Overview

Amazon has fully retired its legacy Marketplace Web Service (MWS) as of March 31 2024, forcing every seller and developer to switch to the newer Selling Partner API (SP‑API). The change eliminates the old endpoints that powered countless third‑party tools, and sellers who haven’t completed the migration risk losing critical automation. Understanding the migration path, the functional upgrades, and the immediate actions required is essential for keeping inventory, orders, and reporting workflows alive.

Key Points

• MWS shutdown date — All MWS endpoints stopped responding on March 31 2024, ending the API that many custom integrations still rely on.
• Phased deprecation — Amazon first limited specific MWS sections on October 31 2023, then removed the remaining services three months later.
• SP‑API mandatory — The Selling Partner API is now the sole supported method for programmatic access to seller accounts, covering everything from listings to fulfillment.
• Authentication overhaul — SP‑API uses Login with Amazon and AWS Signature Version 4, replacing the simple key‑pair model of MWS and tightening security.
• Granular permissions — Sellers can now grant applications access only to the data and actions they need, rather than the all‑or‑nothing access required by MWS.
• Third‑party alternatives — Amazon’s Seller Central App Store lists vetted solutions for inventory, pricing, analytics, and order management, offering a shortcut for sellers without in‑house development resources.

How the Migration Works

1. Register as a developer — Log into Amazon Developer Central, create a developer profile, and obtain the required IAM credentials. Example: A seller who previously used a private MWS script signs up and receives an AWS Access Key and Secret Key.
2. Create a new SP‑API application — Within Developer Central, generate a new SP‑API app, assign the necessary scopes (e.g., listings, orders, reports), and note the client ID and client secret.