SaaS vs PaaS vs IaaS Explained: The Simple Guide

Three Letters, Three Very Different Things

SaaS, PaaS, and IaaS all describe cloud computing service models — but they answer very different questions about how much you manage yourself versus how much the provider handles for you. Understanding the difference matters whether you're choosing business tools or deciding how to deploy your own product.

The simplest way to remember it: IaaS gives you the building blocks, PaaS gives you the workshop, and SaaS gives you the finished product.

IaaS — Infrastructure as a Service

IaaS gives you raw computing infrastructure — virtual servers, storage, and networking — without any physical hardware to manage yourself. You still install the operating system, configure the environment, and manage everything that runs on top of it.

• What you manage: OS, runtime, applications, data, security configuration
• What the provider manages: Physical servers, networking hardware, data centers
• Examples: AWS EC2, Google Compute Engine, Microsoft Azure Virtual Machines, DigitalOcean Droplets

IaaS is the right choice when you need maximum control — custom server configurations, specific compliance requirements, or infrastructure that doesn't fit a standard platform's constraints.

PaaS — Platform as a Service

PaaS gives you a ready-to-use platform for building and deploying applications without managing servers or infrastructure at all. You focus purely on writing code — the provider handles the operating system, runtime, and scaling underneath it.

• What you manage: Your application code and data
• What the provider manages: Servers, OS, runtime, scaling, patching
• Examples: Vercel, Heroku, Render, Google App Engine, Railway

PaaS is ideal for developers who want to ship fast — push your code and the platform handles deployment, scaling, and infrastructure decisions automatically.

SaaS — Software as a Service

SaaS delivers fully finished software that you access directly, usually through a browser, with zero setup or maintenance on your end. You're not building anything — you're just using it.

• What you manage: Just your account and data usage
• What the provider manages: Literally everything else — servers, code, updates, security
• Examples: Gmail, Slack, Notion, Netflix, Salesforce, QuickBooks

SaaS is what most people use every day without thinking about it — ready-made tools that solve a specific problem the moment you sign up.

Side-by-Side Comparison

How They Fit Together

These three layers actually stack on top of each other. A SaaS product like Slack is very likely built and deployed on top of PaaS or IaaS infrastructure behind the scenes. PaaS platforms like Vercel run on top of IaaS providers like AWS. As a business, you'll often use all three at once for different purposes:

• SaaS for daily operations — Slack for chat, Notion for docs, QuickBooks for accounting
• PaaS for deploying your own product quickly — Vercel or Render hosting your web app
• IaaS for custom backend infrastructure at scale — AWS servers running your database and core services

Conclusion

SaaS, PaaS, and IaaS all answer the same underlying question — how much do you want to manage versus how much do you want handed to you — just at different layers of the stack. Use SaaS when you want a solved problem. Use PaaS when you want to build fast without touching infrastructure. Use IaaS when you need full control over how everything runs underneath. Most growing businesses end up using a mix of all three — and that's exactly how it's meant to work.