# Request-reply, one-way, multicast, batch and stream patterns

*MuleSoft Integration Foundations Study Guide · Explain the common technical complexities and patterns in integration development · Last updated November 2, 2026 · https://www.certifyforce.com/study-guide/mulesoft-integration-foundations/technical-complexities-and-patterns-in-integration-development/request-reply-one-way-multicast-batch-and-stream-patterns*

How the five interaction patterns differ: blocking request-reply, one-way messaging through a queue, multicast through an Anypoint MQ message exchange, Mule batch jobs for larger-than-memory record sets, and Mule 4 repeatable streams for large payloads.

- Certification: Salesforce MuleSoft Integration Foundations
- Exam section: Explain the common technical complexities and patterns in integration development
- Study guide: https://www.certifyforce.com/study-guide/mulesoft-integration-foundations

**Official exam objective:**

> Describe the differences between the request-reply, one-way, multicast, batch, and stream interaction patterns.

## What the exam expects

- Recognize request-reply as the blocking pattern where the caller waits for the answer before it continues.
- Recognize one-way (fire-and-forget) messaging through a queue, where sender and receiver never need to be present at the same time.
- Distinguish multicast (one message to several receivers at once) from a single queue that delivers each message to one consumer.
- Describe what a Mule Batch Job adds: record splitting, persistent queues, resumable processing and a results report.
- Explain how Mule 4 streams large payloads with repeatable streams by default.

Key terms:
- **Request-reply**: a synchronous, blocking call; the client waits for the server's response.
- **One-way**: an asynchronous send; the sender continues without waiting for a reply.
- **Multicast**: one published message delivered simultaneously to several receivers.
- **Batch**: reliable, asynchronous processing of a large record set in phases.
- **Stream**: content consumed incrementally instead of loaded whole, buffered so it can be reread.

## Key facts

| Fact | Detail | Source |
|---|---|---|
| Synchronous model | Blocking; the client waits for the response | [Asynchronous APIs](https://www.mulesoft.com/api/what-is-asynchronous-api) |
| Queue consumption | Retrieved messages are locked and invisible to other consumers | [Anypoint MQ Overview](https://docs.mulesoft.com/mq/) |
| Exchange limits | 10 MB message; 450 bound queues; 25 with routing rules | [Message exchanges](https://docs.mulesoft.com/mq/mq-exchanges) |
| Batch reliability | Persistent queues; resumes after a crash or redeployment | [Batch Processing](https://docs.mulesoft.com/mule-runtime/latest/batch-processing-concept) |
| Batch edition | Enterprise Edition only, not the Mule kernel | [Batch Processing](https://docs.mulesoft.com/mule-runtime/latest/batch-processing-concept) |
| Default stream strategy | File-stored repeatable (EE), 512 KB in memory first | [Streaming in Mule Apps](https://docs.mulesoft.com/mule-runtime/latest/streaming-about) |

## Check yourself

- Why can an app never consume directly from an Anypoint MQ message exchange?
- When does an in-memory repeatable stream make the app fail?
- What happens to a locked Anypoint MQ message whose consumer crashes?

## Sources

- [What are asynchronous APIs?](https://www.mulesoft.com/api/what-is-asynchronous-api)
- [What is a messaging queuing service?](https://www.mulesoft.com/integration/what-is-a-message-queuing-service)
- [Anypoint MQ Overview](https://docs.mulesoft.com/mq/)
- [Sending Messages to Multiple Queues Using Message Exchanges](https://docs.mulesoft.com/mq/mq-exchanges)
- [Batch Processing](https://docs.mulesoft.com/mule-runtime/latest/batch-processing-concept)
- [Streaming in Mule Apps](https://docs.mulesoft.com/mule-runtime/latest/streaming-about)

## About the full unit

The "Core concepts", "Exam traps" and "Worked scenario" sections of this unit, its 5 linked practice questions, and unlimited timed mock exams are included with the MuleSoft Integration Foundations pack (USD $19): https://www.certifyforce.com/practice-exams