Online store and stock sync: why quantities drift

A customer paid for an item online and emailed to ask where it is. There's an empty space on the shelf, because the last one was sold at the till yesterday. Now you have to apologise, refund the money, and the customer is probably gone.

Short answer: stock levels drift because two systems keep the same number in different places and update each other after the fact. An integration can be improved, but the time lag and the point of failure remain. The problem only disappears completely when the online store and the till use the same database.

Five common causes

1. Time lag. Many integrations update quantities on a schedule. When the last item is sold at the till, a short window remains in the online store when the same product can still be bought.

2. Different SKUs. If the code is SH-100 in one system and SH100 in the other, the integration can't find the product. Often it doesn't report this anywhere.

3. Variants. The main product is found, but size M and size L are linked incorrectly. The total quantity looks right, but a specific size is out of stock.

4. The integration stops. A key expired, a module was updated or a service was briefly down. You usually only notice when a product's stock level is already wrong.

5. Reservation. An unpaid order may not hold the goods. A customer is paying at their bank while someone else sells the last item at the till.

How to improve your existing setup

If you stay with two systems, these steps make things better:

• Choose one main system. The quantity changes in one place, the other only reads it.
• Tidy up the codes. Every product and variant must have one unique SKU, preferably an EAN code too.
• Add a buffer. Show a product as out of stock online when only one or two are left.
• Set up an alert. When the integration fails, someone has to get a notification.
• Compare regularly. A small stocktake once a week of your fastest-moving products reveals errors early.

These help, but the work and the point of failure remain.

What changes when there is one database

NUNDINAE doesn't sync the online store and the stock, because they are one application. There is one stock figure, and all sales channels use it:

• A till sale takes the goods out of stock immediately. The same moment applies in the online store.
• An online order sets the goods aside as soon as payment starts.
• An unpaid order expires after a set time (60 minutes by default) and the goods are released on their own.
• A cancelled order returns the goods to stock.
• Receiving goods with a barcode scanner makes the product available online immediately.
• Materials used on a service come out of stock when the service is marked as completed.

Every change is in the stock movement history with the reason and who made it. If a stock level looks wrong, you can see who changed it and why.

The available quantity isn't just the number on the shelf. The system subtracts reserved goods and, if you wish, a safety stock. That way you see on the dashboard in good time what needs ordering, and you can put together a supplier order sheet.

When syncing is perfectly fine

One database isn't always necessary. If you only sell online, or you have plenty of goods and selling the last item is rare, a well-configured integration works satisfactorily. It may also not be the first worry for a chain of shops that already has a big system in place.

Syncing hurts most in a small business with a few units of expensive goods, where the same employee sells at the till and packs online orders.

Frequently asked questions

How quickly does the online store in NUNDINAE see the stock level?

The data is the same. The shop may keep some general information in a cache for a short time, but the actual stock level is checked when an order is placed.

What happens if two customers buy the last item at the same time?

The goods go to the one whose order set them aside. The other sees that the goods are no longer available.

Do I still need a stocktake?

Yes. Software doesn't know when a product broke or went missing on the shelf. A stocktake is done by CSV file or barcode scanner, and the correction stays in the history.

How can I compare different solutions?

I made a comparison of five common setups with integrations and costs.

Is your stock level drifting?

Describe which systems you have now and how often errors occur. Order NUNDINAE or ask for a demo. I'll look at your situation and tell you whether fixing the integration is enough.