts! Msg&data rates may apply.  {Message frequency} Reply HELP for help, STOP to cancel.

• The “description” should be a single word to define the kind of alerts, e.g. “Account Alerts,” “News Alerts,” “Promo Alerts,” etc.
• 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. If the message frequency will vary based on user interaction, “1 message/user request” is standard.

Non-Handset Opt-in

When a user initially signs up by any means other than from a mobile handset, a double opt-in process is required. A compliant message flow should look like this:

(User signs up without using mobile handset, and receives a text message from the short code asking to confirm opt-in)
Short code: Text YES to join {Campaign Name} {Description} Alerts. Msg&data rates may apply. {Message frequency} Reply HELP for help, STOP to cancel.
End user: YES
Short code: Welcome to {Campaign Name} {Description} Alerts! Msg&data rates may apply.  {Message frequency} Reply HELP for help, STOP to cancel.

Note: Rather than confirming opt-in with a text message keyword such as YES, users may confirm by entering a verification code online instead. Once the verification code has been entered, a compliant welcome message must be sent to the handset.