Cree is a modern toolbox that allows researchers to design and conduct economic experiments. Cree places very few restrictions on the devices facing subjects. Thus Cree experiments can be run in a myriad of settings, including laboratories, but also in extra-laboratory settings such as classrooms, workplaces, or over the Internet. Cree is a framework that provides the tools to handle many of the otherwise mundane, complicated or manually tasks required to set up and run economic experiments.