# Choosing APIs for Commerce, Engagement and service

*B2C Solution Architect Study Guide · Integration · Last updated November 13, 2026 · https://www.certifyforce.com/study-guide/b2c-solution-architect/integration/choosing-apis-for-commerce-engagement-and-service*

Which API or protocol to use when integrating with B2C Commerce (SCAPI, OCAPI, WebDAV feeds and jobs), the Salesforce service org (platform events, Connect REST API, Order Management data) and Marketing Cloud Engagement (REST, SOAP, server-to-server auth and Event Notification Service), and the behaviours each one brings.

- Certification: Salesforce B2C Solution Architect
- Exam section: Integration
- Study guide: https://www.certifyforce.com/study-guide/b2c-solution-architect

**Official exam objective:**

> Understand the recommended methods on how to integrate systems to Agentforce Service, B2C Commerce, and Marketing Cloud environments using APIs and protocols that support various integration design patterns.

## What the exam expects

- Choose SCAPI for a new B2C Commerce build, use Shopper Context instead of hand-written hooks, and authenticate requests in an existing OCAPI integration correctly.
- Move feeds in and out of B2C Commerce with WebDAV, transfer scripts and job flows, with the right credential.
- Pick the Salesforce platform API for publishing events, reading CMS content and creating orders beside the B2C Commerce integration.
- Integrate with Marketing Cloud Engagement through REST and SOAP, server-to-server tokens and Event Notification Service.
- Route service-org email and web intake within their per-user and record-type rules.

Key terms:
- **SCAPI:** the B2C Commerce API, a set of stateless REST APIs introduced in 2020 for headless commerce.
- **OCAPI:** Open Commerce API, the older B2C Commerce API (Shop and Data APIs) in the platform since 2014.
- **WebDAV Impex share:** the instance's Impex/src folder that external systems upload feeds to.
- **Installed Packages:** the Engagement Setup page where an API integration gets its client ID and secret.
- **Event Notification Service (ENS):** an Engagement service that pushes events such as email unsubscribes to a registered HTTPS callback.

## Key facts

| Fact | Detail | Source |
|---|---|---|
| SLAS during migration | One token works across OCAPI and SCAPI | [Why SCAPI](https://developer.salesforce.com/docs/commerce/pwa-kit-managed-runtime/guide/why-use-scapi.html) |
| Easiest secure automated upload | HTTPS PUT to WebDAV Impex/src | [File Transfer](https://help.salesforce.com/s/articleView?id=cc.b2c_transferring_files_to_an_instance.htm&type=5&language=en_US) |
| FTPClient | Sandboxes only; firewall rule from Support | [Transfer Scripts](https://help.salesforce.com/s/articleView?id=cc.b2c_automating_file_transfer_through_scripts.htm&type=5&language=en_US) |
| Sibling flows | Run in parallel when resources allow | [Job Flows](https://help.salesforce.com/s/articleView?id=cc.b2c_job_flows.htm&type=5&language=en_US) |
| Platform event publish success | Request queued; published asynchronously | [Publish Events](https://developer.salesforce.com/docs/platform/platform-events/guide/platform-events-publish-api.html) |
| Delete change event (Pub/Sub API) | All fields present with empty values | [Change Event Body](https://developer.salesforce.com/docs/platform/change-data-capture/guide/cdc-event-fields-body.html) |
| Engagement token after integration change | Up to five minutes | [Server-to-Server](https://developer.salesforce.com/docs/marketing/marketing-cloud/guide/integration-s2s-client-credentials.html) |
| ENS delivery | At least once; nothing replayed for a paused period | [ENS](https://developer.salesforce.com/docs/marketing/marketing-cloud/guide/ens-get-started.html) |
| Emails one person can send | 250 per hour, each recipient counted | [Email-to-Case Limits](https://help.salesforce.com/s/articleView?id=service.email_to_case_limits_and_limitations.htm&type=5&language=en_US) |

## Check yourself

- In what order do sibling job flows run when they're configured to execute sequentially?
- Why can an FTP call from a B2C Commerce script run longer than the value passed to FTPClient.setTimeout?
- Which permissions does an Engagement API integration need before it can use Event Notification Service?
- When should a third party reach a private file-transfer pipeline through a public subpipeline?

## Sources

- [The Advantages of SCAPI](https://developer.salesforce.com/docs/commerce/pwa-kit-managed-runtime/guide/why-use-scapi.html)
- [Custom APIs (SCAPI)](https://developer.salesforce.com/docs/commerce/pwa-kit-managed-runtime/guide/custom-apis.html)
- [Get Started with OCAPI](https://developer.salesforce.com/docs/commerce/b2c-commerce/references/b2c-commerce-ocapi/get-started-with-ocapi.html)
- [Transferring Files to an Instance in B2C Commerce](https://help.salesforce.com/s/articleView?id=cc.b2c_transferring_files_to_an_instance.htm&type=5&language=en_US)
- [Automating File Transfer Through Scripts in B2C Commerce](https://help.salesforce.com/s/articleView?id=cc.b2c_automating_file_transfer_through_scripts.htm&type=5&language=en_US)
- [WebDAV Authentication and Authorization in B2C Commerce](https://help.salesforce.com/s/articleView?id=cc.b2c_webdav_authentication_and_authorization.htm&type=5&language=en_US)
- [B2C Commerce Job Flows](https://help.salesforce.com/s/articleView?id=cc.b2c_job_flows.htm&type=5&language=en_US)
- [Publish Event Messages with Salesforce APIs](https://developer.salesforce.com/docs/platform/platform-events/guide/platform-events-publish-api.html)
- [Which API Do I Use?](https://help.salesforce.com/s/articleView?id=platform.integrate_what_is_api.htm&type=5&language=en_US)
- [Importing Data When Using Salesforce B2C Commerce](https://developer.salesforce.com/docs/commerce/salesforce-order-management/guide/order-management-importing-data-using-b2c-commerce.html)
- [Change Event Body Fields](https://developer.salesforce.com/docs/platform/change-data-capture/guide/cdc-event-fields-body.html)
- [Server-to-Server Integrations with Client Credentials Grant Type](https://developer.salesforce.com/docs/marketing/marketing-cloud/guide/integration-s2s-client-credentials.html)
- [Marketing Cloud Engagement API References](https://developer.salesforce.com/docs/marketing/marketing-cloud/guide/apis-overview.html)
- [Get Started with Event Notification Service](https://developer.salesforce.com/docs/marketing/marketing-cloud/guide/ens-get-started.html)
- [Email-to-Case Limits and Limitations](https://help.salesforce.com/s/articleView?id=service.email_to_case_limits_and_limitations.htm&type=5&language=en_US)
- [Web-to-Case Guidelines and Limits](https://help.salesforce.com/s/articleView?id=service.customizesupport_web_to_case_notes.htm&type=5&language=en_US)

## About the full unit

The "Core concepts", "Exam traps" and "Worked scenario" sections of this unit, its 17 linked practice questions, and unlimited timed mock exams are included with the B2C Solution Architect pack (USD $19): https://www.certifyforce.com/practice-exams