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eMAG and Allegro from one warehouse: serve marketplaces without overselling

Dávid Kornis, Head of Fulfillment Division · Published: November 10, 2026 · 5 min read

In short
  1. If you sell on several channels, the biggest risk is overselling: selling something that's no longer on the shelf.
  2. There are three ways to go: your own warehouse, the marketplace's own warehouse, or a fulfillment partner with one shared stock.
  3. Before you switch on your second marketplace, make sure you have real-time stock sync and a dispatch cut-off you can keep.

Allegro launched in Hungary in October 2024, so alongside eMAG there are now two major marketplaces to choose from. Many online stores start selling on both, and that's where the first real warehouse question comes up: how do you keep your stock in order when the same product sells in three places?

What is overselling, and why is it costly on a marketplace?

Overselling happens when you sell the same item on two channels because stock didn't update in time. In your online store, that means an awkward email to the customer. On a marketplace, it turns into a canceled order, and marketplaces monitor seller performance: cancellations and late dispatches can hurt your seller rating and visibility.

The more channels you sell on, the higher the risk. With one online store and one marketplace, you can still track stock by hand; with a third channel, hardly.

Three ways to sell on several marketplaces

If you sell on eMAG and Allegro alongside your online store, you can handle the warehouse side in three ways.

Three ways to sell on multiple channels
AspectOwn warehouseThe marketplace's warehouseFulfillment partner with shared stock
StockOne stock, but you update it on every channel.Separate stock for each channel.One stock, with automatic sync.
ChannelsAny, but you have to serve them all yourself.Only that one marketplace.Online store, marketplaces and B2B (wholesalers, resellers, retail chains).
WorkYou pack and ship.The marketplace packs, but only its own orders.The partner packs for every channel.
OversellingHigh if you update by hand.Low, but your stock gets fragmented.Low, because every channel sells from one stock.

Some marketplaces offer their own warehousing service. It's convenient, but goods you send there only sell on that one marketplace, and you have to serve your online store and other channels from somewhere else.

How does shared stock work?

With shared stock, every channel, your online store, eMAG and Allegro alike, sells from the same warehouse stock. When an order comes in on any of them, the warehouse system reserves the item and updates the available quantity on the other channels too. That way, the same item can't be sold twice.

  1. The order reaches the warehouse automatically from the marketplace or your online store.
  2. The warehouse system reserves the stock.
  3. The available quantity updates on the other channels too.
  4. We ship the parcel before the carrier's cut-off.

Shared stock works across borders too: we ship orders from eMAG Romania and Bulgaria, and from Allegro Poland, Czechia and Slovakia, from the same stock with export carriers. On foreign marketplaces too

You can try it on a sample: on the marketplace fulfillment page, you can buy on three channels from the same stock.

What to watch out for on a marketplace

Dispatch deadline

The marketplace sets how much time you have to ship an order. Choose a warehouse operation that can keep to it at peak times too. With us, orders received on working days up to 20:00 (Budapest time), depending on the carrier, still ship the same day. About dispatch times

Stock updates

Stock needs to update on every channel in real time, not once a day from a spreadsheet. The less often it updates, the higher the risk of overselling. With us, stock sync is real-time, with ready-made integrations for eMAG and Allegro.

Returns

Think through where marketplace returns arrive and how they get back into sellable stock. If a returned item sits for days, you can't sell it on your other channels either. About returns management

Checklist before your second marketplace

  1. Every product has a unique SKU and barcode.
  2. Your stock is recorded in one place, not per channel.
  3. Stock updates automatically on every channel.
  4. You can keep the marketplace's dispatch deadline at peak times too.
  5. You know where returns arrive and how they get back into stock.
  6. Someone checks cancellations and delays every day.

If several of these are missing, a second marketplace will bring more work than revenue. That's when it's worth outsourcing your warehouse. We wrote about when it pays off in a separate article. If you're already there: this is how we fulfill eMAG and Allegro orders.

Frequently asked questions

Got another question? Write to us.

What is overselling?

It's when you sell the same item on several channels because stock didn't update in time. On a marketplace, it turns into a canceled order, which can hurt your seller rating.

Can I sell from one stock in my online store, on eMAG and on Allegro?

Yes, with shared stock: every channel sells from the same warehouse stock, and when an item sells on one, the others update too. We have ready-made integrations for both eMAG and Allegro.

When does it make sense to choose a fulfillment partner for marketplaces?

When you sell on several channels and packing or stock tracking already takes up a lot of time. From roughly 50 orders a month, it's worth talking to us.

What's the difference between a marketplace's warehouse and a fulfillment partner?

Only that marketplace's orders ship from the marketplace's warehouse. A fulfillment partner serves every channel, your online store and the marketplaces alike, from one stock.

How quickly can marketplace fulfillment start?

In about 10 working days, if your product data arrives in the first two days and your goods by working day 3. We have ready-made integrations for eMAG and Allegro, and we handle the setup. Onboarding day by day

About the author

Dávid Kornis is Head of Fulfillment Division at MDS e Fulfillment. He is responsible for the entire fulfillment operation, from the warehouse to the services. He also spoke to Trade magazin about HGL Group's e-fulfillment direction: Replanned routes. Dávid Kornis on LinkedIn

Sell in more places. From one warehouse.

Tell us where you sell now and where you'd like to sell. We handle the setup.

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