Saas, PaaS, and IaaS: Understanding the Three Cloud Computing Service Models

SaaS, PaaS, CSB, CRM, MCM, and HPC… The rapidly expanding world of cloud computing is rife with cryptic acronyms and abbreviations. ‘Saas’, ‘PaaS’, and ‘IaaS’ are three of the most commonly used acronyms in the cloud sector, and for good reason. These three terms distinguish between the primary cloud computing service models: ‘Software as a Service’, ‘Platform as a Service’, and ‘Infrastructure as a Service’. Since cloud computing can fulfill virtually any IT need imaginable (and often in many different ways), these classifications are necessary to indicate the role that a particular cloud service fulfills, and how that service accomplishes its role. In other words, SaaS, PaaS, and IaaS are the three main paradigms of cloud computing.

IaaS (Infrastructure as a Service)

IaaS is the lowest-level cloud service paradigm and arguably the most important. With IaaS, pre-configured hardware resources are provided to users through a virtual interface. Unlike PaaS and SaaS, IaaS doesn’t include applications or even an operating system (implementing all of that is left up to the customer), it simply enables access to the infrastructure needed to power or support that software. IaaS can provide extra storage for corporate data backups, network bandwidth for a company website server, or it can even enable access to high power computing which was previously only accessible to those with supercomputers. Popular IaaS offerings like Amazon EC2, IBM SoftLayer, and Google’s Compute Engine (GCE) are silently powering a huge portion of the backbone of the internet, whether users realize it or not.

PaaS (Platform as a Service)

Gartner defines PaaS as a cloud service model where the cloud is used to deliver a platform to users from which they can develop, initialize and manage applications. PaaS offerings typically include a base operating system and a suite of applications and development tools. PaaS eliminates the need for organizations to build and maintain the infrastructure traditionally used to develop applications. PaaS is sometimes called ‘middleware’, referring to how it conceptually sits somewhere between SaaS and IaaS. Platform’s like Google’s App Engine, IBM BlueMix, and Apache’s Stratos are popular PaaS products which are helping to streamline and democratize software development.

SaaS (Software as a Service)

Sometimes referred to as ‘on-demand software’, SaaS is a software licensing and delivery model where a fully functional and complete software product is delivered to users over the web on a subscription basis. SaaS offerings are typically accessed by end users through a web browser (making the user’s operating system largely irrelevant) and can be billed based on consumption or, more simply, with a flat monthly charge. SaaS offerings are the most widely visible of all the cloud computing service models. In fact, many users might be using SaaS products without even realizing it. Popular products like Office365 and Salesforce have thrust SaaS offerings to the forefront of the workplace and are used by thousands of businesses every day.


Cloud computing has revolutionized the way IT departments manage and deploy infrastructure. Whether its SaaS, PaaS, or IaaS, there is a suitable cloud service to fulfill virtually any IT need imaginable. DoubleHorn is dedicated to one enduring idea: Improving the world-changing power of Clouds. We’ll continue to advocate for organizations who demand better prices, better coverage, better performance, better service, and Better Clouds. Reserve a complimentary cloud consultation today by contacting us at or 855-61-VOICE (86423) to learn more.

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Watch our upcoming webinar on July 25th at 2:00 pm SaaS, PaaS, and IaaS: Breaking Down The Three Cloud Computing Service Models
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