BIMS is an open-source platform for serving, analysing and sharing biodiversity data, built on top of the Django framework. It started as the Freshwater Biodiversity Information System (FBIS) in South Africa and has since grown into a family of portals across Africa and beyond, supporting water resource managers, conservation agencies and researchers. One of the long-running public instances is freshwaterbiodiversity.org. BIMS is a multi-tenant application, so a single deployment can host multiple, independent biodiversity portals on the same codebase.