SaaS, PaaS and IaaS: An overview

The cloud has certainly been a disruptive technology and it has radically changed how companies of all sizes do business. The bulk of businesses have moved to the cloud in some way, and for those that have not the prospect of cost savings through reduced in-house IT requirements and other benefits certainly puts cloud transition at the top of any corporate to do list.

While most companies now often benefit from utilizing cloud-based Software-as-a-Service (SaaS) options, areas like Platform-as-a-Service (PaaS) and Infrastructure-as-a-Service (IaaS) might remain something of a mystery.

What follows then is an overview of SaaS, PaaS and IaaS and a few insights regarding their relative benefits.


SaaS is a straightforward model that is easy for even the least technically minded executive to recognize the benefits of. Microsoft’s Office 365 is probably one of the most immediate examples of how SaaS benefits almost every company.

In the early days Microsoft’s ‘Office’ software (Word, Excel, Outlook, etc. – the ubiquitous software for a modern office) was purchased directly from the company on CDs and installed manually onto a business’ PCs.

This meant having staff available to make the installations and to provide troubleshooting services when software issues arose.

The same member of staff would be responsible for adding patches and updates. When the latest version of the software arrived, that meant updating several PCs, and again, you needed someone to do this. These days it is easier – the software is in cloud.

With Office 365, Microsoft is responsible for hosting the software rather than it being on disks. It is easily downloaded onto a computer and the delivery of updates and patch installations is managed by Microsoft themselves. When the latest version of the software becomes available, again, there is automatic installation saving time and money.

Aside from Office 365 there are numerous other examples of SaaS options a business executive might be familiar with.


PaaS is designed to address another set of problems. Not all business issues are solved by ‘one size fits all software like Office 365.

Businesses often have unique and specific business requirements and to address them they need to create unique applications that perform specific functions.

In the past, this of course meant having a programmer and setting up an environment where software coding and testing could take place. This usually required a server and beyond that, companies needed to load servers with expensive software which a programmer would use to do his/her job.

These days everything can be done in the cloud.

Most apps now run in a cloud environment and a PaaS provider provides an infrastructure where cloud-based apps can be created. PaaS providers provide the tools required to create the software applications that will be hosted in the cloud (whether it is an in-house private cloud, in a public cloud like AWS or Azure, of a ‘hybrid’ combination of the two).

PaaS literally offers everything you need to in the cloud and it is all managed by a third party – in many instances this can reduce 80% or more of the cost.

However, there are several reasons why companies might ditch their current development infrastructure in favor of PaaS.


Most modern companies have IT requirements and depending on their need this could include having a dedicated data center and covering the massive costs inherent in such an undertaking. IaaS provides an option to move such infrastructure to the cloud.

IaaS offers companies a ‘do-it-yourself’ approach to managing data center infrastructure and avoids the excessive hardware and software costs required to setup an effective infrastructure. In addition, payment for IaaS is based on usage.

It offers a utility approach, so in the same way you only pay for the electricity you use in your office, you only pay for the IT infrastructure you use.

Rather than rent server and infrastructure capacity you are not going to use just in case you need it, IaaS automatically (or on request) adds any additional resources needed and removes them when they are no longer required.

If you bought your own hardware for your IT infrastructure, you’d be responsible for upkeep – software, operating systems, etc., and this is how IaaS and PaaS differ. With IaaS you just acquire the infrastructure and you maintain it as your own.

Providers often offer additional services to differentiate their offerings, but at its core, you get infrastructure in the cloud and manage it yourself.

You can replace your company’s entire physical infrastructure, or in a hybrid fashion, just part of it. Whatever is the approach, as with PaaS, IaaS is scalable and automatically manages the resources your company needs.

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