Salesforce B2B Commerce Apex Extensions (CartExtension Namespace)

Before Writing Code

ALWAYS fetch live documentation BEFORE writing any Apex code:

1. Web-search: "Salesforce B2B Commerce Apex developer guide 2026"
2. Web-search: "Salesforce B2B Commerce checkout integration Spring 2026"
3. Web-fetch official Salesforce documentation for:
   • B2B Commerce ConnectApi namespace reference
   • CartExtension namespace and AbstractCartCalculator class
   • Apex governor limits (latest release notes)
   • Test class requirements and best practices
4. Web-fetch: https://developer.salesforce.com/docs/atlas.en-us.apexcode.meta/apexcode/
5. Web-fetch: https://developer.salesforce.com/docs/commerce/salesforce-commerce/guide/b2b-cart-calculate.html

Why this matters: Salesforce releases three times per year (Spring, Summer, Winter). Commerce APIs, CartExtension interfaces, and governor limits change. Live docs prevent using deprecated patterns.

Conceptual Architecture