IaaS versus PaaS versus SaaS

Another important distinction is to be made with respect to the amount of work done by the user or by the cloud platform provider. Let us take a look at this distinction with the help of the following service levels:

• Infrastructure as a Service (IaaS): At the minimum level, IaaS, the cloud provider, handles the machines, their virtualization and the required networking. The user is responsible for everything else—OS, middleware, data, and application software. The provider is the host of the resources on which the user builds the infrastructure. Google compute Engine, SQL, DNS, or load balancing are examples of IaaS services within the GCP.
• Platform as a service (PaaS): In a PaaS offering, the user is only responsible for the software and the data. Everything else is handled by the cloud provider. The provider builds the infrastructure while the user deploys the software. The main advantage of PaaS over IaaS, besides the reduced workload and need for sysadmin resources, is the automatic scaling for web applications. The appropriate number of resources are automatically allocated as demand fluctuates. Examples of PaaS services include Heroku or the Google App Engine.
• Software as a service (SaaS): In SaaS, the provider is a software company offering services online while the user consumes the service that are provided. Think Uber, Facebook, or Gmail.

While being mostly an IaaS provider, the GCP also has some PaaS offerings such as the Google App Engine. And its ML APIs (text, speech, video, and image) can be considered as SaaS.