Azure supports infrastructure as a service (IaaS), platform as a service (PaaS), and software as a service (SaaS). IaaS provides the basic building blocks for cloud computing, such as virtual machines and storage. PaaS provides a platform for building and running applications, without having to worry about the underlying infrastructure. SaaS provides applications that are hosted in the cloud and can be accessed on demand. These three categories provide a spectrum of options for businesses and developers to choose the level of control, management, and responsibility they want over their cloud-based resources and applications.