For achieving a deeper understanding of PEM and DMFC fuel cells is the measurement of the current density distribution. The operation of a fuel cell is impacted by a complex array of physical and electrochemical influences. These influences are not homogeneous throughout the cell and vary depending on the micro-environment at any given point within the cell. A thorough understanding of the cell's current distribution is critical in designing MEA, GDLs and bipolar plates that maximize fuel cell performance. TrueData-CDD allows measuring the local-dissolved current density distribution. The measuring data provide the researcher with information about optimal control and operation strategies. Integrated in the Evaluator testing systems it enables the systematic determination of stacks and fuel cell systems. TrueData-CDD is controlled by our FuelWork software. For custom-build test equipment, the software tool CurrentVIEW can be used to control the device and display the measured data.