By default, Twilio automatically handles
START, and other reserved keywords when users text them into your Twilio long code phone numbers. This is to help ensure that your messaging app complies with recommended practices for the commercial use of SMS. Twilio returns standard replies to these keywords.
For details on Twilio’s keyword handling, including the default replies, please see Twilio support for opt-out keywords (SMS STOP filtering).
You can customize your keywords and responses, including adding additional languages or country-specific configurations, using the Advanced Opt-Out feature for Messaging Services.
Advanced Opt-Out for Messaging Services
Users of Messaging Services are able to customize and modify the
HELP and more opt-in and opt-out keywords and standard replies for their services. Users can add and remove keywords, languages, and the keyword responses for each Messaging Service.
Advanced Opt-Out changes apply to all phone number members of a Messaging Service, including short codes.
For more details, please see Getting Started with Advanced Opt-Out for Messaging Services.
By default, Twilio does not handle
STOP keyword replies, or the opt-out list for standalone short codes. Short code customers who are not using Messaging Services will need to build this functionality into their short code messaging application, in accordance with industry standards.
Short code customers who are using their short code number within a Messaging Service can use Advanced Opt-Out to customize keywords and responses. However, you should take care to ensure your keyword responses are compliant and match what was approved in your short code application.
For information on carriers’ requirements for short code
STOP replies, please see the following resources: