What is the difference between IaaS, PaaS, and SaaS?

Question

Accepted Answer

**IaaS** — infrastructure. **PaaS** — platform. **SaaS** — software.

**IaaS (Infrastructure as a Service):**
- Virtual machines, storage.
- You manage: OS, apps.
- Provider manages: hardware.
- AWS EC2, Azure VMs.

```
IaaS:
You manage: OS, Runtime, Apps, Data
Provider manages: Virtualization, Servers, Storage, Network
(Most control)
```

**PaaS (Platform as a Service):**
- Development platform.
- You manage: apps, data.
- Provider manages: OS, runtime.
- Heroku, Google App Engine.

```
PaaS:
You manage: Apps, Data
Provider manages: OS, Runtime, Virtualization, Servers
(Less control, more convenience)
```

**SaaS (Software as a Service):**
- Ready-to-use software.
- You manage: nothing.
- Provider manages: everything.
- Gmail, Salesforce.

```
SaaS:
You manage: Nothing (just use it)
Provider manages: Everything
(Least control, most convenience)
```

**Key differences:**
- **IaaS** — most control.
- **PaaS** — balanced.
- **SaaS** — least control.

Systems Analyst: What is the difference between IaaS, PaaS, and SaaS?