The tutorial describes how to create an alert system using Twilio SendGrid and Node.js to monitor air quality parameters in an IoT system. The system can send email notifications when the temperature or PM10 concentration exceeds predefined threshold limits. The tutorial covers two approaches: data-push and data-pull, where the data-push approach involves exposing a REST endpoint for external data producers to push data into the system, and the data-pull approach involves pulling data from an external sensor layer service at regular intervals. The tutorial provides code examples and configuration settings for both approaches, demonstrating how to implement the alert system using Node.js and Twilio SendGrid.