How to Track Opt-Outs in PHP

Summary

This tutorial demonstrates building a PHP application that records customer opt-out preferences from SMS replies using Twilio’s Incoming Message Webhook and Event Streams, which require PHP 8.5, Composer, and SQLite. When the SMS body is an opt-out keyword such as STOP, START, or HELP, Twilio includes an OptOutType parameter in the webhook request, which the application checks using strcasecmp and array_first. The application, based on the Twilio Slim Base project, stores the opt-out status and account SID in an SQLite database via PHP-DB and laminas-servicemanager, using a TableGateway for the user_optouts table. The handleWebhook() function validates the OptOutType against class constants (OPT_OUT_TYPE_START, OPT_OUT_TYPE_STOP, OPT_OUT_TYPE_HELP) and inserts a record before returning a TwiML response. Twilio already blocks further messages for standard opt-outs, but local recording enables advanced actions like syncing a CRM; the tutorial covers bootstrapping, configuring Twilio messaging services with Advanced Opt-Out, using ngrok, and verifying with an SQL query.

Takeaways

1. 1

   Twilio’s Incoming Message Webhook and Event Streams include an OptOutType parameter when the SMS body is an opt-out keyword like STOP, START, or HELP.

2. 2

   Recording opt-out preferences locally in a database allows advanced actions such as keeping a CRM in sync, beyond Twilio’s built-in blocking.

3. 3

   The application uses PHP-DB with laminas-servicemanager to store opt-out records in an SQLite table, and the handleWebhook() function validates the OptOutType against class constants.

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