The tutorial discusses how to send SMS reminders using Laravel Lumen and the Twilio API. It covers creating a subscribers table, seeding data into it, defining relationships between models, sending SMS reminders, and scheduling a command to run daily. The code includes various classes such as `EventReminderClient`, `SendSmsReminderCommand`, and `SubscriberTableSeeder`. The tutorial also provides guidance on how to use the Twilio API to send messages and how to schedule a command to run at regular intervals.