Infrastructure & Operations › Cloud Computing
IaaS, PaaS, SaaS
How much of the stack the provider manages for you.
Also known as: IaaS, PaaS, SaaS, cloud service models
The three labels describe how much of the technology stack the provider runs for you. The more they manage, the less you control and the less you maintain.
| Layer | IaaS (Infrastructure) | PaaS (Platform) | SaaS (Software) |
|---|---|---|---|
| Your application and data | You | You | Provider |
| Runtime, libraries | You | Provider | Provider |
| Operating system | You | Provider | Provider |
| Virtualization, servers, network | Provider | Provider | Provider |
Examples
- IaaS: you rent raw building blocks such as virtual machines, disks and networks. You install and patch everything above the hardware. Example: a plain EC2 instance.
- PaaS: you hand over your code, and the platform runs it, scales it and handles the OS. Examples: Heroku-style platforms, App Engine, Azure App Service. See PaaS platforms.
- SaaS: you use finished software through a browser or API. Examples: Gmail, Slack, GitHub.
Serverless functions and managed databases sit around the PaaS end: you write the logic, the provider handles the machines.
How to think about the trade
More managed means less operational work and faster start-up, but less control over the environment, sometimes higher prices at scale, and more lock-in. More control means you also own the patching, scaling and 3 a.m. pages.
The boundaries are fuzzy and vendors use the labels loosely, so judge a service by one question: what exactly do I still have to maintain? See also the shared responsibility model.