Software as a Service (SaaS), Platform as a Service (PaaS), and Infrastructure as a Service (IaaS)

In cloud computing, you might hear the terms SaaS, PaaS and IaaS.  These are simply different logical layers in the stack.  You can visualize it like this:

SaaS PaaS and IaaS

As you move up the stack, you increase abstraction.  As you move down the stack, you increase control.  Here is a brief summary of each term:

  • Infrastructure as a Service (IaaS) – In this case, computing resources (compute, storage, and network) are exposed as a capability.  Instead of owning, managing or controlling the underlying infrastructure, you rent the infrastructure, as a service.  An example is  Amazon Elastic Cloud Compute (EC2).
  • Platform as a Service (Paas) – In this case, programming platforms and tools (such as java, python, or .NET) and/or building blocks and APIs for building cloud-based applications and services are made exposed as a capability.  Examples include Amazon Simple Storage Service (S3), Azure Storage, and
  • Software as a Service (SaaS) – In this case, applications are exposed as a service running on a cloud infrastructure.  Examples include and Microsoft Office Online.

For my related posts on cloud, see:

Comments (1)

  1. This nicely explains all the different acronyms used for the many facets of cloud computing. Many people are still new to the idea that these services can be bought from another company saving a great deal of time and money.