Integration · Multi-channel sync

You have 50 in stock. Three channels are each selling 50.

Sell on Shopify, Amazon and eBay and each one keeps its own count, so the same unit gets sold more than once. A sync tool is the obvious answer, and most sellers buy one and still oversell. The accuracy is not in the subscription. It is in the setup underneath it.

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What it looks like

You only notice when an order you cannot fill comes in.

On the surface everything is selling. The problem stays hidden until two orders arrive for one unit, and then it is your team that has to clean it up.

A burst of sales on one channel clears the shelf, but the others keep showing the item available and keep taking orders.

You cancel, refund and apologise, and on a marketplace each cancellation chips away at the account health that lets you sell there.

To stay safe you hold a buffer back on every channel, which means stock you own but deliberately do not sell.

Or, before any tool, you are updating each channel by hand after every sale, which eats the time you should be spending selling.

You bought a sync tool, and it still happens, because the same product has a different code on each channel, or a bundle never told the system which parts to subtract.

So you are firefighting refunds instead of selling, and quietly rationing your own stock to stay out of trouble. The tool was supposed to fix this. The reason it did not is underneath it.

Why it happens

A sync tool moves numbers. It cannot fix the data they are built on.

Most overselling across channels comes down to a handful of causes, and most of them sit below whatever tool you have connected.

Each channel keeps its own stock count, and unless they all draw from one shared figure, they drift apart between updates.

Sync is never quite instant. Some tools update only every half hour or so, and a busy spell is all it takes to sell the same unit twice.

The same product carries a different code on each channel, so the tool cannot tell the listings are the same item and keeps separate counts.

Bundles and kits are not mapped to the parts they contain, so selling a bundle never reduces the components, and the components oversell.

Returns and cancellations do not flow back into the available count, so stock you have again is still showing as gone.

Stock can also sit in more than one place, your own shelves and a fulfilment centre like Amazon's, and if those pools are not kept distinct, one channel can quietly commit another channel's stock.

None of that is fixed by the subscription. It is fixed by the setup underneath it: clean codes, mapped bundles, one shared count, returns flowing back. The quickest way to see which of these is costing you is to look at your channels together. That is what a 30-minute review is for.

What good looks like

One count every channel reads, and a tool that finally holds.

Every channel draws from one shared stock figure, so a sale anywhere drops the count everywhere before the next order lands.

Product codes are aligned across channels, and bundles know their parts, so the sync has clean data to work with.

Returns and cancellations flow back into the count, so stock you have again is on sale again.

A small, deliberate buffer covers the seconds of real lag, instead of you holding stock back blind on every channel.

Your standing on each marketplace is protected, because the cancellations that threaten it stop happening.

Orders from every channel land in one place to be picked and shipped, and you can see what is really in stock across all of them at a glance.

Because we are vendor-neutral, we are not here to sell you Linnworks over Cin7, or Sellbrite over Veeqo. We fit the right tool to your channels, or connect what you have, and we fix the data underneath so it actually holds. And for most sellers this is a sync layer, not a new ERP. You build it once, and use it everywhere.

Common questions

Multi-channel stock, answered.

Because each channel keeps its own stock count, and unless they all draw from one shared figure they drift apart between updates. A sale on one clears the shelf while the others keep selling. Most sellers add a sync tool and still oversell, usually because the same product has a different code on each channel, or a bundle was never mapped to its parts. The fix is one shared count with clean data beneath it, not just the tool.
Close to it, but not to the millisecond. A good setup updates every channel within seconds of a sale, which is enough for almost everyone. For the small gap that remains, a modest buffer on fast-moving lines covers you, rather than holding stock back blindly on every channel. Anyone promising perfectly instant sync across marketplaces is overstating it.
It can. On Amazon, seller-fulfilled cancellations feed a cancellation-rate metric that has to stay below a set threshold, and breaching it can deactivate your offers. eBay and other marketplaces penalise repeated cancellations with lower visibility, warnings and, eventually, suspension. So accurate stock is not just about refunds, it protects your right to keep selling on the channel.
Shopify's native marketplace sync handles the basics for a small catalogue on a couple of channels. As you add channels, bundles, multiple locations or real volume, it leaves gaps, and a dedicated tool such as Linnworks, Cin7, Sellbrite or Veeqo fits better. We are vendor-neutral, so we match the tool to your channels rather than push one, and if the native sync is genuinely enough, we will say so.
Because a bundle is several products sold as one, and unless the system knows which components it contains, selling the bundle never reduces those components' stock. They then oversell on every channel that lists them separately. Mapping each bundle to its parts, so a sale subtracts the right components, is one of the most common fixes we make.

In short

  • Overselling across Shopify, Amazon and eBay happens because each channel keeps its own stock count and they drift apart unless all of them draw from one shared figure.
  • A sync tool on its own does not stop overselling; accurate multi-channel stock depends on the setup underneath it, aligned product codes, mapped bundles, and returns flowing back into the count.
  • Sync is never perfectly instant, so a small buffer on fast-moving lines covers the brief lag, which is more efficient than holding stock back blindly on every channel.
  • On marketplaces, overselling drives cancellations that damage account health, and on Amazon a seller-fulfilled cancellation rate above the allowed threshold can deactivate listings.
  • MYT Digital is vendor-neutral across tools such as Linnworks, Cin7, Sellbrite and Veeqo, fitting or connecting the right one and fixing the data beneath it, which for most sellers is a sync layer rather than a new ERP.

Stop selling what you do not have

See why your channels keep overselling, and what makes it stop.

Book a 30-minute review and we will look at your channels together, show you where the counts drift, and what it takes to make one count hold across all of them.

Book a 30-minute review See what it is costing you