The MergeCart parameter enables you to specify whether or not the contents of the remote cart should be added to the local cart when the customer opts to purchase the items in their cart. By default, the contents of the two carts are not mixed (MergeCart=False) and the customer is sent directly to the Order Pipeline to check out and purchase the items in their remote shopping cart.

When the value of MergeCart is set to True, the contents of the remote shopping cart are added to the customer's local shopping cart when the customer opts to purchase their items. Instead of going to the Order Pipeline, the customer is presented with a view of their Amazon.com shopping cart, which then contains the items that were in the remote shopping cart.

The MergeCart parameter is available only in the US locale.