The article provides an in-depth look at a tool designed to monitor Couchbase Mobile Sync Gateway's changes feed, offering insights into its implementation using JavaFX and various Java libraries. The tool is intended to help developers write sophisticated business logic by examining the changes feed, and it includes a detailed walkthrough of the code structure, including major classes and methods. The application features a Controller class that integrates UI components with backend functionality, utilizing listeners for real-time updates and synchronization. The text explains how the tool manages document lists, live queries, and user interactions, while also discussing the use of a database helper class for replication and authentication tasks. Additionally, a Sync Gateway Monitor class is highlighted for tracking changes feed using OkHttp, emphasizing the importance of capturing sequence values for efficient feed monitoring. The article serves not only as a technical guide for building and understanding the app but also as a resource for developers seeking to enhance their proficiency with Couchbase Mobile and JavaFX.