Multichannel
Amazon inventory management
Amazon offers two places for stock to live: its own fulfilment centres under FBA, or your warehouse under Fulfilled by Merchant. With Multi-Channel Fulfilment, FBA stock can also fill orders from other channels, Shopify included.
On Amazon the stock can sit in two places at once: units in Amazon fulfilment centres and units on your own shelves. They form one product with two counts, and each channel needs to know which count it sells from.
Fulfilled by Amazon
Stock in Amazon's buildings
Products are sent to Amazon fulfilment centres across the UK and Europe, and Amazon picks, packs and ships them.
SourceFulfilled by Merchant
Stock in yours
Amazon: "Store, pack, and ship items that you prefer to fulfil yourself."
SourceMulti-Channel Fulfilment
FBA stock for other channels
Amazon: "Use your FBA inventory to fulfil customer orders from other sales channels—including your own."
SourceRead from Amazon's own seller pages on 23 September 2026. Marketplaces change their rules without notice, so check the current page before these inform a decision.
Three ways to run Amazon stock beside Shopify
Each is right for a particular operation. Listings, locations and order volume decide when you move from one to the next.
01
By hand in Amazon's own tools
Fits when
A few listings, one location, and someone who adjusts quantities as orders arrive.
Who owns what
Amazon and Shopify each hold their own count, and a person keeps them level.
02
A listing tool that pushes quantities
Fits when
Enough listings that hand edits fall behind, with stock still in one place.
Who owns what
One stock figure is pushed out to Shopify and Amazon, so a sale on one channel reduces the other.
03
A stock system that owns the truth
Fits when
Several channels, more than one location, or stock split between your shelves and Amazon's.
Who owns what
The stock system says what exists and where. Amazon and Shopify are told what they may sell, and orders flow back to be allocated.
How the stock systems in this market compare is on stock control software, and how orders from every channel get allocated is on order management systems.
The number Amazon should be sent
Stock is four numbers. A marketplace receives one of them, and it has to be the right one.
On hand
What sits physically on the shelf. Never the figure to send a marketplace.
Committed
Units already sold on any channel and not yet shipped. They leave the channel's figure the moment the order lands.
Available
On hand less committed, less any buffer held back for the channel. This is the figure the marketplace receives.
Incoming
Stock on order. Offered only where the marketplace allows a later dispatch date, and said so on the listing.
Shopify and Amazon on one stock figure
Tell us how many listings you run on Amazon, where the stock sits and what keeps the counts level today. We'll reply with the setup that fits and what it takes to get there.