Amazon Marketplace Web Service (MWS) will no longer be available after March 31, 2024. All MWS developers must migrate to Selling Partner API (SP-API) to avoid service disruptions. Refer to the Migration Hub for more information.
You can use the Reports API section or the Fulfillment Inventory API section to check your Fulfillment by Amazon (FBA) inventory availability regardless of whether you are selling on Amazon's website or through other retail channels.