Selling on Amazon is, at heart, a logistics problem
On Amazon Mexico, almost everything that decides whether you win the sale — showing up in the Buy Box (the default purchase box), qualifying for Prime, avoiding negative reviews for late delivery — comes down to how you fulfill. That's why a seller's first strategic decision isn't price: it's how they'll handle fulfillment.
Fulfillment is the full process from the moment an order comes in until it reaches the customer's door: storing, picking, packing and shipping. On Amazon you solve it with one of two models — or a mix of both.
FBA vs. FBM: the two models
| Model | Who stores and ships | What you gain | What you give up |
|---|---|---|---|
| FBA | Amazon (in its centers) | Automatic Prime, easier Buy Box | Inventory control + storage fees |
| FBM | You (or your operator) | Full control, no Amazon storage fees | You own the speed and the compliance |
- FBA (Fulfillment by Amazon): you send your inventory to Amazon's centers; they store, pack and ship. You get the Prime badge automatically and compete better for the Buy Box. The cost: you pay handling and storage fees — which spike with aged inventory (product sitting for months) and a low IPI (the index Amazon uses to score how healthy your inventory is).
- FBM (Fulfillment by Merchant): you store and ship each order yourself — directly or through a logistics operator. You keep full control of inventory and packaging, and avoid Amazon's storage fees. In exchange, punctuality is on you: ship late and your account feels it.
One key point: with FBM you can also qualify for Prime (so-called Seller-Fulfilled Prime) if you meet Amazon's shipping metrics. In other words, you don't need FBA to have Prime — you need an operation that meets the SLA (the committed delivery time).
Where a logistics operator (3PL) fits in
A 3PL (external operator, third-party logistics) works both models, but does different things:
- For FBA, the operator handles the prep: it receives your import, labels each unit with its FNSKU (the barcode Amazon requires to identify your product), poly-bags or packs it to spec, builds the boxes with their box content (the detail of what each box holds) and ships them to the right center. If that prep fails, Amazon rejects the shipment. That work is marketplace prep.
- For FBM, the operator is your fulfillment: it stores inventory, builds each order and ships it within the promised time. That's the fulfillment service with multi-carrier shipping.
With a single operator you run one inventory for both models: what you send to FBA and what you dispatch via FBM leave the same warehouse — no duplicated stock or systems.
FBA or FBM? How to decide
- FBA makes sense for high-rotation products, standard size and weight, where you want Prime without operating logistics and the margin absorbs Amazon's fees.
- FBM makes sense for a broad, heavy, bulky or slow-moving catalog (where FBA storage fees eat your margin), when you want to control the delivery experience, or when you sell across several channels — your own store, Mercado Libre — and prefer not to trap stock in a single marketplace.
- The hybrid strategy usually wins: your best-sellers on FBA for Prime and speed, and the rest of the catalog via FBM with a 3PL to protect margin.
Frequently asked questions
What's the difference between FBA and FBM?
In FBA, Amazon stores and ships your product from its centers; in FBM, you (or your logistics operator) do. FBA gives you automatic Prime but charges storage; FBM gives you control and avoids those fees, in exchange for owning punctuality.
Can I have Prime without using FBA?
Yes. With Seller-Fulfilled Prime you can show the Prime badge while shipping yourself (or via a 3PL), as long as you meet Amazon's speed and compliance metrics.
What is FBA prep and why does it matter?
It's getting your inventory ready to Amazon's specs: FNSKU label, correct packaging, declared box content. If anything is off, Amazon rejects the shipment and you lose weeks. That's why many sellers delegate it to a marketplace prep operator.
Can I sell on Amazon and Mercado Libre with the same inventory?
Yes, if your operator centralizes stock. It's the same principle we cover in Fulfillment for Mercado Libre: one inventory, several channels.
Selling on Amazon and the fees or timings are squeezing you? See Ecommex's fulfillment service for FBM, or our marketplace prep if you run FBA — one inventory for Amazon, Mercado Libre and your store.