Amazon FBA vs FBM, which fulfilment model to pick

Amazon FBA vs FBM, two fulfilment models

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.

What Amazon FBA is, and who it pays off for

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:

• Light, small, fast-moving products. FBA fees rise with weight and size, so a small range with good turnover is the most profitable here.
• Selling abroad. If you want to sell into Germany, France or Italy, Amazon's warehouses and cross-border delivery programme spare you building international logistics of your own.
• No warehouse of your own. With no warehouse, no packing staff and no carrier contracts, FBA lets you start without those investments.

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.

What Amazon FBM is, and when it wins

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:

• Heavy and bulky products. Furniture, appliances or high-volume goods generate steep FBA fees that FBM avoids.
• Low margin or slow turnover. When goods sit for a while, FBA storage fees can eat the profit, and your own warehouse is cheaper.
• You already run working logistics. If you serve your own store and Allegro, and you have a warehouse, carrier integrations and a packing process, adding Amazon on FBM is a natural step.
• Brand control matters to you. Your own packaging, inserts and full control over customer service build an image FBA does not give you.

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.

Amazon FBA vs FBM, side by side

The table below shows the differences that matter most from a seller's point of view.

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 hybrid model, when to combine FBA and FBM

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.

Managing Amazon selling whichever model you pick

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:

• One order view. Orders from Amazon (FBA and FBM), Allegro and your own store land in a shared list, so none of them slips through.
• Automatic invoices. After an order, NavyFlame issues an invoice in your accounting system with no retyping. You set it up once, as an order to invoice automation.
• Stock kept in step. A sale on one channel lowers the level on the others, which protects you from overselling in a hybrid or multi-channel setup.
• Labels and despatch for FBM. When you fulfil yourself, you generate carrier labels and track parcels from the same place you handle orders.

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.

The hidden costs worth remembering

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.

In summary, which model to pick

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.