What are IaaS and PaaS?

IaaS and PaaS: definition and context

Both terms describe how much responsibility a cloud provider takes on. With Infrastructure as a Service, you receive the technical foundation as a rental service: virtual machines, storage and networks. Platform as a Service goes one step further and also supplies the operating system, runtime environment and often databases, so developers only manage their code and data.

Together with Software as a Service, they form the classic cloud service models. The higher up you start, the less you have to operate yourself—but the less room you have for customization. This is known as the shared responsibility model: the provider secures the platform, and you secure what you run on it.

How responsi­bili­ties are divided

With IaaS, the provider operates the data center, hardware and virtualization. You install the operating system, apply updates, set firewall rules and look after the application. That offers maximum freedom but requires administration know-how. Typical providers are the large hyperscalers such as AWS, Microsoft Azure and Google Cloud, as well as European hosting companies.

With PaaS, you upload your application to a prepared environment. The provider handles operating system updates, scaling and often backups. In return, its rules apply: supported programming languages, versions and configuration options. If you have special requirements beyond that, you reach the limits sooner than with IaaS.

Real-world example: a supplier with legacy software and a customer portal

A mid-sized supplier runs older industry software that must run on a specific Windows server. IaaS suits this case: the virtual machine moves to the cloud almost unchanged, and the team keeps full control over the operating system and installation.

The new customer portal, which shows order status and delivery notes, is instead built as a modern web application and run on a PaaS platform. The provider handles runtime updates and adjusts to load peaks—so the small IT team can focus on the portal’s features rather than server maintenance.

Benefits, limits and decision guide

Both models replace investment in your own hardware with monthly usage costs and can be expanded quickly. The limits lie in dependence on the provider and in ongoing costs, which can exceed the purchase of your own servers under constant high load. A typical mistake: choosing IaaS without anyone being responsible for maintaining and securing the servers.

Nano Concepts helps you make this decision: we assess your existing applications, plan the right target architecture and, if you wish, take over migration, security and ongoing operation—from a single virtual machine to a full platform solution, each including monitoring, backups and clear documentation.

• IaaS if you need full control over the operating system and software
• PaaS if you want to run your own applications without server administration
• Put responsibilities for updates, backups and security in writing
• Check provider dependence and exit options in advance
• Compare costs under constant load against fixed-price offers