IaaS (Infrastructure as a Service), PaaS (Platform as a Service) and SaaS (Software as a Service) are cloud computing service models for business.
IaaS (Infrastructure as a Service)
IaaS (Infrastructure as a Service) is a cloud computing service that provides the computing infrastructure, physical or virtual machines and other resources like virtual-machine disk image library, block and file-based storage, firewalls, load balancers, IP addresses, virtual local area networks etc.
Examples of IaaS:
Think about Amazon EC2 where we have full control over the infrastructure and we can easily get the above mentioned servies. So we can say when we have the software and the platform ready but we need the hardware to run our software then we should plan to use IaaS.
Amazon EC2, Google Compute Engine, Windows Azure, Rackspace.
PaaS (Platform as a Service)
PaaS (Platform as a Service) is a cloud computing service that provides computing platforms which typically includes operating system, programming language execution environment, database, web server etc.
Examples of PaaS
Think about Heroku where we don’t have full control but we can use it as a platform and we can easily run our app in that platform. When we have a software ready and we want to deploy and run on a publicly available platform then we should plan to use PaaS.
AWS Elastic Beanstalk, Heroku, Windows Azure (mostly used as PaaS), Force.com, OpenShift, Apache Stratos, Magento Commerce Cloud.
While in SaaS (Software as a Service)
SaaS (Software as a Service) is a cloud computing service that provides the access to application software where we don’t have to worry about the installation, setup and running of the application. Service provider will do that for us. we just have to pay and use it.
Examples of SaaS
Think about Gmail where we are not worried about the setup and installation. We just use it according to our needs. The Gmail service provider Google is doing everything for us. So we can say that when we simply want to make use of a software and don’t want to worry about the setup, installation and maintenance then we should plan to use SaaS.
BigCommerce, Google Apps, Salesforce, Dropbox, MailChimp, ZenDesk, DocuSign, Slack, Hubspot.