# REST routes for journeys, sends and content

*Marketing Cloud Engagement Developer Study Guide · API · Last updated November 3, 2026 · https://www.certifyforce.com/study-guide/marketing-cloud-engagement-developer/api/rest-routes-for-journeys-sends-and-content*

Which REST route fits a task: firing a journey entry event, sending an Email Studio triggered send, sending through the Transactional Messaging API, texting through MobileConnect or editing a Content Builder asset, and when SOAP is still the right API.

- Certification: Salesforce Marketing Cloud Engagement Developer
- Exam section: API
- Study guide: https://www.certifyforce.com/study-guide/marketing-cloud-engagement-developer

**Official exam objective:**

> Given a scenario, describe API objects, methods, and routes.

## What the exam expects

- Build a journey entry event request: route, required properties, key rules and headers.
- Send an Email Studio triggered send through REST by ObjectID or external key, synchronously or not.
- Tell a Transactional Messaging API send definition from an Email Studio triggered send.
- Send a MobileConnect SMS to a number and know what must be true for it to arrive.
- Update Content Builder content through the asset API, and choose REST or SOAP for a requirement.
- Key terms: **entry event** (the journey entry source an API call fires); **EventDefinitionKey** (the event's unique ID from Event Administration); **triggered send definition** (an Email Studio definition a call sends on demand); **transactional send definition** (the Transactional Messaging API's own definition); **asset** (any Content Builder item: email, template, slot, image).

## Key facts

| Fact | Detail | Source |
|---|---|---|
| Entry event route | POST `/interaction/v1/events` | [Fire the Event](https://developer.salesforce.com/docs/marketing/marketing-cloud/references/mc_rest_interaction/postEvent.html) |
| EventDefinitionKey | From Event Administration; no period | [Fire the Event](https://developer.salesforce.com/docs/marketing/marketing-cloud/references/mc_rest_interaction/postEvent.html) |
| UTF-8 payloads | `Content-Type: application/json; charset=UTF-8` | [Fire the Event](https://developer.salesforce.com/docs/marketing/marketing-cloud/references/mc_rest_interaction/postEvent.html) |
| Triggered send by key | `key:` prefix in the path | [Triggered Send Definition](https://developer.salesforce.com/docs/marketing/marketing-cloud/references/mc_rest_messaging/messageDefinitionSends.html) |
| Triggered send RequestType | Default ASYNC; SYNC on request | [Triggered Send Definition](https://developer.salesforce.com/docs/marketing/marketing-cloud/references/mc_rest_messaging/messageDefinitionSends.html) |
| Transactional definitions | Transactional Send Journeys or the API, not Email Studio | [Transactional Messaging API](https://developer.salesforce.com/docs/marketing/marketing-cloud/guide/transactional-messaging-api.html) |
| SMS delivery | Only to Subscribed numbers for the short code | [Use the MobileConnect API](https://developer.salesforce.com/docs/marketing/marketing-cloud/guide/using-the-mobileconnect-api.html) |
| Asset update | PATCH `/asset/v1/content/assets/{id}` | [Use REST API Across MCE](https://trailhead.salesforce.com/content/learn/modules/marketing-cloud-apis/use-rest-api-across-marketing-cloud) |
| Classic Content | Retired April 24, 2023; SOAP routes still function | [Classic Content Retirement](https://help.salesforce.com/s/articleView?id=000352265&type=1) |
| REST request size | Up to 4 MB | [Use REST API Across MCE](https://trailhead.salesforce.com/content/learn/modules/marketing-cloud-apis/use-rest-api-across-marketing-cloud) |

## Check yourself

- What is the largest REST request body Marketing Cloud Engagement accepts?
- When does a REST call time out after 300 seconds instead of 120?
- Why can an older SOAP integration still reach classic emails after the Classic Content retirement?
- Which MobileConnect send method must an outbound message use before an API call can send it?

## Sources

- [Marketing Cloud Engagement Developer Exam Guide](https://help.salesforce.com/s/articleView?id=005298954&language=en_US&type=1)
- [Fire the Event](https://developer.salesforce.com/docs/marketing/marketing-cloud/references/mc_rest_interaction/postEvent.html)
- [Send a Message to a Triggered Send Definition](https://developer.salesforce.com/docs/marketing/marketing-cloud/references/mc_rest_messaging/messageDefinitionSends.html)
- [Transactional Messaging API](https://developer.salesforce.com/docs/marketing/marketing-cloud/guide/transactional-messaging-api.html)
- [Transactional Messaging API Quick Start](https://developer.salesforce.com/docs/marketing/marketing-cloud/guide/transactional-messaging-get-started.html)
- [Use the MobileConnect API](https://developer.salesforce.com/docs/marketing/marketing-cloud/guide/using-the-mobileconnect-api.html)
- [Content Builder API](https://developer.salesforce.com/docs/marketing/marketing-cloud/guide/content-api.html)
- [Use REST API Across Marketing Cloud Engagement (Trailhead)](https://trailhead.salesforce.com/content/learn/modules/marketing-cloud-apis/use-rest-api-across-marketing-cloud)
- [Get to Know Marketing Cloud Engagement APIs (Trailhead)](https://trailhead.salesforce.com/content/learn/modules/marketing-cloud-apis/get-to-know-marketing-cloud-apis)
- [Marketing Cloud - Classic Content Retirement](https://help.salesforce.com/s/articleView?id=000352265&type=1)

## About the full unit

The "Core concepts", "Exam traps" and "Worked scenario" sections of this unit, its 9 linked practice questions, and unlimited timed mock exams are included with the Marketing Cloud Engagement Developer pack (USD $19): https://www.certifyforce.com/practice-exams