This tutorial uses Twilio's Node.js Module and the Twilio Rest Message API to build a real-time SMS voting application using Node.js. The app is designed to scale to thousands of votes per second and millions of total votes, making it suitable for large-scale events. To achieve this, the authors denormalized event and vote data, allowing them to tweak how they handle persistence. They used CouchDB's range queries to fetch information on an event and its votes, ensured against people voting more than once using CouchDB's _id mechanism, and implemented simple caches and flush operations using CouchDB's bulk operations. The app is built using Node.js, Twilio's Rest Message API, and CouchDB, with a focus on scalability and performance.