Cloud Computing: SaaS, IaaS, and PaaS

Alan Cooke, Researcher at TrustRadius
Alan Cooke
December 17, 2019
IT & Development

Cloud Computing: SaaS, IaaS, and PaaS

Cloud computing defines the delivery of computing services over the Internet. To be more precise, cloud computing platforms provide access to a shared pool of configurable computing resources such as networks, servers, storage, applications and other services that can be rapidly provisioned over the Internet. 

Most technology buyers are familiar with the most well-known cloud computing model, Software-as-a-Service (SaaS). The other two are Platform-as-a-Service (PaaS) and Infrastructure-as-a-Service (IaaS). 

How are these different cloud computing models different? 


Applications running in the cloud are offered to application consumers or end-users as a service over the Internet. The SaaS provider handles all the infrastructure and upgrades Consumers of the software service typically access it via a web browser and pay a monthly or annual subscription. This pricing model provides lower upfront costs to users and a reliable income stream to vendors. 


PaaS is a development and deployment environment in the cloud that makes coding and deploying applications much more efficient for developers. It is essentially a platform for building scalable software delivered over the web with modest up-front investment. 

PaaS is designed to release application developers from the complexity of provisioning, configuring, managing, and updating hardware resources by providing the operational components underlying application development. These include operating systems, databases, container orchestration, middleware, and BI as cloud-enabled services. Developers of business applications don’t have to worry about scalability and security issues and are free to focus on developing applications. 


IaaS, unlike its close cousin PaaS, is not aimed at application developers, but rather at IT professionals. An IaaS is a service providing the most fundamental layer of cloud services including compute, storage, and networking services. IaaS scales infrastructure components up and down with demand and avoids the complexity and expense of having to manage physical servers and other datacenter infrastructure. IaaS platforms allow users to install and configure operating systems, middleware and applications. 

Do I need IaaS or PaaS?

It is important for buyers to clearly understand the differences between these three elements of cloud computing. Particularly, the significant differences between IaaS and PaaS. The decision to purchase either a PaaS or an IaaS platform depends on what the organization needs most. A PaaS platform can be very useful for earlier stage companies that urgently need to build out the first iteration of a product. PaaS capabilities can greatly speed up the pace of development which can be crucially important for emerging companies. 

On the other hand, companies are increasingly moving away from the significant overhead of building an in-house data center. Businesses that adopt IaaS allow a third-party vendor to deliver their IT resources, which effectively shifts all the complexity to a 3rd-party vendor. An IaaS platform provides several significant advantages to businesses. Not least are the cost model whereby up-front expense is exchanged for a subscription model with predictable monthly or annual payments. IaaS also offers unmatched scalability. Scaling up or down operations is a much simpler process than it would be in an in-house datacenter. IaaS vendors also offer greater reliability than is possible with an in-house data center because they offer services through a multiplicity of servers and data centers, making it much easier to recover in the event of unscheduled downtime.

A good way to understand the value provided by IaaS and PaaS platforms, and to help choose the right vendor, is to browse reviews of these products on TrustRadius. A robust set of reviews for both IaaS and PaaS products can be crucial in helping to make the right decision.

About the Author

Alan Cooke, Researcher at TrustRadius
Alan Cooke
Alan attended the University College Dublin where he received his BA and MA in English Literature and Philosophy and he received his MBA from HEC Paris. He has held many roles at various companies including Director of Product Management at HP, Dazel, Inquisite, and Convio. His research interests both at work and outside of work include complex, technical topics (ironically).

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