Platform as a Service (PaaS) is a complete cloud development and deployment environment, with capabilities to deliver everything from simple cloud-based applications to sophisticated cloud-enabled business applications. Like IaaS, PaaS includes infrastructure (servers, storage, and networks), but it also includes middleware, development tools, business intelligence (BI) services, database management systems, and so on.
PaaS is designed to support the entire lifecycle of web applications: build, test, deploy, manage, and update. PaaS avoids the expense and complexity of purchasing and managing software licenses, the underlying application infrastructure and middleware, container orchestrators such as Kubernetes, or development tools and other resources. You manage the applications and services that you develop, and the cloud service provider typically manages everything else.