Look, if you’ve spent more than five minutes in a tech meeting lately, you’ve definitely heard the acronyms. But understanding PaaS vs SaaS vs IaaS is about more than just passing a certification exam. It’s about knowing exactly what you’re responsible for when an app goes down at 2 AM.
I’ve seen plenty of teams get this wrong. They try to build a custom database cluster on raw hardware when they should’ve just used a managed service. Or they buy a subscription to a tool that doesn’t let them customize a single line of code. So, let’s break down the differences between PaaS vs SaaS vs IaaS in a way that actually makes sense for your daily work.
PaaS vs SaaS vs IaaS: Breaking Down the Layers
The easiest way to think about these models is by looking at how much work you’re outsourcing to someone else. It’s a sliding scale of control. On one end, you’re building the whole house; on the other, you’re just renting a room and expecting the towels to be clean.
IaaS: Infrastructure as a Service
This is the “raw” version of the cloud. When you use IaaS, you’re basically renting a server in someone else’s data center. You get the CPU, the storage, and the networking, but the rest is on you. You have to install the operating system, set up the security patches, and manage the middleware.
I’ve worked on projects where we needed total control over the kernel because of some ancient legacy software. In those cases, IaaS is a lifesaver. But for most modern apps? It’s often more overhead than a small team can handle. If you want a deeper look at the nuts and bolts, check out this IaaS explained guide.
Examples: AWS (EC2), Google Compute Engine, Microsoft Azure VMs
PaaS: Platform as a Service
Now we’re getting into developer territory. With PaaS, you don’t care about the server or the OS. The provider gives you a “platform” where you just push your code and it runs. They handle the scaling, the runtime, and the database management. This is where the Salesforce Platform lives.
Here’s the thing: PaaS is all about speed. You aren’t wasting weeks configuring load balancers. You’re writing Apex or Node.js and hitting “deploy.” If you’re wondering what is Platform as a Service for a developer specifically, it’s basically the freedom to ignore the plumbing and focus on the logic.
Examples: Salesforce Platform, Heroku, Google App Engine
SaaS: Software as a Service
This is the most common model. You’re just using the software. You don’t manage the code, the servers, or the updates. You just log in and go. Salesforce CRM is the classic example here. You don’t “build” the lead object from scratch in a database; you just configure it.
But don’t mistake “easy” for “limited.” Modern SaaS tools allow for a ton of configuration. One thing that trips people up is thinking they can’t customize SaaS. You can, but you’re working within the guardrails the provider set. If you want to know more, I’ve written about what is SaaS in the context of the Salesforce ecosystem.
Examples: Salesforce, Slack, Google Workspace, Microsoft 365
Real-World Scenarios for PaaS vs SaaS vs IaaS
So how do you actually pick? In my experience, it usually comes down to your team’s skills and your deadline. If you have a team of elite DevOps engineers and a very specific security requirement, IaaS might be the play. But honestly? Most of the time, that’s overkill.
Pro Tip: Before you commit to IaaS, ask yourself if you really want to be responsible for OS security patches at 3 AM. If the answer is no, look at PaaS or SaaS instead.
Here is a quick breakdown of when to use each model:
- Use IaaS if you need to run specific legacy apps or need full control over the tech stack.
- Use PaaS if you’re building custom apps and want to get to market fast without managing hardware.
- Use SaaS for standard business functions like CRM, email, or collaboration where you don’t need to reinvent the wheel.
The Responsibility Matrix
I like to use a simple table to show who does what. It helps clear up the confusion during architectural reviews.
| Feature | IaaS | PaaS | SaaS |
|---|---|---|---|
| Networking / Storage | Provider | Provider | Provider |
| Operating System | You | Provider | Provider |
| Runtime / Middleware | You | Provider | Provider |
| Application Code | You | You | Provider |
| Data / Config | You | You | You |
Key Takeaways
- IaaS gives you the most control but requires the most maintenance.
- PaaS is the sweet spot for developers who want to build fast.
- SaaS is the go-to for ready-to-use solutions with zero infrastructure work.
- The choice between PaaS vs SaaS vs IaaS depends on your specific business goals and technical capacity.
Making the Right Choice
At the end of the day, there isn’t a “best” model. I’ve worked on projects that used all three at once. We used SaaS for our CRM, PaaS for a custom customer portal, and IaaS for a specialized data processing engine. It’s all about using the right tool for the job.
Start by looking at your requirements. If you can solve the problem with a SaaS configuration, do it. It’s the least amount of work. If you need a custom app, go PaaS. Only go down to IaaS if you have a very specific reason to manage the “metal” yourself. Keep it simple, and your future self will thank you when you aren’t stuck fixing server errors on a holiday.