IaaS is a form of cloud computing model that provides self-service models for accessing, monitoring, and managing remote datacenter infrastructures, such as compute (virtualized or bare metal), storage, networking, and networking services (e.g. firewalls).Instead of having to purchase hardware outright, users can purchase IaaS based on consumption, similar to electricity or other utility billing.

IaaS is one of three main categories of cloud computing services, alongside Software as a Service (SaaS) and Platform as a Service (PaaS). 

IaaS Examples: Amazon Web Services (AWS), Microsoft Azure, Google Compute Engine (GCE), Jelastic