Unipept is an open source web application developed at Ghent University that is designed for metaproteomics data analysis with a focus on interactive datavisualizations. Unipept is powered by an index containing all UniProt entries, a tweaked version of the NCBI taxonomy and a custom lowest common ancestor algorithm. This combination enables a blazingly fast biodiversity analysis of large and complex metaproteome samples. This functionality is also available via an API and a set of command line tools. Next to these core functions, Unipept also has a tool for selecting unique peptides for targeted proteomics and for comparing genomes based on peptide similarity.