SMS Opt-Out Keywords and Stop Words

Messaging (SMS/MMS) SPAM

Are you receiving unwanted SMS/MMS messages? You can stop those annoying messages directly from our Webclient or mobile app.

What are SMS Opt-Out Keywords?

Callicity automatically processes incoming messages and recognizes English-language stop words. Stop words are specific words such as STOP or UNSUBSCRIBE that signal that a person no longer wishes to receive messages from you.


When Callicity identifies a stop word, the person's phone number is added to the opt-out list, and you will no longer be able to send messages to that number. Any further messages from your account that are sent to a number on the opt-out list will not be processed.


Callicity recognizes the following English-language stop words:

  • stop

  • stopall

  • stop all

  • unsubscribe

  • cancel

  • end

  • quit

Note: Stop words are only recognized if they are the only words in the message. For example, “stop all” is recognized but “please stop all messages” would not be recognized.


To restart messages, the number that opted out has to send any of the following opt-in keywords to the exact same number they opted out from:

  • start

  • unstop

Note:  Blacklisting phone numbers prevents voice calls, not SMS/MMS messages.

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