What Is SaaS? SaaS, PaaS, and IaaS Explained

by | Apr 18, 2024

The cloud computing age has brought with it critical acronyms that often seem confusing to anyone outside the realm of IT. For finance professionals navigating the mid-market, comprehending Software as a Service (SaaS), Platform as a Service (PaaS), Infrastructure as a Service (IaaS) – and now XaaS, isn’t just about keeping pace; it’s necessary to direct operational efficiencies and strategic financial management.

Amid the buzz of the tech world, distinguishing between SaaS, PaaS, and IaaS is critical—a misstep in comprehension could lead to misdirected investments, operational friction, or missed opportunities. Every finance and IT professional must recognize these models as fundamental components in their technology stack overhead costs, just as leases and other tangible assets are.

This blog will serve to break down the differences between the various cloud computing solutions, empowering you to make informed choices for your organization’s technology stack both financially and operationally.

Understanding SaaS

SaaS, at its core, transforms software from a product hosted in on-premise tangible servers into a service accessible over the internet. It’s the epitome of convenience, offering applications without the traditional hassles of installation and maintenance. Popular examples, such as Salesforce for customer relationship management (CRM) and Google Workspace for productivity, illustrate the broad spectrum of services SaaS can encapsulate. Typically, an end user such as an organization will pay a prepaid subscription fee to benefit from these services.

Advantages of SaaS

SaaS offers unparalleled accessibility and can swiftly scale with business demands. The COVID pandemic significantly increased the demand for SaaS applications as it drove millions of workers across all industries to work remotely. Working from home presented less of a challenge when all of your regular applications were accessible on the cloud. The user-centric approach means maintenance overhead is significantly reduced, and generally managed by the service provider. Furthermore, the subscription-based pricing model fosters predictability in expenditure, allowing for efficient financial planning and forecasting.

Potential downsides

Yet, SaaS comes with potential downsides both Finance and IT professionals should acknowledge.

  • Customization, while available to a certain extent, is often more restricted than with traditional software models, potentially constraining the industry or business solutions that distinct business needs may require.
  • Internet dependency also presents continuity risks, necessitating robust contingency plans to mitigate potential outages.
  • SaaS sprawl is a common challenge for organizations of any size, with the proliferation of software to solve problems across all areas of a business.
  • Shadow IT can also easily occur when departments and teams take advantage of the simplicity at which SaaS applications can be procured and tailored to their functions without consulting with IT.

Understanding PaaS

PaaS, like Salesforce Marketplace and NetSuite, empowers organizations to streamline development processes, offering a range of tools, middleware, and operating systems accessible over the internet. Developers leverage these platforms to rapidly create and deploy applications, focusing on innovation rather than infrastructure management. If SaaS is the applications we use in our day-to-day job functions, PaaS are the platforms developers use to build these applications rapidly without the complexity of building and maintaining the underlying infrastructure.

Advantages of PaaS

For finance professionals dipping their toes into software development, PaaS is a revelation. Streamlined processes from coding to deployment not only enhance speed but also deliver a unified and supportive toolkit for developers. The additional layer of abstraction from infrastructure intricacies affords a focus on innovation rather than IT management. Those cost savings afforded to software developers and tech companies are then passed down to us, the organizations who are ultimately the end users of software.

Potential downsides

Nonetheless, the deeper integration and reliance on PaaS platforms can breed concerns about lock-in, potentially limiting future technological and financial strategies. The complexity of integrating with existing infrastructures remains a consideration, requiring judicious planning and oversight to ensure synergies are achieved without compromise.

Understanding IaaS

Infrastructure as a Service (IaaS) is a cloud computing model that provides virtualized computing resources over the internet. Instead of maintaining physical hardware and infrastructure on-site, users can leverage IaaS to access and manage computing resources remotely. Key components of IaaS include virtual machines, storage, networking, and other fundamental computing resources. This model allows organizations to scale resources dynamically, paying only for what they use on a subscription or utility basis. Two great examples of IaaS are Amazon Web Services (AWS) and Microsoft Azure.

Advantages of IaaS

For starters, IaaS eliminates the need for upfront investments in hardware and infrastructure, reducing capital expenditures. Organizations that develop software can scale resources as needed, optimizing operational costs which then are passed down to the customers subscribing to the SaaS applications. IaaS offers global accessibility and near 100% uptime for the applications that drive our organizations while also putting the onus of security, maintenance, and compliance on the IaaS provider rather than the end user who neither download the applications nor host them on internal servers.

Potential downsides

While IaaS providers typically guarantee high levels of uptime, there can still be occasional outages or performance issues.

  • As a user of SaaS applications hosted on IaaS, any downtime or performance degradation experienced by the underlying infrastructure can directly impact your ability to access and use the software effectively.
  • However, migrating existing applications and data to another provider or back to an on-premise solution can be complex, time-consuming, and expensive.
  • While IaaS providers typically offer robust security measures, users of SaaS applications may still have concerns about the security and compliance of their data.
  • Users of SaaS applications hosted on IaaS are dependent on the IaaS provider chosen by the software vendor. If the software vendor’s chosen IaaS provider experiences issues or goes out of business, it could disrupt access to the SaaS application.

What about everything else that’s not SaaS, IaaS or PaaS?

There’s a name for that too and it’s called XaaS, which stands for “Anything as a Service” or “Everything as a Service.” SaaS, IaaS and PaaS are all different types of XaaS offerings. More broadly speaking, XaaS refers to services delivered over the internet, primarily focusing on software and occasionally extending to infrastructure and platforms. Examples include Data as a Service or AI as a Service to name a couple.

While hardware itself isn’t traditionally classified as XaaS, some hardware-related services, such as hardware leasing or equipment maintenance, can be offered as part of an XaaS model. These services may be bundled with software or platform offerings to provide a single service. Despite the advantages of XaaS, including increased flexibility and reduced IT overhead, it also presents challenges such as security, scalability, cost, and interoperability, similar to other cloud computing services.


Understanding the nuances of SaaS, PaaS, and IaaS, empowers finance and IT professionals to make informed decisions for their organization’s tech stack, considering both financial and operational perspectives. SaaS simplifies software accessibility, PaaS streamlines development processes, and IaaS provides virtualized computing resources, each offering unique advantages and potential downsides that must be carefully navigated. With the ever growing adoption of software within organizations, the synergy between the office of the CFO and CIO will only continue to deepen.


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