Azure Fundamentals: IaaS (Infrastructure as a service) vs SaaS (Software as a service) vs PaaS ( Platform as a service)
| IaaS | PaaS | SaaS | |
| Upfront costs | No Upfront costs Users pay only for what they consume. | No Upfront costs Users pay only for what they consume. | No Upfront costs Users pay only for subscriptions. |
| User ownership | User is resposible for software, operating systems, middleware, data and applications. | User is responsible for data and applications | Users just use the application software; they are not responsible for any maintenance or management of that software. |
| Cloud provider ownership | Hardwares, network etc. | Cloud providers are typically responsible for everything except Data & application | Cloud providers are typically responsible for everything including Data & application |
| Commonly used scenarios | Storage, backup, and recovery/Test and development | Azure Logic Apps | D365 Online/Skype |