XRebel is an always-on performance tool for development that runs with your web app. It displays alerts in your browser when discovering issues. XRebel provides real time insight into your application performance metrics and issues - while you code.
From here you have access to the XRebel user documentation, listing proper installation procedures as well as usage scenarios. In addition, you can find a complete list of all browsers, servers and JDBC drivers currently supported by XRebel.