# Client caching and response reuse

*MuleSoft Developer II Study Guide · Implement performant and reliable Mule applications · Last updated November 7, 2026 · https://www.certifyforce.com/study-guide/mulesoft-developer-ii/implement-performant-and-reliable-mule-applications/client-caching-and-response-reuse*

Choose suitable API results for client caching, configure keys, copying, expiry and synchronization separately, and reuse the complete intended computation.

- Certification: Salesforce MuleSoft Developer II
- Exam section: Implement performant and reliable Mule applications
- Study guide: https://www.certifyforce.com/study-guide/mulesoft-developer-ii

**Official exam objective:**

> Implement client-side caching of API invocations for performance.

## What the exam expects

- Select API interactions whose results can safely be reused.
- Define the complete cached computation and its request identity.
- Distinguish eligibility, copying, response generation and expiration.
- Manage concurrent initial fills and the storage configuration deliberately.

A **cache key** identifies equivalent requests; a **hit** reuses stored output; a **miss** executes the computation; a **strategy** defines caching behavior; **expiry** limits reuse over time; **synchronization** coordinates competing access. This lesson describes the Mule4.6 client Cache scope, rather than gateway server-policy caching.

## Key facts

| Fact | Detail | Source |
|---|---|---|
| Suitable data | Frequent repeated results must tolerate temporary staleness. | [Caching guidance](https://docs.mulesoft.com/mule-runtime/4.6/tuning-caching) |
| Multiple processors | One scope can cache their combined generated response. | [Cache scope](https://docs.mulesoft.com/mule-runtime/4.6/cache-scope) |
| False filter | Executes enclosed work without reading or saving cached responses. | [Configure Cache](https://docs.mulesoft.com/mule-runtime/4.6/cache-scope-to-configure) |
| Response eligibility | A nonrepeatable generated stream is not cached. | [Cache scope](https://docs.mulesoft.com/mule-runtime/4.6/cache-scope) |
| Custom key | Use the Key Expression or documented key-generator interface. | [Caching strategy](https://docs.mulesoft.com/mule-runtime/4.6/cache-scope-strategy) |
| Mutable event data | Uses the Serializable event copy setting. | [Caching strategy](https://docs.mulesoft.com/mule-runtime/4.6/cache-scope-strategy) |
| Custom returned response | Uses the Advanced Response Generator extension point. | [Caching strategy](https://docs.mulesoft.com/mule-runtime/4.6/cache-scope-strategy) |
| Lifetime | Configure expiration in the strategy's Object Store. | [Cache scope](https://docs.mulesoft.com/mule-runtime/4.6/cache-scope) |
| Competing fills | Synchronization coordinates calculation and retrieval with a cost. | [Caching strategy](https://docs.mulesoft.com/mule-runtime/4.6/cache-scope-strategy) |

## Check yourself

- Why can a team create a caching strategy before opening a particular Cache scope panel?
- When should a strategy select Global Reference for its Object Store configuration?
- What configuration ownership does Edit Inline create?

## Sources

- [Cache scope, Mule4.6](https://docs.mulesoft.com/mule-runtime/4.6/cache-scope)
- [Caching strategy, Mule4.6](https://docs.mulesoft.com/mule-runtime/4.6/cache-scope-strategy)
- [Configure Cache scope, Mule4.6](https://docs.mulesoft.com/mule-runtime/4.6/cache-scope-to-configure)
- [Caching performance, Mule4.6](https://docs.mulesoft.com/mule-runtime/4.6/tuning-caching)

## About the full unit

The "Core concepts", "Exam traps" and "Worked scenario" sections of this unit, its 10 linked practice questions, and unlimited timed mock exams are included with the MuleSoft Developer II pack (USD $19): https://www.certifyforce.com/practice-exams