This document describes debugging techniques for Mule applications, including the Studio Visual Debugger, troubleshooting, and logging. The Visual Debugger allows setting breakpoints to inspect message contents at different points in a flow. To use it, set breakpoints, run in debug mode, and view message data. Troubleshooting techniques include configuring stacktraces, debugging outside Studio by enabling remote debugging, and using log statements. Logging is useful to follow an application's state by tracking messages through the flow.