Overview

Amazon has announced the final shutdown of the remaining Marketplace Web Service (MWS) API endpoints, with the deadline looming in the next few weeks. Sellers who rely on private, custom‑built applications to pull inbound, inventory, or outbound fulfillment data must transition to the newer Selling Partner API (SP‑API) or lose automated access to critical supply‑chain information.

Key Points

• MWS decommissioning — Amazon will permanently disable the last set of MWS endpoints that support inbound shipment creation, inventory level queries, and outbound fulfillment tracking, leaving no grace period after the cutoff date.
• SP‑API as the sole option — The Selling Partner API replaces MWS with OAuth‑based authentication, stricter rate limits, and fine‑grained permission scopes, meaning every existing private integration must be rebuilt or replaced.
• Impact on high‑volume sellers — A retailer managing 2,000 + SKUs and automating daily restock calculations will see its dashboards, alerts, and shipment‑creation scripts stop working the moment MWS goes dark.
• No extensions granted — Amazon has explicitly stated that the deadline is firm; requests for additional time or partial access will be denied.
• Third‑party alternatives — Sellers lacking in‑house development resources can opt for certified tools from Amazon’s Appstore that already support the required SP‑API functions, though subscription fees may apply.

What's Changing

1. Endpoint retirement — All calls to the MWS inbound shipment, inventory, and outbound shipment APIs will return HTTP 410 (Gone) after the shutdown date. For example, a script that previously used ListInventorySupply to update stock levels will receive an error response, halting the update cycle.
2. Authentication overhaul — SP‑API requires developers to obtain an LWA (Login with Amazon) access token and sign each request with AWS Signature 4. A private app that once sent a simple AWSAccessKeyId header must now implement the OAuth flow and manage token refresh cycles.