Amazon Services
Amazon Marketplace Web Service (Amazon MWS) Documentation
Amazon MWS Documentation

Fulfilling Multi-Channel Fulfillment orders

The Fulfillment Outbound Shipment API section and the Feeds API section (using the FBA Shipment Injection Fulfillment Feed and the FBA Shipment Injection Cancellation Feed) have approximately equivalent functionality in terms of submitting and cancelling Multi-Channel Fulfillment orders. The Fulfillment Outbound Shipment API section has the advantage of being real-time, however, while the Feeds API section operates asynchronously.

For more information, see What you should know about the Fulfillment Outbound Shipment API section and What you should know about the Amazon MWS Reports API section.