Twilio Blaster sends through your Twilio account. Twilio can reject sends after supported opt-out keywords, but you still need to maintain your contact permissions and honor other requests to stop.
How Twilio opt-outs work #
For supported SMS routes, recognized keywords include STOP, STOPALL, UNSUBSCRIBE, CANCEL, END and QUIT. Blocking is associated with the sender or Messaging Service; it is not a universal carrier-level block across every number and channel.
Sender type, country and Advanced Opt-Out settings affect the behavior. Alphanumeric sender IDs cannot receive replies, so they need another usable opt-out method.
What appears in Twilio Blaster #
An attempted send to an opted-out recipient can return Twilio error 21610. A generic HTTP 400 error can have other causes; read the error details. Twilio Blaster does not read incoming replies or keep an automatic opt-out list inside Excel.
What to do with opt-outs #
Record requests to stop and exclude those recipients from later campaigns. Do this for ordinary language requests as well as keywords. Do not switch sender numbers or channels to get around a request.
For someone who explicitly asks to resume, follow Twilio’s supported opt-in process for the relevant sender or Messaging Service. Removing a row locally does not undo a Twilio block, and changing your list does not replace consent.
Related guidance: https://help.twilio.com/articles/223134027-Twilio-support-for-opt-out-keywords-SMS-STOP-filtering-.