This tutorial teaches how to build a NodeJS app that celebrates special anniversaries in the life of a loved one using Twilio Programmable Voice. The app requires a free Twilio account, Node.js version 14.16 or above, and various dependencies such as dotenv, twilio-node, moment, and node-cron. The user is prompted to set up their Twilio account by obtaining an Account SID, Auth Token, and phone number, which are then used to create a .env file with these details. An anniversary list is created in the form of a JSON file, where each entry contains the title of the anniversary, date, frequency, and message. The app fetches anniversaries on a daily basis using cron scheduling and places an outbound voice call to the partner's phone number if there's a match with the current date. The call is made using Twilio Markup Language (TwiML) with a predefined message. After making the call, the anniversary date is updated based on its frequency.