Infrastructure as a Service (IaaS) is a cloud model where a provider rents you the raw building blocks of computing: virtual servers, storage and networking. You pay for what you use, usually by the hour or second, and you manage the operating system and everything above it. The provider keeps the physical machines, power and cooling running in their data centre.
Think of it like leasing an empty warehouse instead of buying one. The landlord handles the building, the roof and the electricity, but the shelving, the layout and the stock are all yours to decide. IaaS works the same way: you get bare servers and full control, but you are responsible for installing and securing your own software. If you want less to manage, platform services take more of that work off your hands. Most IaaS platforms can also grow capacity on demand when traffic spikes.
The big names are AWS EC2, Google Compute Engine and Microsoft Azure. They turned servers into something you can switch on in minutes and switch off when you are done, rather than ordering hardware that takes weeks to arrive.
The catch is that control cuts both ways. Patching the OS, configuring the firewall and keeping the machine secure all land on your team, not the provider. And because every provider has its own consoles and APIs, moving a setup elsewhere later can be a real chore, a flavour of vendor lock-in worth weighing before you commit.
At TopDevs we use IaaS when a client needs full control over their environment, and we set it up so the bill tracks real usage instead of paying for idle machines.
