Platform as a Service (PaaS) is a cloud computing service which provides application hosting, deployment and management tools. This typically includes hardware, operating systems, storage and network capacity.
You’re probably already familiar with the Software as a Service (SaaS) model. PaaS is an outgrowth of that. With SaaS, customers essentially rent access to a software application that is not hosted on their own equipment and is instead accessed over the Internet, in the cloud.
PaaS extends the SaaS model to improve the speed and cost of application development and delivery. PaaS lets you rent all the infrastructure you need to develop and run your own applications in the cloud.