Cloud computing basics: IaaS, PaaS and SaaS without the jargon

At its simplest, cloud computing means renting computing resources over the internet instead of buying and running your own servers. You pay for what you use, and you can scale up or down on demand. Most cloud services fall into three models, usually distinguished by how much the provider manages for you.

Infrastructure as a Service (IaaS)

IaaS provides the raw building blocks — virtual servers, storage, and networking — that you configure yourself. It is the most flexible and the most hands-on: you manage the operating system and everything above it, while the provider runs the physical hardware. Renting a virtual machine to host an application is a classic example.

Platform as a Service (PaaS)

PaaS goes a step further and manages the underlying platform for you — the operating system, runtime, and scaling — so you can focus on your code. You deploy an application and the platform handles the servers behind it. This trades some control for a lot less operational work, which is why many development teams favor it.

Software as a Service (SaaS)

SaaS is the model most people use every day, often without thinking about it: fully built software delivered through a browser. Email, document editors, and customer-management tools that you simply log into are all SaaS. The provider runs everything; you just use the application.

Why the model matters

The practical difference is how much responsibility you keep versus hand off. IaaS gives maximum control and maximum operational burden; SaaS gives minimum control and minimum burden; PaaS sits in between. Many organizations mix all three.

For a business, the appeal is the same across models: turning large upfront technology purchases into flexible, pay-as-you-go operating costs, and being able to grow capacity in minutes rather than months. Understanding which layer you are buying is the first step to choosing well.