Stop 01 · Cloud Computing FoundationsTopics · 3/9

IaaS vs PaaS vs SaaS

In short

Every cloud service sits somewhere on a scale from 'here's a bare machine, good luck' to 'just log in and use it'. Placing services on that scale tells you what work stays with you.

Infrastructure as a Service gives you raw compute/storage/networking, Platform as a Service manages the runtime so you just deploy code, and Software as a Service is a fully finished product you simply use.

The blob character chooses between raw vegetables with a stove, a steel tiffin and a restaurant thali.

Think of it like this

Cook, tiffin or restaurant

Buying vegetables and cooking is IaaS: you get the kitchen, you do everything. A tiffin service is PaaS: food arrives, you just add pickle and serve. A restaurant thali is SaaS: sit, eat, pay. Same dinner, different effort.

Watch it happen

What you still manage

App

you

Data

Runtime

Virtual machine

Network

Hardware

1/4On-premise, every layer from hardware to app is your job.

The big ideas

What you need to know

IaaS: raw building blocks

Virtual machines, disks and networks. Most control, most work. Examples: EC2, Compute Engine, Azure VMs.

PaaS: bring your code

You push code and the platform handles servers, OS and scaling. Examples: App Engine, Azure App Service, Heroku.

SaaS: finished product

Ready software you log into. Examples: Google Workspace, Salesforce, Zoom. You configure it, you don't run it.

Control vs effort

Moving from IaaS to SaaS, you give up control and get back time. Pick the level your team can actually handle.

Save yourself the pain

Common mistakes

Oops

Thinking SaaS means you have no security work at all.

Do this instead

You still own who has access, strong passwords, MFA and what data you put in.

Oops

Choosing IaaS for a simple website because it feels more 'real'.

Do this instead

If a PaaS can run it, you skip OS patching and server babysitting. Use IaaS when you need that control.

Your mission

Sort 10 services

~15 min

Quick check

Your team pushes code and the service handles servers, OS updates and scaling. What model is this?

Go deeper

1Classify 5 real cloud products you know into IaaS, PaaS, or SaaS.
2Learn how much operational responsibility shifts to the provider as you move from IaaS to SaaS.
3Understand this roadmap focuses primarily on IaaS and PaaS-level skills.