Spring Boot is an application framework that simplifies the development of production-grade Spring-based applications, allowing developers to quickly set up sites with real-time features using WebSockets and Pub/Sub paradigms. This tutorial provides a comprehensive guide to implementing a collaborative TODO list application using Spring Boot, WebSockets, and Ably for Pub/Sub messaging. The application leverages Spring Data JPA for database interactions, Thymeleaf for dynamic HTML content, and various REST controllers to handle client requests. By integrating Ably, the tutorial demonstrates how to achieve efficient real-time updates across clients without overloading the server. The project is further enhanced by containerizing it with Docker, making it easily deployable and scalable. The tutorial concludes with a preview of a future tutorial on implementing a robust authentication system using Auth0.