PIF – A Java library for finding atomic interactions and extracting geometric features supporting the analysis of protein structures

•PIF library calculates atomic interactions in protein structures.•Programmers and bioinformaticians can use PIF in their projects through the provided application programming interface.•PIF supports the drug development by filtering structures that indicate the lack of the biochemical properties desired by researchers.•PIF provides additional features describing protein geometry that can feed AI models.•PIF can be used in batch interaction calculations for collections covering many protein structures.