IaaS, PaaS and SaaS Explained with Real Examples
Basics4 minInnovialabs editorial team
In short
IaaS gives you virtual hardware that you configure yourself, PaaS gives you a ready platform where you just deploy code, and SaaS gives you finished software you use in a browser.
The short answer
The three models differ in how much of the work the provider takes on and how much stays with you. A handy analogy is food:
- IaaS: you rent a kitchen with a stove and cookware, but you do the cooking.
- PaaS: you get a ready kitchen with a sous-chef; you bring the recipe, the rest is handled.
- SaaS: you go to a restaurant and simply order.
Who manages what
| Layer | Own server | IaaS | PaaS | SaaS |
|---|---|---|---|---|
| Data and access | You | You | You | You |
| Application (code) | You | You | You | Provider |
| Runtime, libraries | You | You | Provider | Provider |
| Operating system | You | You | Provider | Provider |
| Virtualization, network, storage | You | Provider | Provider | Provider |
| Physical servers, data center | You | Provider | Provider | Provider |
Note the first row: you are always responsible for your data and access rights, in every model. This is known as the shared responsibility model.
IaaS: infrastructure as a service
You get virtual machines, disks, networks and load balancers. You install the OS, configure the environment, deploy the application and maintain everything.
Examples: Amazon EC2, Google Compute Engine, Azure Virtual Machines, and VPS plans from hosting providers.
Choose it when:
- you need full control over the environment and network;
- your stack is unusual or you have special security requirements;
- you have a DevOps engineer or system administrator.
Impact on team and budget: the most flexible model, but also the most manual work: updates, monitoring, backups, scaling. Your costs include not only the resource bill but also specialists' time.
PaaS: platform as a service
You push code, and the platform builds, runs, scales and patches the environment. PaaS often includes managed databases, queues and logging.
Examples: Heroku, Google App Engine, Azure App Service, AWS Elastic Beanstalk, Vercel, Render.
Choose it when:
- you are a small team that wants to work on the product, not on servers;
- your stack is standard: Node.js, Python, PHP, Go, Java;
- shipping updates quickly matters.
Impact on team and budget: less administration and a faster launch. In exchange you get less control, platform limits and a risk of vendor lock-in. As load grows, PaaS can cost more than equivalent infrastructure on IaaS, so review the bill periodically.
SaaS: software as a service
A finished product you use in a browser or app on a subscription. Nothing to install or maintain.
Examples: Google Workspace, Microsoft 365, Slack, Notion, Salesforce, amoCRM, cloud Bitrix24.
Choose it when:
- the task is standard: email, documents, CRM, accounting, task tracking;
- building your own makes no sense because an existing product covers your needs.
Impact on team and budget: minimal technical work and a predictable subscription. The limits: customization only within what the product allows, and your data lives with the provider. Always check whether you can export your data if you decide to leave.
How to choose
- Is it a standard business task? Look for SaaS first.
- Building your own product or service? Start with PaaS if the stack is standard and the team is small.
- Need special configuration, network control or cost optimization at high load? Move to IaaS.
In practice companies mix models: CRM on SaaS, the website on PaaS, heavy data processing on IaaS.
Common mistakes
- Assuming security in the cloud is the provider's job. Misconfigured access rights are your responsibility.
- Choosing IaaS with nobody to run it.
- Building from scratch what SaaS already offers, spending budget on features that are not unique.
- Not planning an exit from PaaS or SaaS: data export and code portability.