ESA's BIOMASS mission is designed to provide, for the first time from space, P-band Synthetic Aperture Radar measurements to determine the amount of above ground biomass (AGB) and carbon stored in forests. The novelty of BIOMASS’s sensors poses the challenges to develop scientific algorithms, estimating i.e. ESA’s AGB data product, with limited data pre-launch and for timely improvement of operational algorithms with the mission launch in 2023. The BIOMASS Product Algorithm Laboratory (BioPAL) is an open-source scientific project, supporting the development of official BIOMASS mission algorithms coded in Python. The goal of BioPAL is to bridge the gap between advancements in scientific algorithm development and fast integration into ESA’s BIOMASS’s ground operations. It is the first time that official processing algorithms for an ESA mission are released publicly and supported by open and collaborative development within the scope of an open-source software project and community.