ZeroTurnaround's XRebel is a performance tool for Java Web Apps that provides real-time performance insights to understand and resolve potential issues faster and earlier during the development phase. It integrates with various message queues and databases, including Couchbase, offering a comprehensive overview of all calls made to the backend each time a request is sent to the server. XRebel can be tried by downloading the latest version from ZeroTurnaround's website, deploying it as a Java Agent in JVM configuration, or using Maven with Spring Boot applications. Once deployed, XRebal logs call details and provides access to its dashboard where users can view stacktraces and Couchbase operations. The tool also sends notifications when the trial license is about to expire, prompting users to renew their license.