Amazon's Subscriptions API, specifically the Any Offer Changed notification, is the feed sent by Amazon where our system obtains information regarding the various offers for each listing on Amazon's website. This Any Offer Changed notification provides various pieces of information for each offer on the listing such as:
Current Buy Box winner
Fulfillment Type including Fulfilled by Amazon (FBA), Seller Fulfilled Prime (SFP), or Merchant Fulfilled (MFN)
Featured merchant status
Item condition
Shipping price and time
Seller feedback rating
Availability including in stock or backordered
Ship from location
It is important to note that Amazon will only send the Top 20 offers in the Any Offer Changed (offer report) provided by their Subscription API. This is typically the first two pages of offers on Amazon's website.