SaaS, PaaS and IaaS explained

SaaS (Software-as-a-Service)

You can sign up and use the software directly: e.g. Zendesk, Paypal, even more customer-oriented ones like Twitter, Facebook, Instagram

PaaS (Platform-as-a-Service)

You can build your software on top of the platform: e.g. Heroku, SalesForce, Google App Engine Besides building everything from the platform level, you can also leverage the benefits from some Backend-as-a-Service in the market. E.g. Skygear, Firebase, Kii, Kinvey

IaaS (Infrastructure-as-a-Service)

Provides you some place (virtual machines) to deploy your app. e.g. Amazon Web Service EC2, Digital Ocean, RackSpace Cloud On-Premises Deployment So you have your own datacenter and servers — it’s completely customized

Examples of IaaS, Paas, and SaaS