fabric's Cart APIs let you add, update, and remove items from your Storefront cart, either as a guest user or as a logged-in user. It also provides functionality to merge carts when you switch from guest user to logged-in user, to apply coupon codes and other attributes (for example, gift wrapping) to the cart items. Additionally, it supports more advanced use cases such as using multiple carts within a B2B organization and sharing of carts, as well as supporting a unified cart experience for multi-region and multi-brand businesses.

These APIs provide high performance, scalability, multi-tenancy, and configurability to the end-to-end order processing actions that start from an item being added to the cart, through the pre-checkout stage that includes billing, shipping, and payment details, to the checkout stage where the order is processed and confirmed by the fabric Order Management System (OMS) or alternatively an Order Draft can be created. An order draft can be used to coordinate the creation of an order in any other downstream systems.