Platform-as-a-Service (PaaS) is a category of cloud computing that supplies an on-demand environment for software development over the Internet. Cloud providers (such as Amazon, Google or Microsoft) deliver the hardware and software tools needed for application development to their subscribers. The PaaS provider hosts the hardware and software on its own infrastructure, allowing subscribers to develop and run new applications without buying additional hardware and software. Like Infrastructure-as-a-Service (IaaS), PaaS provides servers, storage and networking, then adds middleware, development tools, business intelligence services, database management systems and other services. PaaS can support the complete web application lifecycle, from building and testing to deploying, managing and updating applications. Typically, PaaS supplements and does not replace an organization’s IT infrastructure. PaaS providers may charge subscribers for services on a per-use basis or a monthly flat fee.
Businesses of all sizes rely on PaaS for application hosting, Java development, compute and storage infrastructure, and key services such as text editing, version management, compiling and testing. PaaS enables IT departments to focus on creating and running new applications, rather than installing and maintaining the underlying infrastructure on premises. Multinational enterprises use PaaS to allow development teams to collaborate and work together regardless of their physical location.
PaaS providers usually include cloud features such as scalability, high-availability and multi-tenant capability in the development framework, reducing the coding time for application developers. Additional services PaaS providers may offer are data analytics, workflow, directory, security and scheduling. The risks associated with using PaaS include service availability, provider lock-in, and control over changes in programming languages or development tools. Private and hybrid PaaS environments can reduce these risks. Cloud Foundry is an open source PaaS that is not tied to a particular cloud provider.