The main difference between IaaS and PaaS is how much of the technology your team must manage. Moving an application to the cloud changes those responsibilities; it does not remove them.
Reviewed 23 October 2026.
IaaS gives you control of virtual infrastructure
Infrastructure as a Service, or IaaS, provides computing resources such as virtual machines, storage and networking. Azure Virtual Machines is one example.
The provider manages the physical infrastructure. You still need to arrange administration of the operating system, applications, access and configuration. That work can sit with your own IT team, a managed provider or an agreed combination of the two.
PaaS provides a managed application platform
Platform as a Service, or PaaS, provides a platform for running applications without administering the underlying virtual machines and operating system yourself. Azure App Service is one example.
Your responsibilities still include the application you deploy, its configuration, identities and data. The exact boundary depends on the service. Check it before assuming a supplier handles a particular update or security control.
How SaaS fits into the decision
Software as a Service, or SaaS, provides a finished application, such as Microsoft 365. You use and configure the application rather than build its underlying platform.
For a business choosing a ready-made application, the SaaS product may be the main decision. IaaS and PaaS become more relevant when you need to host an existing system or develop and operate an application.
Compare responsibilities before comparing prices
| Area | IaaS | PaaS |
|---|---|---|
| Physical infrastructure | Cloud provider | Cloud provider |
| Underlying operating system | Your agreed IT owner | Cloud provider |
| Application and configuration | Your agreed IT owner | Shared duties to confirm |
| Data and user access | Your business retains responsibility | Your business retains responsibility |
Microsoft’s cloud shared responsibility guidance explains these boundaries in more detail.
Choose around the application and the people supporting it
Start with the application’s technical requirements and the support available from its vendor. Check compatibility, integrations, performance, access from your locations and how changes will be tested.
Then assign owners for updates, monitoring, incident response and recovery. If your internal team needs extra capacity, consider how co-managed IT support would fit those duties.
Compare the full operating cost, including licences, management time, connectivity, backup, recovery arrangements and the cost of leaving the service. A lower hosting price alone does not establish a lower overall cost.
Plan recovery before moving the workload
Agree which systems must return first after an outage and how you will test that they work. Check the service’s recovery features against your requirements and make separate backup and disaster recovery arrangements where needed.
Utility businesses can also review our IT support for utility businesses when planning changes around critical services.
Discuss the application, its dependencies and your support responsibilities with our team through CIS cloud services.
