Overview

In April 2022 Amazon launched a new generation of its Selling Partner API (SP‑API), retiring many of the long‑standing MWS endpoints that sellers and third‑party developers have relied on for years. The upgrade brings OAuth 2.0 authentication, richer data structures, and stricter throttling rules, meaning that anyone still using the legacy MWS calls must migrate quickly to avoid service interruptions. Sellers who fail to transition before the September 30 2022 deadline risk losing access to order, inventory, and financial data essential for daily operations.

Key Points

• Unified OAuth 2.0 login — The SP‑API now authenticates exclusively with Login with Amazon (LWA) tokens, so merchants no longer need to manage separate AWS access keys for each marketplace, a relief for operators handling dozens of accounts.
• Expanded payloads — Endpoints such as GET /orders/v0/orders return nested shipment‑tracking events, line‑item tax breakdowns, and item‑level fee details that were unavailable in the older MWS responses, enabling finer‑grained analytics.
• Per‑resource throttling — Amazon enforces a rolling‑second limit on each API resource (for example, 10 calls per second for ListingsItems), and includes Retry‑After guidance when the limit is exceeded, forcing integrations to implement back‑off logic.
• Standardized error schema — All error responses now contain a structured errors array with a machine‑readable code, a human‑friendly message, and optional details, allowing developers to differentiate transient network glitches from permanent permission issues.
• Hard migration deadline — Amazon has set September 30 2022 as the final cut‑off; after that date any request to a legacy MWS endpoint returns a 404 error, making the SP‑API the sole gateway for marketplace data.
• Sandbox‑first testing — The updated platform provides a dedicated sandbox environment that mirrors production rate limits and data models, encouraging sellers to validate their code before going live.