Pyteomics is a collection of lightweight and handy tools for Python that help to handle various sorts of proteomics data. Pyteomics provides a growing set of modules to facilitate the most common tasks in proteomics data analysis, such as: - calculation of basic physico-chemical properties of polypeptides: - mass and isotopic distribution - charge and pI - chromatographic retention time - access to common proteomics data: - MS or LC-MS data - FASTA databases - search engines output - easy manipulation of sequences of modified peptides and proteins The goal of the Pyteomics project is to provide a versatile, reliable and well-documented set of open tools for the wide proteomics community. One of the project's key features is Python itself, an open source language increasingly popular in scientific programming. The main applications of the library are reproducible statistical data analysis and rapid software prototyping. WWW: https://pyteomics.readthedocs.io/ WWW: https://github.com/levitsky/pyteomics