What is the difference between IaaS, PaaS, and SaaS?
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IaaS, PaaS, and SaaS describe how much of the stack the provider operates. With IaaS, the provider supplies virtualized compute, storage, and networking while I manage the guest OS, runtime, application, and data. With PaaS, the provider also operates the application platform, and I deploy code/configuration within its rules. With SaaS, I use a complete provider-operated application and mainly manage users, data, and product configuration.
For example, running a Spring Boot JAR on an EC2 VM is IaaS-like; deploying it to a managed app platform is PaaS-like; using a hosted ticketing product is SaaS. A managed database may be described separately as DBaaS, so PaaS does not automatically include every database.
Moving toward SaaS usually reduces operational control and responsibility, but the exact shared-responsibility boundary varies by product. I read that boundary instead of relying only on the label.
What is the difference between IaaS, PaaS, and SaaS
Direct Answer
IaaS supplies infrastructure primitives while the customer manages more of the OS and application stack. PaaS supplies a managed application platform so the customer mainly deploys code and configuration. SaaS supplies a complete application to its users. Responsibility boundaries vary by product, and managed databases may be classified separately rather than being included in every PaaS.
Code Example
# IaaS: you get a bare VM and install everything yourself
ssh ec2-user@my-ec2-instance
sudo apt-get install -y openjdk-17-jre # you manage the OS + runtime
java -jar order-service.jar
# PaaS: you push code, the platform builds and runs it
git push heroku main # provider handles OS, scaling, TLS
# SaaS: you just consume finished software over the web
# e.g. Gmail, Jira, GitHub — nothing to install or operate
Common Mistakes & Pitfalls
- Choosing IaaS for everything: Freshers often default to EC2 because it feels familiar, then spend weeks configuring load balancers and scaling when configured that PaaS provides out of the box.
- Confusing PaaS with Docker: Thinking Heroku is just Docker hosting—PaaS products may include build systems, routing/TLS, add-on services, and deployment features that raw container hosting doesn't provide.
- Treating internal tools as SaaS: Building a custom admin dashboard and calling it SaaS when it's really just a web application—SaaS means a provider operates the application for its users; tenancy and billing models vary.
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