Overview

Amazon has updated the Amazon Warehousing and Distribution (AWD) API to include a new parameter that tracks how many units are currently in transit from AWD storage to FBA fulfillment centers. This closes a significant visibility gap for sellers who use AWD as a lower-cost upstream storage layer, enabling more accurate inventory planning and reducing the risk of both stockouts and unnecessary overstocking.

What's New

• Replenishment quantity field — A new optional response parameter in the list inventory operation that reports units actively moving from AWD to FBA
• In-transit distinction — Sellers can now programmatically separate inventory sitting in AWD storage from inventory that is en route to FBA
• US marketplace only — The feature is currently available for the US marketplace, with no announced international rollout timeline
• Non-breaking change — The field is optional, so existing integrations will continue to function without modification

How AWD-to-FBA Replenishment Works

Amazon Warehousing and Distribution serves as a bulk storage layer that sits upstream of FBA. Sellers store larger quantities of inventory in AWD at reduced storage rates, and units transfer to FBA fulfillment centers when stock levels drop below certain thresholds. The replenishment cycle follows a predictable flow: inventory is held in AWD at lower cost, a trigger fires based on FBA inventory levels, units physically move from AWD to FBA, and those units become available for customer orders upon arrival.

Until this update, step three of that process was essentially invisible through the API. Sellers could query what was stored in AWD and what was available at FBA, but units moving between the two could not be tracked programmatically. This created a blind spot that complicated inventory management for any seller relying on automated tools or custom dashboards.

Why This Matters for Inventory Planning

The new replenishment quantity data addresses several practical pain points. Without in-transit visibility, sellers frequently initiated redundant transfers because they could not confirm that units were already on their way to FBA. This led to overstocking at fulfillment centers, which directly increases storage fees — particularly problematic during periods when Amazon enforces capacity limits or applies aged inventory surcharges.