While often nebulously defined, "the cloud" typically refers to the global network of computer servers on which computation is executed non-locally. Cloud based tools (sometimes referred to as applications, apps, services, or micro-services) described here are broadly algorithms or functions which take user input communicated via web protocols (such as HTTP ), process this data on demand, and return the output to the user in a presentable fashion (i.e., in a graphical web browser). Examples of such tools for materials scientists range from state of the art ML models to predict material properties , and vast libraries of DFT calculations , to simple utilities that assert the charge neutrality of a chemical formula .