This offers some great insight into Amazon’s ecosystem
An example of this would be if Hydro Flask operated their own separate e-commerce store on Shopify — when a customer places an order on the Shopify store, Hydro Flask can send the order to FBA (you guessed it — via an external API) and FBA will ship it directly to the customer.
The benefit for Hydro Flask is obvious. They can have the product manufactured in China, and use a freight forwarder like Flexport to ship the product directly from the factory to Amazon’s warehouse — and thus avoid the headache (and overhead) of operating their own warehouse. For Amazon, the surface benefits are numerous: a) better utilization of excess capacity, b) increased shipping volume / leverage with UPS/FedEx, and c) revenue from the fulfillment services (which, combined with Marketplace commissions and “other third-party seller services,” totaled a whopping $6.4 billion in Q1 2017 — or 25 percent of Amazon’s total revenue).
Why Amazon is eating the world
by Zack Kanter