Infrastructure as a Service (IaaS) is a cloud computing model in which a third-party provider delivers infrastructure services, such as computing, networking, storage, and more, over the internet. These services are delivered on a pay-per-use basis, meaning that customers only pay for the resources they consume.

IaaS is one of the three main categories of cloud computing services, along with Software as a Service (SaaS) and Platform as a Service (PaaS). It is the most basic and foundational level of cloud computing, providing just the underlying infrastructure without any additional software or platform services.

One of the main benefits of IaaS is its flexibility. It allows customers to customize their infrastructure to meet the specific needs of their applications, including choosing the operating system, database, middleware, and other components. It also provides a high degree of scalability, allowing customers to easily increase or decrease their resources as needed.

IaaS also offers a number of cost benefits compared to traditional on-premises infrastructure. It allows customers to pay only for the resources they consume, rather than having to make upfront investments in hardware and infrastructure. It also provides a level of agility and speed, allowing customers to quickly provision and deploy new resources as needed.

IaaS is a powerful and flexible way to access and use infrastructure resources in the cloud. It is widely used by organizations of all sizes across a variety of industries, and is one of the foundations of modern cloud computing.