What is Platform as a Service (PaaS)?

PaaS, or Platform-as-a-Service, is a category of cloud computing services that provides a platform allowing customers to develop, run, and manage applications without the complexity of building and maintaining the infrastructure typically associated with developing and launching an app.

PaaS can be thought of as a layer on top of IaaS (Infrastructure as a Service), and it typically includes infrastructure — servers, storage, and networking — but also middleware, development tools, business intelligence (BI) services, database management systems, and more. PaaS is designed to support the complete web application lifecycle: building, testing, deploying, managing, and updating.

The PaaS model enables developers to create applications using built-in software components. Cloud features such as scalability, high availability, and multi-tenant capability are often included, so developers can focus on the application itself without having to worry about maintaining operating systems, software updates, storage, or infrastructure.

PaaS allows businesses to design and create applications that are built into the PaaS with special software components. These applications, sometimes called "middleware," are scalable and highly available as a service.

Some examples of PaaS include Microsoft Azure, Google App Engine, IBM Cloud, and Salesforce's Heroku. Each provides a different level of flexibility, control, and management, so choosing the right PaaS provider depends on the business needs, technical requirements, and desired level of control in application development and management.