PaaS: Platform as a Service (PaaS) is a form of cloud computing model that delivers applications over the Internet. In a PaaS model, a cloud provider delivers hardware and software tools - usually those needed for application development - to its users as a service. A PaaS provider hosts the hardware and software on its own infrastructure. As a result, PaaS helps users from having to install in-house hardware and software to develop or run a new application. What developers gain with PaaS is a framework they can build upon to develop or customize applications.
PaaS makes the development, testing, and deployment of applications quick, simple, and cost-effective. With this technology, enterprise operations, or a third-party provider, can manage OSes, virtualization, servers, storage, networking, and the PaaS software itself. Developers, however, manage the applications.