# IaaS, PaaS and SaaS service models

*MuleSoft Integration Foundations Study Guide · Recognize and interpret essential integration concepts and terminology · Last updated November 2, 2026 · https://www.certifyforce.com/study-guide/mulesoft-integration-foundations/essential-integration-concepts-and-terminology/iaas-paas-and-saas-service-models*

How MuleSoft stacks the three cloud service models, with SaaS on top, PaaS in the middle and IaaS at the bottom, what each one delivers and leaves to the customer, and why CloudHub is classed as an iPaaS, a PaaS subcategory for integration.

- Certification: Salesforce MuleSoft Integration Foundations
- Exam section: Recognize and interpret essential integration concepts and terminology
- Study guide: https://www.certifyforce.com/study-guide/mulesoft-integration-foundations

**Official exam objective:**

> Distinguish between Infrastructure as a Service (IaaS), Platform as a Service (PaaS), and Software as a Service (SaaS).

## What the exam expects

- Classify a cloud offering as IaaS, PaaS or SaaS from what the provider supplies and what the customer still builds or installs.
- Place the three models in MuleSoft's cloud stack and say which layer is the foundation for the others.
- Distinguish the two PaaS subcategories, aPaaS and iPaaS, and classify CloudHub as an iPaaS.
- Explain the IaaS benefits MuleSoft names: on-demand scaling, pay-as-you-go pricing and lower capital spending.

Key terms:
- **Cloud service**: computing resources provided over the internet on demand.
- **IaaS**: basic computing resources (storage, hardware, servers, networking) provided as a virtualized environment over the internet.
- **PaaS**: a development platform for building and running applications in the cloud.
- **SaaS**: business applications offered by vendors that enterprises use to run day-to-day operations.
- **iPaaS**: a PaaS whose services are geared towards integration.

## Key facts

| Fact | Detail | Source |
|---|---|---|
| Stack order | SaaS at the top, PaaS in the middle, IaaS at the bottom | [IaaS overview](https://www.mulesoft.com/resources/cloudhub/iaas-infrastructure-as-a-service) |
| IaaS role | Virtualized hardware that is the foundation for SaaS and PaaS | [IaaS overview](https://www.mulesoft.com/resources/cloudhub/iaas-infrastructure-as-a-service) |
| IaaS pricing | Pay-as-you-go: pay only for resources used in a period | [IaaS overview](https://www.mulesoft.com/resources/cloudhub/iaas-infrastructure-as-a-service) |
| Who maintains IaaS infrastructure | The IaaS vendor configures and maintains it | [IaaS overview](https://www.mulesoft.com/resources/cloudhub/iaas-infrastructure-as-a-service) |
| PaaS subcategories | aPaaS and iPaaS | [IaaS overview](https://www.mulesoft.com/resources/cloudhub/iaas-infrastructure-as-a-service) |
| iPaaS extras beyond PaaS | Intermediation of data and events, orchestration, REST/SOAP service container, security, monitoring, tooling | [CloudHub FAQ](https://docs.mulesoft.com/cloudhub/cloudhub-faq) |
| CloudHub classification | iPaaS; CloudHub 2.0 is a fully managed, containerized iPaaS | [CloudHub FAQ](https://docs.mulesoft.com/cloudhub/cloudhub-faq), [CloudHub 2.0 Overview](https://docs.mulesoft.com/cloudhub-2/) |

## Check yourself

- Which tier of the traditional application-middleware-hardware architecture does PaaS correspond to?
- Why does MuleSoft call a seasonal marketing campaign a good short-term IaaS use case?
- When does an aPaaS product fit better than an iPaaS product?
- Which capabilities does an iPaaS add on top of the base PaaS expectations of multi-tenancy, elasticity and reliability?

## Sources

- [IaaS: Infrastructure as a Service](https://www.mulesoft.com/resources/cloudhub/iaas-infrastructure-as-a-service)
- [Cloud service and application integration](https://www.mulesoft.com/resources/cloudhub/what-is-cloud-service)
- [CloudHub Overview](https://docs.mulesoft.com/cloudhub/)
- [CloudHub FAQ](https://docs.mulesoft.com/cloudhub/cloudhub-faq)
- [CloudHub 2.0 Overview](https://docs.mulesoft.com/cloudhub-2/)
- [Deployment Options](https://docs.mulesoft.com/runtime-manager/deployment-strategies)
- [Anypoint Platform Glossary](https://docs.mulesoft.com/general/glossary)

## About the full unit

The "Core concepts", "Exam traps" and "Worked scenario" sections of this unit, its 3 linked practice questions, and unlimited timed mock exams are included with the MuleSoft Integration Foundations pack (USD $19): https://www.certifyforce.com/practice-exams