Definition
IaaS, Infrastructure as a Service, is the most basic layer of cloud computing: a provider rents you virtual machines, storage, networks and related building blocks on demand, billed by the hour or second. You decide what runs on them and you manage the operating system, software and configuration. The provider owns the physical data centre, the hardware, the power and the network connections. It is the cloud equivalent of renting an empty, fully serviced building.
In a company, IaaS is what your engineering team means by "our AWS account" or "our Google Cloud project". The three large providers, Amazon Web Services, Microsoft Azure and Google Cloud, dominate the market, with regional and specialised players alongside them. IaaS gives maximum control and the lowest unit cost of the cloud layers, but it requires people who know how to configure, secure and monitor infrastructure, which is a real ongoing cost.
A misconception is that IaaS is just "someone else's computer" and therefore no different from a rented server. The difference is elasticity and automation: you can create 100 machines with a script, run them for an hour and delete them. In 2026 the IaaS market is heavily shaped by AI demand, with providers competing on GPU (Graphics Processing Unit) availability and pricing, and with a growing tier of specialised GPU clouds serving companies that train or run AI models.
In practice
A company processing month-end reports spins up 50 machines for four hours on the last day of each month and pays only for those hours. On dedicated hardware the same peak would have required owning 50 machines that sit idle the rest of the time.
Why it matters
IaaS turns capacity into a variable cost, which is a strategic advantage for any company whose demand is uneven. It also means an unmonitored account can burn cash fast, so someone should own the cloud bill like they own payroll.
Frequently asked questions
- What are examples of IaaS?
- Amazon Web Services (EC2, S3), Microsoft Azure Virtual Machines, Google Compute Engine, and providers such as Oracle Cloud, DigitalOcean, Hetzner and OVHcloud. Specialised GPU clouds that rent hardware for AI training and inference are also IaaS.
- Is IaaS cheaper than owning servers?
- It is cheaper when your usage varies, when you are starting out, or when you value not having a team run hardware. For large, steady, predictable workloads, owning servers can cost less over several years. Most companies land on a mix, and the deciding factor is how well they manage utilisation.