Cloud computing has transformed from a specialized enterprise technical choice into the fundamental utility powering virtually all digital experiences.
The Shared Responsibility Model
At its core, cloud computing is about renting computing resources—processing power, storage, and networking—from third-party data centers. The industry is divided into three primary service tiers:
1. Infrastructure as a Service (IaaS)
IaaS provides virtualized raw computing resources. The cloud provider manages the physical data centers, servers, power supplies, and network virtualization. You rent virtual machines and raw storage volumes, and you are entirely responsible for installing the operating system, managing security patches, and configuring application software.
2. Platform as a Service (PaaS)
PaaS abstracts away server operating systems and hardware maintenance. Developers simply deploy application code, while the cloud provider automatically manages server provisioning, operating system updates, network routing, and auto-scaling.
3. Software as a Service (SaaS)
SaaS delivers fully functional end-user applications accessible directly through a web browser or mobile app. The vendor manages the entire stack from hardware to user interface (e.g., email platforms, project management tools, and online document editors).
Summary Table
| Tier | Provider Manages | You Manage |
|---|---|---|
| IaaS | Physical hardware, virtualization | OS, runtime, middleware, data, code |
| PaaS | Hardware, OS, runtime, scaling | Application code, customer data |
| SaaS | Entire stack and infrastructure | User configuration, access rights |