Mathics3 is a free, open-source alternative to Mathematica, featuring a modular design and Mathematica-compatible syntax and functions. It relies on various Python libraries and has different components, including a core, a command-line client, and a web server. The project is licensed under the GNU General Public License and is developed by a community of volunteers. Mathics3 can be installed using a Docker image or by installing the Mathics-omnibus Python package.