1. IaaS (Infrastructure as a Service):

• Definition: IaaS provides virtualized computing resources over the internet. It offers the fundamental building blocks such as virtual machines, storage, and networking, allowing you to configure your infrastructure as needed.
• Who manages what:
  • Provider manages: Hardware (servers, storage, networking), data centers, virtualization.
  • You manage: Operating systems, applications, middleware, runtime, data, and security.
• Examples: Amazon EC2, Microsoft Azure VMs, Google Compute Engine.
• Use case: IaaS is ideal for businesses that want control over their infrastructure without the burden of maintaining physical hardware. You can configure servers, choose operating systems, and install any software you need.

Analogy: Renting an empty house—you need to bring your own furniture and decorations (OS, applications).

2. PaaS (Platform as a Service):

• Definition: PaaS provides a platform that allows developers to build, test, and deploy applications without worrying about the underlying infrastructure. It includes everything from servers and storage to middleware and databases.
• Who manages what:
  • Provider manages: Hardware, networking, storage, virtualization, operating system, middleware, and runtime.
  • You manage: Applications and data.
• Examples: Heroku, Google App Engine, AWS Elastic Beanstalk, Microsoft Azure App Services.
• Use case: PaaS is ideal for developers who want to focus solely on writing code and deploying applications without managing infrastructure or runtime environments. It's a great option for building web apps or microservices quickly.

Analogy: Renting a fully-furnished apartment—you just bring your personal items (apps, data) and start using it.

3. SaaS (Software as a Service):

• Definition: SaaS delivers fully functional software applications over the internet. Users access the software via a web browser or API, without worrying about infrastructure or platform management.
• Who manages what:
  • Provider manages: Everything, including the hardware, infrastructure, application, data, security, updates, and maintenance.
  • You manage: Just the use of the software (e.g., configuring settings or entering data).
• Examples: Gmail, Google Workspace, Microsoft 365, Salesforce, Dropbox.
• Use case: SaaS is perfect for end-users or businesses that want to use fully functional software without handling the complexities of installation, infrastructure, or maintenance.

Analogy: Using a hotel—you just check in and use the amenities without worrying about maintenance or management.

Comparison Table: