Update Cart Item

About

The updateCartItem mutation modifies the quantity or options of an existing cart item. Use this mutation to:

• Update product quantities in the shopping cart
• Adjust cart items from the cart page
• Modify product options or variants after adding
• Handle quantity increase/decrease operations
• Validate inventory availability for new quantities
• Recalculate cart totals and discounts

This mutation validates the new quantity against available inventory and updates cart totals including any applicable discounts and taxes.

Authentication

This mutation supports both authenticated customers and guest users:

• Authenticated customers: Provide a valid customer authentication token in the Authorization header. Obtain this token via the Customer Login API.
• Guest users: Provide the Guest Cart Token cartToken obtained from the Create Cart mutation.

Authorization: Bearer <accessToken>

Possible Returns

Field	Type	Description
createUpdateCartItem	Cart!	Updated cart with modified item.
updateCartItem	CartItem!	The updated cart.
message	String!	Success or error message.
success	Boolean!	Indicates successful update.
errors	[ErrorMessage!]	Validation errors if quantity unavailable.