This thesis is centered around the development and application of a digital platform for passive behavioral human subject research.This platform named Behapp (https://behapp.com), developed at the University of Groningen, makes use of mobile ‘apps’ to passively record various attributes related to social and explorative behavior through the smartphones of research participants. The resulting data is detailed, objective and can be received on a longitudinal basis without active input from the participant. It is expected that such a detailed perspective on behavior may contribute significantly to our understanding of various diseases. Feeling (un) well is often closely related to one’s social and explorative behavior.An important and recurring theme of this thesis is the responsible application of this type of research technology. The resulting data is privacy sensitive which is the reason why initially an assessment is made from a legal, technical and organizational perspective to serve as input for the design of the Behapp platform. Once in service quality control comes into view, measurements must accurately reflect real-world behavior. However, mobile platforms such as android evolve rapidly, not always without consequences to data quality. Therefore, continuous evaluations of data quality are deemed a necessity. Lastly, against the backdrop of the pandemic a pre- / post- lockdown comparison of behavior was made over various studies. Here the Behapp platform fulfills one of her primary design goals, to uncover significant changes in behavior.