# On Error Continue versus On Error Propagate

*MuleSoft Developer Study Guide · Handling Errors · Last updated October 28, 2026 · https://www.certifyforce.com/study-guide/mulesoft-developer/handling-errors/on-error-continue-versus-on-error-propagate*

Predict what a caller, an HTTP Listener and a parent flow see when an error is handled by On Error Continue (the owner succeeds with the handler's result) or On Error Propagate (the error is re-thrown), including transactions and default error logging.

- Certification: Salesforce MuleSoft Developer
- Exam section: Handling Errors
- Study guide: https://www.certifyforce.com/study-guide/mulesoft-developer

**Official exam objective:**

> Apply correct processors/syntax to implement on-error continue and on-error propagate handlers, and predict outcomes.

## What the exam expects

- Write an Error Handler with `<on-error-continue>` or `<on-error-propagate>` and predict the status code and body an HTTP Listener returns with its default responses.
- Predict what a parent flow does after a Flow Reference when the referenced flow's error is continued or propagated.
- State what each On-Error component does to a transaction its owner handles.
- Explain why a handled error still appears in the log, and how to switch that off.

Key terms:
- **Owner**: the Flow or Try scope whose Error Handler contains the On-Error component.
- **On Error Continue**: runs its processors and uses their result as the owner's result, as if the owner succeeded.
- **On Error Propagate**: runs its processors, then re-throws the error to the next level up.
- **Default responses**: the HTTP Listener's 200-with-payload success response and 500-with-error-description error response.

## Key facts

| Fact | Detail | Source |
|---|---|---|
| On Error Continue | Owner completes successfully with the handler's result | [On-Error Components](https://docs.mulesoft.com/mule-runtime/latest/on-error-scope-concept) |
| On Error Propagate | Runs, then re-throws; the owner fails | [On-Error Components](https://docs.mulesoft.com/mule-runtime/latest/on-error-scope-concept) |
| HTTP Listener default success response | 200 with the payload as body | [Configure HTTP Listener Source](https://docs.mulesoft.com/http-connector/latest/http-listener-ref) |
| HTTP Listener default error response | 500 with the flow error's description as body | [Configure HTTP Listener Source](https://docs.mulesoft.com/http-connector/latest/http-listener-ref) |
| Default handling | Behaves like On Error Propagate | [Error Handlers](https://docs.mulesoft.com/mule-runtime/latest/error-handling) |
| Error in a referenced flow | Its own handler runs; a propagated error goes to the flow holding the Flow Reference | [Flow Reference Component](https://docs.mulesoft.com/mule-runtime/latest/flowref-about) |
| Flow Reference without `target` | Payload and variable changes in the referenced flow persist | [Flow Reference Component](https://docs.mulesoft.com/mule-runtime/latest/flowref-about) |
| Transactions | Continue commits, Propagate rolls back, only for a transaction the owner handles | [On-Error Components](https://docs.mulesoft.com/mule-runtime/latest/on-error-scope-concept) |
| `logException` | Default `true`: logs the matched error at ERROR before handling | [On-Error Components](https://docs.mulesoft.com/mule-runtime/latest/on-error-scope-concept) |
| `enableNotifications` | Default `true`: fires an `ExceptionNotification` | [On-Error Components](https://docs.mulesoft.com/mule-runtime/latest/on-error-scope-concept) |

## Check yourself

- Why does a Flow Reference with a `target` leave the parent's payload unchanged after the referenced flow runs?
- What are the HTTP Listener's default responses for success and for failure?
- What does `enableNotifications` default to on an On-Error component, and what does it fire?
- Why does a flow with no Error Handler return the same browser result as one with On Error Propagate?

## Sources

- [On-Error Components](https://docs.mulesoft.com/mule-runtime/latest/on-error-scope-concept)
- [Error Handlers](https://docs.mulesoft.com/mule-runtime/latest/error-handling)
- [Configure HTTP Listener Source](https://docs.mulesoft.com/http-connector/latest/http-listener-ref)
- [Flow Reference Component](https://docs.mulesoft.com/mule-runtime/latest/flowref-about)
- [Try Scope](https://docs.mulesoft.com/mule-runtime/latest/try-scope-concept)
- [Raise Error Component](https://docs.mulesoft.com/mule-runtime/latest/raise-error-component-reference)
- [Mule Errors](https://docs.mulesoft.com/mule-runtime/latest/mule-error-concept)

## About the full unit

The "Core concepts", "Exam traps" and "Worked scenario" sections of this unit, its 6 linked practice questions, and unlimited timed mock exams are included with the MuleSoft Developer pack (USD $19): https://www.certifyforce.com/practice-exams