UPIMAPI takes as input either a list of UniProt IDs or a blast file from annotation using UniProt database as reference and uses UniProt's API to retrieve information relative to those IDs. It is essentially a command line implementation of UniProt's ID mapping web service available at https://www.uniprot.org/uploadlists/, allowing for retrieval of information from thousands of IDs in one go, while still relying on the web service.