Opt-out keywords
How Proxy handles opt-out and opt-in keywords
By default, Twilio handles opt-out and opt-in keywords as described in Twilio support for opt-out keywords (SMS STOP filtering) document; when Twilio receives an opt-out keyword from an external sender phone number to any Twilio number, Twilio will reply with a pre-generated response and will no longer send messages from the Twilio Number to that external phone number until the sender opts back in by sending an opt-in keyword.
When using SMS with Proxy, there are special considerations and deviations from the standard handling of opt-out and opt-in keywords:
1. Proxy will not forward STOP, UNSUBSCRIBE, END, CANCEL, QUIT, STOPALL, ARRETT, ARRET, ARRETE (opt-out) messages from either participant. Dropped messages do not trigger callbacks.
2. Proxy forwards all opt-in, help and info keywords between Participants, except UNSTOP, to ensure that potentially valid messages are not lost.
3. For any opt-in/out message not forwarded, Proxy will send a debugger notification with Twilio code 80901.
4. Proxy does not support the Advanced Opt Out feature available with Messaging Services.
5. Unlike with a Messaging Service, opt-out keyword replies will not apply to the entire pool of phone numbers in a Proxy Service pool.
6. If you would like Proxy to respect the STOP SMS Filtering flag, contact our support team to submit a request to enable the ProxyRespectSmsStopFilterFlag account flag. Once Twilio enables this, custom opt-in/out keyword handling can be accomplished by adding the desired logic to Proxy's InterceptCallbackUrl.
Need some help?
We all do sometimes; code is hard. Get help now from our support team, or lean on the wisdom of the crowd by visiting Twilio's Stack Overflow Collective or browsing the Twilio tag on Stack Overflow.