Commerce extensions versus the checkout integrations framework
Key Takeaway
A webstore can use extensions or integrations, but not both. Salesforce recommends extensions, and an integration runs only when the Cart Calculate API is off.
Salesforce Commerce offers two Apex-based ways to plug custom logic or third-party services into cart and checkout: the older checkout integrations framework and Commerce extensions, introduced in Winter '24. The two differ in how you write the class, what the class can change and how you set it up. Your choice also decides whether the Cart Calculate API can stay on.
How integrations and extensions differ
The checkout integrations framework provides checkout integration points to third-party services. Commerce extensions use Apex to customize the functionality behind B2B and B2C storefronts.
| Integrations | Extensions | |
|---|---|---|
| Coding approach | Your class implements an Apex interface | Your extension provider extends an Apex base class |
| Customization | Replaces the default calculation for its area and can't build on top of it | Extends or replaces default behavior, depending on the extension type |
| Commerce domains | Only the 4 checkout calculators | 5 cart and checkout calculators, the pricing service and other services |
Salesforce recommends extensions over integrations for two reasons: extensions allow more targeted customizations, and they cover more commerce domains. Integrations remain fully supported.