IaaS vs SaaS vs PaaS: A guide to Azure cloud service types


Blue and green clouds representing three types of Azure cloud service types: IaaS, PaaS, and SaaS

It’s 2019, so we’ll assume you’ve heard of cloud computing by now.

Even so, if you’re not super tech-savvy, you might still be a little cloudy on terms like IaaS, PaaS, and SaaS, and the differences between them.

And that’s fine. This whole cloud thing is very new and can be pretty confusing with its many acronyms and jargon. But the fact is that cloud computing is the future, and the future is here. If you and your business want to stay productive and competitive, you’re going to need to hop aboard the cloud train.

If you’re thinking about implementing cloud computing in your organization, you’re going to want to know about these services. Worry not, we’re going to demystify “as a service” and explain how Microsoft Azure can help you take advantage of them.

As a Service: The basics

IaaS, PaaS, and SaaS are essentially the three main pillars of cloud computing. These easily confusable abbreviations stand for:

  • Infrastructure as a Service (IaaS)
  • Platform as a Service (PaaS)
  • Software as a Service (SaaS)

“As a service” simply means a facility, usually related to IT, computing, or telecommunications, that’s available to its users as a service, rather than something they install and operate themselves through their own hardware. These services are accessed through the internet.

For example, a few years ago if you wanted to be able to create and edit documents, you might have purchased Microsoft Word. This purchase probably entailed buying a disc containing the software, installing it on your computer. A one-time purchase, after handing over your cash you’d be able to use Word forever (this kind of software purchase is known as a perpetual license). If you wanted to update Word to get new features, you’d have to download the update and install it on your computer. That software would be run on, and therefore only accessible from, the computer that it was installed on.

Now, Word is available “as a service.” Rather than having to download Word and use it on a single device, customers can use a SaaS version that’s hosted on Microsoft’s internal servers. Instead of paying for the software outright, customers pay a subscription fee to access it; Word then becomes less of a product people purchase, and more of a service they pay to use.

The benefits of “as a service” models are enormous. Here are just a few:

Lower cost

You don’t have to have a big chunk of cash upfront to buy the software. Instead, you can pay a smaller price on a monthly or yearly basis. Not only does this make the software more accessible, but it also means that if you decide you don’t need it anymore, you can simply cancel the subscription without being lumbered with an expensive tool that you don’t use.

More flexible

If you have a piece of software installed on your home computer, that’s the only place you can use it. With a SaaS version, you just log in to a website from any device—whether that’s your laptop, your phone, your tablet, a public computer, your work computer, your mom’s computer… you get the idea—and you can use the software.

Always up to date

As it’s based on the vendor’s own servers, you’ll always be presented with the latest version of your “as a service” product, without you having to manually download and install updates.

Better features

Generally speaking, software vendors are focusing more on cloud versions of their products, so embracing SaaS means you get access to the best and newest features. Plus, because they’re powered by the cloud, SaaS products are more powerful and capable of much more than a traditional version (which can only do as much as your computer can process).

Less demanding on infrastructure

If your computer isn’t powerful or new enough to run certain software, you don’t have to miss out. SaaS software isn’t run from your machine, so as long as you can connect to the internet, you don’t need to buy or maintain hardware, which saves you time and money.

Table illustrating differences between saas, paas, and iaas

What is IaaS?

Before we go into what Infrastructure as a Service is, it’s worth taking a second to define exactly what we mean by infrastructure when it comes to computing.

Infrastructure is the digital scaffolding that supports a computer system; the really important back-end things like servers and storage, networks, security, and data centers. Traditionally, these aspects of computing would be the responsibility of an organization’s own IT department, housed and managed under its own roof.

IaaS gives businesses the option to have a vendor provide and manage these things on their end. This service enables companies to get rid of the hassle of having to operate infrastructure and hardware of their own.

Through IaaS, businesses can access the amount of computing, storage, and networking power they need over the internet from a third-party provider, giving them the freedom to access an IT environment that suits their needs, and can be scaled up or down as required without forking out for additional servers or hardware.

IaaS providers can deliver and manage services like firewalls, network connections, load balancers, data storage, and identity management. With these resources taken care of, businesses can take this infrastructure and build on it, installing operating systems, creating databases, and storing files.

What is PaaS?

If IaaS is at the bottom of the cloud computing pyramid, covering the fundamental infrastructure on which all other computing factors are built, then PaaS sits in the middle.

Customers can use PaaS to bolt cloud capabilities onto their own existing network. The PaaS model provides businesses with cloud components for certain software, offering a cloud-based framework on which developers can build and deploy custom applications.

Just as IaaS gives businesses the frameworks to build a computing environment that suits their needs, PaaS gives businesses the digital platform to develop and deploy their own apps and services, without the need to maintain server space, programming software, and security protocols internally.

The main difference between IaaS and PaaS is that with PaaS, the customer is consuming the core service needed for the own applications, and the “under the hood” management is left to the cloud vendor.

Using PaaS, businesses can create and develop services of their own on an existing platform, using tools that they can license from a third party vendor who’ll take care of all the updates and management of that platform. PaaS makes it faster, cheaper, and simpler for businesses to build their products and services, and scale their resources as needed without significant financial outlay.

In an era when consumers expect great experiences on mobile and on the web, being able to access platforms on which to create apps and services quickly and easily is essential; that’s a major reason why PaaS has become so popular.

