The three major Cloud Computing Offerings are:

  1. Software as a Service (SaaS)
  2. Platform as a Service (PaaS)
  3. Infrastructure as a Service (IaaS)

1. SaaS (Software as a Service)

SaaS or software as a service is a software distribution model in which applications are hosted by a vendor or service provider and made available to customers over a network (internet).

2. PaaS (Platform as a Service)

Platform as a service, is referred as PaaS, it provides a platform and environment to allow developers to build applications and services. This service is hosted in the cloud and accessed by the users via internet.

3. IaaS (Infrastructure as a Service)

IaaS (Infrastructure As A Service) is one of the fundamental service model of cloud computing alongside PaaS( Platform as a Service). It provides access to computing resources in a virtualized environment “the cloud” on internet. It provides computing infrastructure like virtual server space, network connections, bandwidth, load balancers and IP addresses. The pool of hardware resource is extracted from multiple servers and networks usually distributed across numerous data centers.

This provides redundancy and reliability to IaaS. (PaaS) that are available for the users to build and host an application are: Amazon Web Services: AWS offers virtual compute, storage, networking & complete computing stacks. It is known for its on-demand services namely Elastic Compute Cloud (EC2) and Simple Storage Service (S3). 

Google AppEngine: Launched in 2008, it provides applications (SaaS) and raw hardware (IaaS). App Engine managed infrastructure, provides a development platform to create apps, leveraging Google's infrastructure as a hosting platform.

Microsoft Azure: It is also a scalable runtime environment for web & distributed applications. It provides additional services such as support for storage( relational data & blobs), networking, caching, content, content delivery & others.