Abstract: Techniques and system configurations for order tracking and delivery fulfillment in an electronic commerce setting is described herein. In one example, a shipment that originates from a distribution center of a retailer is identified for delay (e.g., a delayed shipment in transit via a national carrier). The delayed shipment is replaced with a substitute shipment from inventory at an in-store location of the retailer. The substitute shipment is selected from an in-store location of the retailer based on proximity to the shipping destination, and is delivered via courier or agent to meet or precede a promised delivery date. The delayed shipment is then intercepted or redirected to the shipping source, the in-store location, or a distribution center. Related techniques for the management, processing, and tracking of data and information associated with substitute shipments are further described herein.