This publication introduces the downhole dynamometer sensor technology for digitalizing sucker rod pumps' downhole behavior. The presented field application enables insight into the sensor principles, data evaluation processes and highlights the value chain. Sucker rod pumps (SRP) are used worldwide since the last century. Nevertheless, the system is still prone to fail in certain situations. The lack of measured downhole data is a severe problem that significantly slows down the innovation process. The presented downhole dynamometer sensor measurement system can successfully fill this gap and provides valuable, requested information. Each downhole dynamometer sensor records the three-dimensional stress field, the movement characteristics, and the produced fluid temperature. The recorded data allow a critical evaluation of the rod string behavior. Rod string loading and movement, friction forces between rod guides and tubing, and volumetric parameters can be evaluated. The recordings of several sensors are linked together to provide a comprehensive picture of the sucker rod string condition. The field case data analysis has indicated severe wear at specific positions of the sucker rod string and shown a significant optimization potential of the system. This publication shows the significant optimization potential for the tested sucker rod pumping system to postpone the economic limit and increase the recovery factor. The novelty is the wealth of information obtained and the associated detailed evaluation possibilities.