Next, we have PaaS (or a Platform-as-a-Service) that provides cloud platforms and runtime environments for developing, testing and managing applications. It consists of a programming language execution environment, an operating system, a web server and a database. This service model enables users (who are mainly developers) to deploy applications without the need to acquire, manage and maintain the related architecture. If your organization needs a platform for creating software applications, PaaS is a model for you. Platform-as-a-Service only requires you to take care of the applications and the data; the rest of the components like runtime, middleware, operating systems, servers, storage and others, are handled by the cloud service providers. Some of the common Platforms-as-a-Service are Amazon Web Service, Google App engine, Windows Azure and Heroku.