Does Twilio support STOP, BLOCK, and CANCEL (aka SMS STOP Filtering)?

Yes. By default, Twilio will handle the following messages on long codes in accordance with industry standards:

  • STOP, STOPALL, UNSUBSCRIBE, CANCEL, END, and QUIT will stop customers from receiving messages from that Twilio number. Only single-word messages will trigger the block. Further, the block works and is logged even if your number currently has no messaging request URL.
  • START and YES will opt customers back in to the messages coming from your Twilio phone number, and these messages will also be delivered to your Twilio account so you can update your application logic.
  • HELP and INFO will return a message informing the customer that they can use the above commands to control the delivery of messages.

If you have further questions on this, please contact us. For information on short code HELP and STOP responses, please see this article.