Your inventory is wrong because it lives in several places at once

Short answer. Your inventory is never right because it lives in several places at once: your webshop, your marketplaces, your locations and your warehouse each keep their own count. Without a single leading source that updates everything in real time, every count drifts on its own and reality starts to diverge.

Inventory that does not add up is almost never a counting problem. It is a structural problem. The moment the same product is counted in more than one place, you get multiple truths about how much you have. The webshop thinks there are twelve, the store just sold three, and the warehouse physically holds nine. Nobody is lying. The system simply has no single place that alone determines the truth.

This is a universal pain because nearly every growing business eventually starts selling or storing in more than one place at once. You start with one webshop and one count in your head. Then bol.com gets added, then a physical store, then a second warehouse. Every expansion doubles the number of places where inventory is counted, and every place introduces delay. That delay is exactly where the gap sits between what your system says and what is actually in the box.

Why this comes up in so many businesses

The core is always the same: there is no leading source. In practice I see three ways this happens.

The first is multiple sales channels. You sell the same item through your own webshop and through marketplaces. When channel A sells something, channel B only finds out once someone passes it on manually or a synchronization runs. In that window you sell the same thing twice. That is called overselling, and it costs you a cancelled order plus a disappointed customer.

The second is multiple physical locations. Two locations and a warehouse, each with its own count. An employee cannot tell a customer whether the product is in the other store, because they only see their own inventory. You over-order in one place while it gathers dust in the other.

The third is the difference between booked and physical. Incoming deliveries that have not been booked in yet, returns that have not been processed, raw materials sitting in production. All of it inventory that exists somewhere but is right in no count at all.

In all three cases the solution is not to count harder. The solution is to designate one leading source and let everything around it update in real time. Automated synchronization that flows through immediately on every order is the only reliable way to keep this straight at scale, as suppliers of multichannel inventory software such as ChannelDock and Stockitup also confirm.

How this plays out in practice

The universal pain looks slightly different in each situation. Below are the concrete variants and where to find the worked-out approach for each case.

If you sell through multiple channels (e-commerce):

• Synchronizing inventory across channels: how to run your webshop, bol.com and other marketplaces from a single count so overselling disappears.

If you buy and resell (reseller):

• Tracking incoming packages: how to get a grip on what is on its way, so in-transit inventory counts in your picture instead of being a blind spot.
• When to reorder: how to get reorder advice based on actual sales velocity instead of gut feeling, so you neither run out nor build up dead capital.

If you work across multiple locations (wholesale):

• Inventory across multiple locations: how to get all locations and the warehouse into a single overview, including transfers between them, as TCOG on real-time location insight also describes.

If you manufacture yourself (production):

• Inventory and raw materials: how to track raw materials, semi-finished goods and finished products in a single chain, so you know what you can make and when a raw material runs out.

What all these situations share: the real work is not in choosing a tool, but in first thoroughly reviewing your process. Which steps that grew over time can be done smarter or removed entirely? Which count is leading and which are derived? Only once that is clear do you know whether an off-the-shelf package fits or whether I am better off building something custom that maps exactly onto your channels, locations and inventory logic. That trade-off, build versus buy, is where the difference lies between a count that is right and a dashboard that looks good but still lags behind.