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Cart Basics

This document explains the fundamental concepts of cart management in Elastic Path Commerce Cloud.

Cart Data Model​

The cart system consists of two primary entities:

  • Cart - The parent container for all items a customer wants to purchase
  • Cart Line - Individual product items within the cart, represented as cart_item objects

Each cart has the following key attributes:

  • Unique ID for identification
  • Relationships to items (products)
  • Optional customer association
  • Currency and pricing information
  • Meta data including display pricing

ID Conventions​

Cart IDs are unique identifiers that are used to retrieve and manipulate cart data:

// Example cart ID structure
"cart_id": "12345678-1234-1234-1234-123456789012"

Cart IDs are typically stored in localStorage or cookies for persistence across page reloads and sessions.

Anonymous Carts​

Anonymous carts allow visitors to shop before signing in. Key features include:

  • Created without requiring user authentication
  • Can be merged with a user's cart upon login
  • Persist based on browser storage mechanisms
  • Retrieved using the getCart SDK method with the cart ID

Merge Rules​

When a user logs in with an existing anonymous cart, the following merge rules apply:

  • Carts must share the same currency and store to be eligible for merging
  • When currencies match, items from the anonymous cart are added to the user's cart
  • Line items with the same product are typically combined and quantities summed
  • Promotions are re-evaluated after merging

Key Considerations for Architects​

  • Design your cart state management to persist cart IDs between sessions
  • Implement cart recovery strategies for abandoned carts
  • Create intuitive cart merge behaviors for a seamless shopping experience
  • Plan for inventory validation at key cart touchpoints
tip

For a complete implementation example demonstrating these cart concepts, check out the SPA Cart Example on GitHub.