Amazon Marketplace Web Service (MWS) will no longer be available after March 31, 2024. All MWS developers must migrate to Selling Partner API (SP-API) to avoid service disruptions. Refer to the Migration Hub for more information.
Amazon recommends that you create listings for all of the items that you want to include in an inbound shipment plan before calling the CreateInboundShipmentPlan operation. After you have created listings for the items that you want to include in the CreateInboundShipmentPlan operation, include only the SellerSKU and Quantity request parameters when calling the operation. Do not include the ASIN or Condition request parameters.
For more information, see Shipping inventory to Amazon's fulfillment network.