Stands for "Infrastructure as a Service."
Infrastructure as a Service is a type of cloud computing service that provides servers, data storage, virtual machines, and network connections as an on-demand service. Customers do not need to run their own data center or computer hardware; the IaaS provider handles all of the hardware maintenance and network connectivity, allowing the customer to focus entirely on the software they want to run.
IaaS is similar to other "as a Service" cloud computing products that offer managed server hosting services. IaaS provides only the managed hardware and network connection, leaving all software decisions and responsibilities to the customer. Other cloud products, like Platform as a Service (PaaS) and Software as a Service (SaaS), manage both the hardware infrastructure and the software platforms running on the hardware. IaaS customers handle their software installation, configuration, and updates. Allowing that much flexibility for software makes these services popular for software testing and development, web app and website servers, and high-powered computing and data analysis.
Like other cloud services, IaaS offers more flexibility than a company running its own data center. While a large enterprise can afford to build a data center, IaaS products are significantly cheaper for small and medium businesses to start using. Cloud services are scalable, allowing the customer to add computing or storage capacity when needed and then scale back later. Cloud data centers can also be placed around the world, offering redundancy and traffic balancing for the client.