This paper presents gnss lib py, a Python library used to parse, analyze, and visualize data from a variety of GNSS (Global Navigation Satellite Systems) data sources. The gnss lib py library's ease of use, modular capabilities, testing coverage, and extensive documentation make it an attractive tool not only for scientific and industry users wanting a quick, out-of-the-box solution but also for advanced GNSS users developing new GNSS algorithms. Metadata Metadata for the gnss lib py library is included in the ancillary data table 1. 1. Motivation and significance Global Navigation Satellite Systems (GNSS) are used globally for positioning, navigation, and timing across industries such as transportation, agriculture, power systems, and finance [1]. Several countries and political entities have developed global and regional satellite constellations such as GPS and WAAS (United States), GLONASS (Russia), BeiDou (China), Galileo (the European Union), QZSS (Japan), and IRNSS (India). GNSS technology, policy, and services are an active research area with established research journals and technical conferences.