Inventory & catalogue
How the Hub prevents double sales
3 min
The promise of the Hub is that the same copy is never sold twice. Not because everything syncs faster, but because there is exactly one place where a copy is counted and a fixed order in which a sale is processed: first booked off in the Hub, then withdrawn from the channels. This guide explains the mechanism, and is honest about the window that remains.
One copy, three layers
The catalogue describes what a release is. The copy in the Hub is the physical record: condition, price, place in the shop, quantity of one. The channels show that copy: your webshop, Discogs, Bol.com, eBay and the till. Only the middle layer has a quantity. Withdrawing a listing does not touch the stock; a sale does.
An order comes in online
An order arrives on Discogs, Bol.com, eBay or your webshop. Discogs is polled every minute; the other channels notify the Hub directly.
The Hub blocks the copy: quantity one becomes zero. This happens first, before anything else.
The Hub withdraws the listings on the other channels, typically within a few minutes.
The till sees the copy as sold from the moment of step 2.
Saturday morning, the same record
10.00: an order comes in on Discogs. 10.05: the Hub has blocked the copy and pulled it from the other channels. 10.30: a customer puts the same record on the counter. The till shows it as sold. You keep the record for the online buyer instead of cancelling the order afterwards.
A sale at the counter
The other direction has no window at all. The till sale is itself the booking: the moment the till reports it, the copy is at zero in the Hub, and the withdrawals on the online channels follow. Nobody can order a record online that has just been scanned at the counter, apart from the same few minutes it takes to withdraw the listing.
The window, honestly
Between the sale and the withdrawal on the other channels lies a window of at most a few minutes. Within that window a second buyer could, in theory, order the same copy on another channel. That is the real risk in the model, and it does not disappear by syncing faster; it shrinks. When it happens, the Hub keeps the first order and flags the second, so you cancel one order instead of discovering a week later that you shipped one record twice.
Why Discogs is polled
Discogs does not push orders; the Hub asks every minute. That is the longest leg in the chain and the reason the window exists at all. Your own webshop, Bol.com and eBay report immediately.
Returns and cancellations
A refund or a cancelled order does the reverse: the copy goes back to a quantity of one and is republished on every channel. The same applies to a refund in the till.
What this requires from you
Add and edit stock in the Hub, not in a channel. A record you add on Discogs itself is not counted.
Keep every product in the till, so a counter sale can be matched to a copy.
Use fair mode for crates that leave the shop, so those copies are offline while they are out of reach.
Two copies of the same pressing
Two copies are two records in the Hub, each with its own number and label. Selling one leaves the other for sale, with its own condition and price, on every channel.