Cloud computing is the provision of IT resources (servers, storage, databases, software) on demand over the Internet, billed by usage rather than bought and installed on site.
Instead of buying and hosting machines, a company rents capacity from a provider and adjusts it to its needs. There are three main levels: IaaS (raw infrastructure), PaaS (a platform to deploy your code) and SaaS (ready-to-use software). The cloud can be public, private or hybrid.
The cloud made it possible to build digital products quickly without upfront hardware investment. In return, it raises questions about long-term cost, dependence on a provider and data location, hence the rise of FinOps and sovereign cloud offerings.
Why it matters when hiring
"Cloud experience" on a resume covers almost anything. Ask which provider, at what level (deploying an app or designing the network and security architecture), and with which automation tools (Terraform, Kubernetes). A cloud architect, a DevOps engineer and a developer deploying on a managed platform do not do the same job. Certifications help, but a real project in production counts for more.