In practice, MWS is gone and you should treat it as fully sunset. Amazon started phasing out MWS in stages and required all private developers to migrate to Selling Partner API (SP-API) by March 31, 2024, with access shut off from April 1, 2024. That means if anything in your stack still “works” on MWS today, it’s on borrowed time, unsupported, and could break without warning.
So yes, you need to migrate everything—orders, reports, inventory, FBA, feeds, finances, all of it—to their SP-API equivalents. The safe mindset in 2026 is:
No new development on MWS.
No strategic dependency on MWS.
Full SP-API adoption, including tokens, rate limits, and the newer endpoints Amazon is shipping only on SP-API.
If you’re still in “hybrid” mode, treat that as a short-term patch, not a stable architecture. The migration isn’t just about avoiding breakage, it’s also where you get access to newer inventory, capacity, and IPI-related data that MWS never exposed.
