Cloud Infrastructure 101: IaaS, PaaS, and SaaS in Action

Cloud services come in three common models. IaaS, PaaS, and SaaS help teams control, deploy, and use software in different ways. Understanding who handles what makes it easier to design solutions that fit goals and budgets.

IaaS: Infrastructure as a Service

IaaS offers raw computing resources—virtual machines, storage, and networks. You install and manage the operating system, middleware, and applications. The provider takes care of the physical servers, power, and cooling. This model gives you the most control, but also the most responsibility.

  • You control the guest OS and software stack
  • You scale by adding VMs or storage
  • Costs reflect usage and resources

PaaS: Platform as a Service

PaaS provides a ready-made platform for developing and running apps. You focus on code and features while the provider handles the runtime, middleware, and OS updates. It speeds up delivery and reduces ops work.

  • Faster deployment and iteration
  • Built-in scaling and updates
  • Less control over the underlying stack

SaaS: Software as a Service

SaaS delivers software over the web. You use an app without installing it locally. The provider handles maintenance, security, and backups. This is the lowest burden model for end users.

  • No installation or maintenance
  • Always up to date
  • Subscription pricing

Choosing the right model for your project

Think about control, speed, and cost. If you need full control of the environment, IaaS fits. If you want faster development with less ops, PaaS works well. If the goal is ready-made software for users, SaaS is best.

  • Balance between control and simplicity
  • Deployment speed and team skills
  • Long-term costs and vendor lock-in

A practical example

Imagine you build a new web app for customers. Start with a PaaS to ship quickly. If traffic grows or you need more database tuning, add IaaS resources for the data layer. For non-core tools like email or file sharing, consider SaaS options to reduce management tasks.

Key Takeaways

  • IaaS, PaaS, and SaaS describe who manages the infrastructure and software.
  • Use the model that fits your control needs, speed goals, and cost constraints.
  • Real-world flows often mix models to balance agility and responsibility.