SMS Standard Keywords
Introduction
U.S. mobile phone carriers reserve certain one-word keywords as standard consumer commands within SMS messaging campaigns. These SMS keywords can be categorized as follows:
Opt-out: STOP, END, CANCEL, QUIT, UNSUBSCRIBE
Customer care: HELP, INFO
These keywords cannot be modified or repurposed: these keywords and their use are described in industry regulations defined by U.S. mobile phone carriers and the Cellular Telephone Industries Associated (CTIA).
Per industry regulations, SMS campaigns must support these standard SMS keywords and provide compliant responses. The following section describes these keywords in greater detail.
Standard keywords
REMINDER: The following SMS keywords are carrier-reserved and industry standard. These keywords cannot be modified or repurposed, and SMS campaigns must include them to comply with industry regulations.
Opt-out
Main keyword: STOP
Universal keywords: STOP, END, CANCEL, QUIT, UNSUBSCRIBE
Description: The SMS campaign should send an opt-out message after consumers text a keyword indicating that they wish to opt-out. This opt-out message should confirm that the consumer has been opted out of the campaign or service.
Customer care
Main keyword: HELP
Universal keywords: HELP, INFO
Description: The SMS campaign should respond to HELP with a message containing the service provider's name and additional cotact information.
Further reading
CTIA Short Code Monitoring Handbook: Version 1.8; current as of writing (1.31.22)
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