MCUViewer is an open-source graphical debugging tool for microcontrollers, featuring two core modules that allow developers to visualize and interact with microcontroller data in a non-intrusive way. The Variable Viewer module enables real-time monitoring, logging, and manipulation of variables through a debug interface (SWDIO, SWCLK, GND). Trace Viewer graphically represents real-time SWO trace outputs, offering deeper insights into high-speed data. The multiplatform tool requires either an STLink or a J-Link programmer for operation and will work for ARM-based and other types of microcontrollers that are compatible with either type of probe.