Heroku, Salesforce, and Google App Engine are all common examples of PaaS; they provide a platform on which users can build and run their own software.

What is SaaS?

SaaS, or software as a service, is a model through which software is delivered via the internet, rather than being downloaded onto individual devices. The software is managed by a third-party vendor, and is typically accessed through an app or a web browser.

With SaaS, every aspect of the software’s hosting, setup, and maintenance is handled by its vendor. All you need to do to access it is log in to an app or browser, and use the software in the same way as you would a traditional desktop application installed on your own computer.

All of your data, files, and usage history is stored at the vendor’s end, within a multi-tenancy cloud; essentially a huge network of centrally maintained servers shared by all the software’s users. As a result, the software is accessible from anywhere, on any device, and data is always backed up to a centralized location—but your information can’t be seen or accessed by other software users.

Office 365, Google Drive, DropBox, Slack, MailChimp, and Netflix are all SaaS applications.

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Phew. Anything else I need to know about?

Infrastructure, platform, and software are the three titans of cloud computing, however, as the tech has advanced, more uses for the cloud have cropped up, meaning there are countless other “as a Service” models out there. And it’s likely that they’ll just keep coming (sorry). On the bright side, there are now so many service types that many in the IT community have started using the catch-all term XaaS; meaning anything as a service.

Here are some of the more common fringe service models you might come across:

DbaaS (Database as a Service)

This one is pretty self-explanatory. DbaaS are databases hosted on a vendor’s servers, where you can store and access structured data. One of the big advantages offered by DbaaS is that your data enjoys high availability, tight security, and is protected against loss. Employing DbaaS also means you don’t have to run your own servers to house all your data.

FaaS (Functions as a Service)

FaaS is essentially a simpler version of PaaS. Known as serverless architecture, FaaS is auto-scalable, and uses trigger events to run functions without having to worry about deployment or server resources.

AaaS (Analytics as a Service)

Also known as Insights as a Service, AaaS is any web-delivered platform that provides analytical capabilities, including big data management and visualization. AaaS platforms give companies access to tools like machine learning and AI on an on-demand basis, so they can enjoy cutting-edge analytical technology and avoid the heavy lifting of developing these tools themselves.

SECaaS (Security as a Service)

As our use of cloud technology increases, security becomes an ever-more pressing concern, and organizations large and small are targeted by cybercriminals every single day. Security as a service is enabling even companies who don’t have the resource to run the necessary security processes in-house to utilize enterprise-grade protocols by outsourcing their security management and monitoring.

VaaS (Virtualization as a Service)

Virtualization is a key component of modern cloud computing. VaaS delivers isolated virtual machines (VMs), hosted by the vendor, that can be customized to meet customer needs.

Not sure what a virtual machine is exactly? A virtual machine is a computer file, sometimes called an image, that acts like a real computer. VMs typically run in a window like traditional computer programs.

This computer-within-a-computer is boxed off from the rest of the system, so that any changes made or software run within the VM won’t “leak” into the host machine. VMs provide a sandbox environment in which developers can safely test things like beta releases, access virus-infected data, build system backups, and run applications on operating systems they may not be naturally compatible with, without the risk of damage to the wider system.

Several VMs can be run simultaneously on the same machine, and each VM has its own virtual hardware, including CPUs, memory, hard drives, network interfaces, and other devices. The virtual hardware can be mapped to the physical hardware, cutting costs by reducing reliance on actual hardware systems and their associated maintenance costs.

Is Azure IaaS or PaaS?

Azure offers all three of the core service models we’ve looked at, so, depending on which of Azure’s many services you opt for, you can take advantage of IaaS, PaaS, and SaaS on Microsoft’s cloud platform.

Now we know what all these service models are and what they do, it’s time to find out how Microsoft Azure can help you can utilize them in your business.

IaaS on Azure

Azure’s IaaS offering lets customers outsource all their network and computing needs to Microsoft, removing all infrastructure from the customer’s own servers and basing it all at Microsoft’s end. All infrastructure is managed on the customer’s behalf, leaving you to purchase, install, configure, and operate the software that runs on it, such as operating systems, apps, and middleware.

Azure can provide a virtual data center, complete with security features, through which businesses can host websites, store and backup data, develop and test environments, build web apps, and run high-performance computing.

Azure offers a massive range of IaaS facilities depending on the needs of your business, from compute and networking to security and storage, including Container Service and Virtual Machines. Find out more about individual services here.

PaaS on Azure

If you prefer to go down the PaaS route on Azure, there’s no shortage of services to help you implement a cloud-powered development platform. Through PaaS services like app Services, Azure Search, and Azure CDN, Azure offers everything companies need to deliver cloud applications on a pay-as-you-go basis, from the smallest web apps to enterprise-level software.

Azure’s PaaS offerings give developers total control over their application, allowing them the freedom to work on building, safe in the knowledge that things like OS patches or load balancing will just work. With services like Azure Functions, businesses can take advantage of PaaS power without having to worry about server configuration or scaling, which is automatic.

SaaS on Azure

Azure can be used both to host apps you’ve created yourself, and to access other Microsoft SaaS services. Cloud-based Microsoft products like Dynamics 365, Outlook, and Office 365 are all built and hosted on Azure.

Using Azure as a foundation for your SaaS apps lets you take advantage of powerful technology and intelligent tools like analytics and machine learning.

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