Can I configure default "unsubscribe" text at the end of my SMS blasts

There is currently no built-in feature that allows you to configure a standard opt-out message for SMS.

Please let us know if this is important to you and we can add it to our development list.

Please just note that adding this kind of standard opt-out message would contribute to the overall character count of SMS, thereby increasing SMS costs (as our carrier Twilio charges by SMS segment)

In the meantime, Twilio will still honour all of the standard incoming unsubscribe-style messages that people are used to sending. For example, if someone were to reply “STOP” or “UNSUBSCRIBE” then the system would honour those preferences.

Finally, if a supporter were to write back asking to opt out of SMS contact (but not use one of those standard unsubscribe phrases), you would see that via the SMS inbox and could unsubscribe them from within that thread using the “Update contact preferences” link.