SageMath is an open-source mathematics software system that is licensed under the GPL. It is a free alternative to popular mathematical software systems like Magma, Maple, Mathematica, and Matlab. SageMath builds on top of existing open-source packages such as NumPy, SciPy, matplotlib, Sympy, Maxima, GAP, FLINT, and R, among others. Users can access the combined power of these packages through a common, Python-based language or directly via interfaces or wrappers. SageMath offers various resources to help users learn how to use the software, including books, tutorials, forums, and a FAQ section. Additionally, SageMath provides a feature tour that showcases its quickstart, research, and graphics capabilities. The software has a dedicated library section that includes testimonials, books, publications, and a press kit. Users can support SageMath by becoming a sponsor, and donations are handled through the SageMath GitHub Organization, with Open Source Collective as the fiscal host.