Like shopper profiles, commerce items and orders, promotions include a predefined set of properties. Promotion properties are determined by an item type.

Promotions use the /itemTypes/{id} administration endpoint, where the ID is a repository item type that supports customizable properties. When you use PUT with the endpoint, the endpoint uses attributes whose names are configured for each item type. In the case of custom properties for promotions, the itemType is promotion.

You cannot create additional item types, but you can add custom properties to the promotion item type. For example, you could add a campaign custom property that an administrator uses to indicate additional promotion details.