Infrastructure as a Service (IaaS)

A form of cloud computing that provides virtualized computing resources over the internet.

Infrastructure as a Service (IaaS) is a cloud computing model that provides virtualized computing resources over the internet on a pay-as-you-go basis. IaaS providers supply virtual machines, storage, networking, and other fundamental computing resources, while customers manage the operating system, middleware, runtime, and applications.

Major IaaS providers include Amazon Web Services (EC2), Microsoft Azure (Virtual Machines), and Google Cloud Platform (Compute Engine). IaaS offers flexibility and control similar to managing physical hardware but eliminates the capital expense and operational burden of maintaining data centers. Resources can be provisioned and scaled programmatically through APIs.

IaaS sits at the base of the cloud computing stack, below PaaS and SaaS. Compared to serverless computing, IaaS requires more operational responsibility -- teams must patch operating systems, manage scaling, and handle capacity planning. Many organizations use IaaS to host API backends and databases, while placing a serverless API gateway in front to handle routing, authentication, and traffic management without the operational overhead of managing the gateway infrastructure itself.