Overview
IaaS and PaaS are cloud service models that differ in how much of the technology stack the provider abstracts away from you. IaaS hands you raw virtualized infrastructure and leaves the OS, runtime, and app management to you, while PaaS also manages the OS and runtime so you only push application code. The distinction matters because it determines your team’s operational burden, control, and how fast you can ship.
Comparison Diagram
Comparison Table
| Aspect | IaaS | PaaS |
|---|---|---|
| Provisioning unit | Virtual machines, block storage, virtual networks | Application slots or containers bound to a managed runtime |
| OS and runtime management | Customer installs, configures, and patches OS and runtime | Provider installs and patches OS and runtime automatically |
| Deployment workflow | Customer scripts server setup, then deploys app via SSH/config management | Customer pushes code (git push, CI artifact); platform builds and deploys |
| Scaling | Customer configures auto-scaling groups and load balancers manually | Platform scales instances automatically based on traffic or rules |
| Customization and control | Full root access, any OS, any custom software stack | Constrained to platform-supported languages, frameworks, and versions |
| Failure recovery | Customer builds and monitors health checks, failover, and backups | Platform handles instance replacement and basic health monitoring |
| Vendor lock-in | Low — standard VM images port across most cloud providers | Higher — apps depend on platform-specific APIs and build conventions |
| Typical adopter | Infrastructure/ops teams migrating or replicating existing systems | Application developers who want to ship features without managing servers |
Key Differences
- IaaS gives you a virtual machine; PaaS gives you a managed runtime for your code
- PaaS abstracts away OS patching, which IaaS leaves entirely to the customer
- IaaS deployment means configuring servers yourself; PaaS deployment is typically a git push
- PaaS trades flexibility for speed, increasing vendor lock-in compared to IaaS
- Auto-scaling is built into PaaS, whereas IaaS requires customer-configured scaling groups
When to Use Each
IaaS
- Lift-and-shift migration: IaaS lets you replicate an existing on-prem server setup with minimal changes to the OS or software stack.
- Custom or legacy software stacks: Full root access lets you run non-standard runtimes, kernel modules, or licensed software PaaS platforms don’t support.
- Fine-grained cost and performance tuning: Direct control over VM sizing, storage type, and networking lets ops teams optimize for specific workloads.
PaaS
- Rapid application deployment: Developers push code and let the platform handle builds, patching, and scaling without provisioning servers.
- Small teams without dedicated ops: PaaS removes the need for in-house expertise in OS hardening, patch cycles, and infrastructure monitoring.
- Standard web and API workloads: Common frameworks and languages are natively supported, so there’s little benefit to managing the OS layer yourself.