Instead of buying servers, a startup rents computing power by the hour. That is cloud computing — using remote servers for storage and processing over the internet. The cloud is not a place. It is a business model and a technical architecture. Someone else owns the hardware. You pay for what you use.

Amazon launched AWS in 2006. Microsoft, Google, and others followed. Today, most websites, apps, and enterprise systems run on cloud infrastructure. The cloud offers elasticity: scale up during a traffic spike, scale down when it passes.

Service models

• IaaS: rent virtual machines and storage
• PaaS: rent a platform for deploying apps
• SaaS: use software over the internet
• Serverless: run code without managing servers

The cloud has risks. Outages can take down thousands of services at once. Data sovereignty laws may require keeping data in specific countries. Vendor lock-in makes it hard to switch providers. Convenience comes with dependency.