FBA hands your warehouse and shipping to Amazon, FBM keeps them on your side. Here is how the two differ in cost and control, and how to keep orders, stock and invoices in one place either way.
Selling on Amazon starts with a decision that shapes costs, margin and daily work: who fulfils the order. Amazon offers two models. FBA (Fulfillment by Amazon) moves the whole warehouse and logistics to Amazon, while FBM (Fulfillment by Merchant, also known as MFN) leaves them with the seller. The choice is not permanent, you can switch and you can combine the two, but the consequences are worth understanding before you send the first pallet to a fulfilment centre.
This guide compares FBA and FBM on cost, control and requirements, and closes with how to manage orders and invoices whichever model you pick.
Under FBA you ship your goods to an Amazon warehouse. From that point Amazon stores the products, packs them once an order comes in, despatches parcels, handles returns and looks after delivery-related customer service. Your listings automatically gain the Prime badge, which lifts conversion and visibility in Amazon search.
FBA pays off in a few situations in particular:
The price of that convenience is fees: a fulfilment fee and a storage fee, which climbs for goods that sit still. You also give up some control over what the parcel looks like and how contact with the customer goes.
Under FBM (Fulfillment by Merchant) you store the goods and fulfil every order yourself. Amazon is a sales channel, but the warehouse, the packing, the carriers and the returns stay in your hands. You pay no FBA fulfilment or storage fees, and in exchange you carry the whole logistics operation.
FBM wins in cases like these:
The downside of FBM is that the seller answers for despatch times and quality metrics. Amazon watches punctuality closely, and weak results push listings down. That is why a capable order management system matters so much under FBM.
The table below shows the differences that matter most from a seller's point of view.
| Criterion | FBA (Fulfillment by Amazon) | FBM (Fulfillment by Merchant) |
|---|---|---|
| Warehouse and shipping | Amazon's side | Seller's side |
| Prime badge | Automatic | Only via Seller Fulfilled Prime, with quality requirements |
| Fees | Fulfilment fee plus storage | No FBA fees, your own logistics costs |
| Control over the parcel | Limited | Full: packaging, inserts, carrier |
| Best for | Light, fast-moving goods, selling abroad | Heavy, low-margin goods, own facilities |
| Returns handling | Amazon | Seller |
| Responsibility for deadlines | Amazon | Seller, via quality metrics |
| Invoicing | Seller | Seller |
One line is worth noticing: the duty to issue invoices sits with the seller in both models. Amazon does not take the bookkeeping off your hands, whoever packs the boxes.
The answer is rarely FBA alone or FBM alone. Many experienced sellers run a hybrid: bestsellers and light products go to FBA for Prime and fast delivery, while heavy, niche or seasonal goods stay in FBM where costs are lower. That split lets you optimise margin line by line.
The hybrid model has one condition, though: consistent stock. If the same product sells on FBM through Amazon, on Allegro and in your own store, and each channel holds a separate, unsynchronised level, sooner or later you will sell something that is gone. Overselling on Amazon is not just a cancelled order, it also drags your account metrics down. That is why, across several channels, central warehouse management stops being a convenience and becomes a requirement.
The choice between FBA and FBM is about logistics, but you have to control orders, invoices and stock either way. This is where an e-commerce hub comes in. NavyFlame ties the Amazon integration to your other sales channels and to your invoicing system, so all selling flows into one panel.
In practice that means several things:
Put differently: FBA and FBM decide who packs the box, and NavyFlame makes sure the order, the invoice and the stock level always agree. Under FBM that layer is close to essential, because the deadlines are yours; under FBA it puts your bookkeeping and sales data in order.
Comparing FBA and FBM, it is easy to focus on visible fees and miss the hidden ones. In FBA those are long-term storage fees on goods that sit, plus the cost of removing or disposing of stock that will not sell. Pick the wrong range and FBA can turn a profitable product into a loss-making one.
In FBM the hidden costs are time and labour: packing, handling returns, answering customer messages and watching despatch deadlines. Do that by hand and, at scale, you need either people or automation. So the profitability of either model should count not just Amazon's commissions but the real cost of your time. Automating the FBM side, invoicing, stock sync and despatch, moves that model's break-even point down noticeably.
There is no single right answer, only a fit to the product and the scale. Pick FBA when you sell light, fast-moving goods, aim at foreign markets and want Prime without building logistics. Pick FBM when your products are heavy or low margin, when you already have a working warehouse with carrier integrations, or when full brand control matters. In practice the hybrid model, chosen line by line, usually wins.
Whatever you pick, look after the layer that does not depend on the fulfilment model: consistent orders, invoices and stock in one place. That is what NavyFlame does as an e-commerce hub. Before you decide, click through the interactive demo, with no sign-up and no card.
FBA (Fulfillment by Amazon) means you ship your goods to an Amazon warehouse and Amazon handles storage, packing, despatch and returns. FBM (Fulfillment by Merchant) means you store the goods and fulfil every order yourself, with your own carriers. With FBA you pay for Amazon's convenience and logistics; with FBM you keep full control and lower per-unit fees, but you carry the whole operation.
It depends on the product and the scale. FBA suits light, fast-moving goods and selling abroad, because it gives you Prime and fast delivery without building your own logistics. FBM is cheaper for heavy, bulky, slow-moving or low-margin products, and when you already run a working warehouse with carrier integrations. Many sellers combine both.
Yes, with FBM you are responsible for fulfilment and for the sales documents. You can automate it, though: NavyFlame pulls Amazon orders and issues invoices in your invoicing system (wFirma, inFakt, Fakturownia, iFirma) with no retyping. With FBA the invoicing duty also sits with you, so automation is worth having in both models.
Yes. Amazon lets you run part of your range in FBA and part in FBM on the same seller account. It is a common strategy: bestsellers and light products go to FBA for Prime access, while heavy or niche goods stay in FBM. What matters then is keeping stock consistent, so you never oversell.
Overselling threatens when the same goods sell on Amazon, on Allegro and in your own store from separate, unsynchronised stock. The answer is one central warehouse that updates availability on every channel after each sale. NavyFlame acts as that hub and takes the stock down across all platforms at once.
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Whether you pick FBA, FBM or both, keep orders, stock and invoices in one place. Start with the full demo, no sign-up and no card.
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