Platform as a Service (PaaS) is a paradigm for delivering operating systems and associated services over the Internet without downloads or installation. PaaS is sometimes called "cloudware" because it moves resources from privately owned computers into the Internet "cloud." Platform as a Service (PaaS) is an outgrowth of Software as a Service (SaaS), a software distribution model in which applications are hosted by a vendor or service provider and made available to customers over the Internet.

With PaaS, operating system features can be changed and upgraded frequently. Geographically distributed development teams can work together on software development projects. Services can be obtained from diverse sources that cross international boundaries. Initial and ongoing costs can be reduced by the use of infrastructure services from a single vendor rather than maintaining multiple hardware facilities that often perform duplicate functions or suffer from incompatibility problems. Overall expenses can also be minimized by unification of programming development efforts.