Like millions of people around the globe, you sit down in front of your TV or open any of your devices and sign in to Netflix. Then, you select your movie or show and it plays seamlessly within seconds. Behind this smooth experience lies a complex web of cloud infrastructure. Netflix relies on Amazon Web Services (AWS) to store its content, run custom tools built on platform services, and deliver content through a smart, user-friendly interface. So, while you are watching your show or movie, you are unknowingly interacting with all three major layers of cloud computing: Infrastructure as a Service (IaaS), Platform as a Service (PaaS), and Software as a Service (SaaS).
Cloud computing has reshaped the way modern businesses operate, fuelling a global wave of digital transformation. Today, more than 90% of companies worldwide use cloud technologies, with expectations of reduced costs, greater scalability, and faster, more efficient service delivery. The trifecta of these key models in cloud computing – SaaS, PaaS, and IaaS – lies at the heart of this transformation. These distinct service models define the architecture of the digital age. In this blog, we discuss the constructs of SaaS vs. PaaS vs. IaaS, key differences between them, and how companies can leverage these models together to maximise benefits.
Software as a Service (SaaS) – In this model, ready-to-use applications are made accessible via the internet. These applications are managed by third-party vendors, which includes everything from infrastructure to data security. Users can access services such as email and customer relationship management (CRM), as well as collaboration or project management tools without installing or maintaining software on their local devices. Salesforce, often referred to as the poster child of SaaS, was one of the earliest adopters of the SaaS model. The company offers CRM software to over 150,000 companies globally, and boasts of a business model built entirely around cloud delivery, eliminating the need for on-premise deployment.1
Platform as a Service (PaaS) provides tools and frameworks primarily for developers to use when they need to build, test, and deploy applications. With PaaS, users manage their applications and data, while the service provider handles the operating system, servers, and storage. Typically, this model is beneficial for streamlining development processes without managing servers or storage. AWS Elastic Beanstalk, Google App Engine, Heroku, and OpenShift are examples of platforms in the PaaS model.
Infrastructure as a Service (IaaS) is the core foundation of cloud computing that underpins the other service models like PaaS and SaaS, which are built on top of this fundamental layer. It offers virtualised computing resources through the cloud. In this model, users have access to IT infrastructure such as virtual machines (VMs), storage, and networking over the cloud, and can use it with a pay-as-you-go option. With this service, users get the maximum control over their operating systems, runtime, and applications, but not the hardware.
Software as a Service (SaaS) offers simplicity and agility. Businesses get the advantage of being able to access powerful software applications such as email, CRM systems, or project management tools, without installing anything locally. Updates, maintenance, and security are managed by the provider, freeing up valuable resources. SaaS models allow easy scalability, where business can add or remove users instantly, adapting to changes on demand. For example, tools like Microsoft 365 or Zoom have become integral to operations across industries, allowing organisations of any size to operate with the same level of professional capabilities.
Platform as a Service (PaaS) benefits developers by providing a ready-made environment in which to build, test, and deploy applications. It eliminates the hassle of managing servers, operating systems, and middleware, thereby allowing teams to focus on coding and innovation. Thus, PaaS provides agility to the development cycles and simplifies collaboration. With PaaS platforms, developers can release updates quickly and securely. Overall, PaaS offers benefits of agility, high availability, scalability, while minimising technical roadblocks during the software development process.
Infrastructure as a Service (IaaS) delivers maximum control and flexibility. It enables businesses to run virtual machines, store massive amounts of data, and configure networks as per requirements, without the need for capital expenditure on physical hardware. Enterprises with specific compliance or performance requirements often rely on IaaS providers to scale infrastructure on demand, run legacy systems, or build hybrid cloud environments.
When combined, SaaS, PaaS, and IaaS create a highly versatile cloud ecosystem that caters to a wide range of business and technical needs. Whether it is accessing email via SaaS, building an app using PaaS, or hosting data centres on IaaS, each model offers unique advantages. Yet, while being presented as distinct models, they often coexist within a single solution stack.
Choosing the right model depends on several factors including organisational size, technical expertise, industry segment, business needs, and compliance requirements among others. For instance, an organisation can use all three in tandem: a SaaS solution for customer service, a PaaS environment for internal development, and IaaS for data storage and backups. Take the example of a tech company that is developing a health app. It will use IaaS to host the infrastructure, deploy the backend using PaaS services, and then offer its app to its customers through a web or mobile interface that operates like a SaaS solution.
For small businesses or startups, SaaS is often the most accessible. Requiring practically no technical setup, it allows the business to seamlessly and quickly access professional tools. If the organisation is large enough with in-house developers, it will benefit from PaaS. For organisations in industries such as finance or healthcare, security and control are important, hence they will choose an IaaS model. It is this seamless integration that gives cloud architecture its true power – enabling businesses to adapt, innovate, and scale on their own terms.