# Caching and Object Store Design

*MuleSoft Platform Architect Study Guide · Meeting API quality goals · Last updated November 13, 2026 · https://www.certifyforce.com/study-guide/mulesoft-platform-architect/meeting-api-quality-goals/caching-and-object-store-design*

Choose temporary state and caching boundaries, configure coherent Mule cache access and sharing, and apply HTTP freshness, validation, invalidation and explicitly permitted stale reuse.

- Certification: Salesforce MuleSoft Platform Architect
- Exam section: Meeting API quality goals
- Study guide: https://www.certifyforce.com/study-guide/mulesoft-platform-architect

**Official exam objective:**

> Design, describe, and differentiate between scenarios that use an OS or caching.

## What the exam expects

- Choose a temporary object store, replaceable cache or long-term system of record.
- Configure meaningful keys, synchronized cache access and deliberate sharing boundaries.
- Calculate HTTP age and remaining freshness across intermediaries.
- Distinguish validation, invalidation and explicitly allowed stale reuse.
- Interpret request directives and response metadata within their documented scope.

An **object store** keeps keyed application values; a **cache** keeps reusable results; **freshness** permits HTTP reuse without validation; a **validator** checks a stored representation; **invalidation** removes or makes that representation unusable until validation ([Custom-policy caching](https://docs.mulesoft.com/mule-gateway/policies-custom-mule-4-caching), [HTTP caching](https://www.rfc-editor.org/rfc/rfc9111.html)). The HTTP rules below concern implementations of the cited RFCs; a Mule object store or Cache scope is not itself a promise to implement every HTTP cache directive.

## Key facts

| Fact | Detail | Source |
| --- | --- | --- |
| Temporary storage | Object Store is suitable for temporary values; long-term history needs lifecycle and audit design. | [Storage considerations](https://blogs.mulesoft.com/api-integration/storage-for-mule-applications/) |
| Cache keys | Equivalent requests need the same generated key. | [Caching strategy](https://docs.mulesoft.com/mule-runtime/4.6/cache-scope-strategy) |
| Locking hazard | Same-strategy invalidation inside a synchronized Cache execution can block progress. | [Invalidation](https://docs.mulesoft.com/mule-runtime/4.6/cache-scope-invalidate) |
| Custom-policy sharing | Common store name and global-sharing property require broader isolation review. | [Custom-policy caching](https://docs.mulesoft.com/mule-gateway/policies-custom-mule-4-caching) |
| Age propagation | Current age includes corrected initial age and local residence. | [HTTP caching](https://www.rfc-editor.org/rfc/rfc9111.html) |
| Remaining freshness | min-fresh concerns future freshness; max-age concerns current age. | [HTTP caching](https://www.rfc-editor.org/rfc/rfc9111.html) |
| Disconnected revalidation | must-revalidate requires an error if stale content cannot be successfully validated. | [HTTP caching](https://www.rfc-editor.org/rfc/rfc9111.html) |
| HEAD mismatch | Changed validators or length make the old GET response stale. | [HTTP caching](https://www.rfc-editor.org/rfc/rfc9111.html) |
| Stale allowances | Error recovery and nonblocking revalidation have distinct conditions and bounded windows. | [Stale extensions](https://www.rfc-editor.org/rfc/rfc5861.html) |

## Check yourself

- Why does an unknown Cache-Control extension not invalidate the entire field?
- When a request contains a cache directive, what does that establish about the same directive appearing in the response?
- When an HTTP response lacks Age, can that absence alone establish origin contact?

## Sources

- [HTTP Caching (RFC 9111)](https://www.rfc-editor.org/rfc/rfc9111.html)
- [HTTP Cache-Control Extensions for Stale Content (RFC 5861)](https://www.rfc-editor.org/rfc/rfc5861.html)
- [Invalidate Cache Entries — Mule Runtime 4.6](https://docs.mulesoft.com/mule-runtime/4.6/cache-scope-invalidate)
- [Set Up a Caching Strategy — Mule Runtime 4.6](https://docs.mulesoft.com/mule-runtime/4.6/cache-scope-strategy)
- [Data storage considerations for Mule applications](https://blogs.mulesoft.com/api-integration/storage-for-mule-applications/)
- [Caching in a Custom Policy for Mule 4](https://docs.mulesoft.com/mule-gateway/policies-custom-mule-4-caching)

## About the full unit

The "Core concepts", "Exam traps" and "Worked scenario" sections of this unit, its 11 linked practice questions, and unlimited timed mock exams are included with the MuleSoft Platform Architect pack (USD $19): https://www.certifyforce.com/practice-exams