Why does my Shopify keep overselling?
You sold three of something you only had two of, again. It is rarely bad luck. It is almost always because no single system owns the stock number, so Shopify, your other channels and your warehouse are each working from a slightly different picture, and the gap shows up as an oversell on your busiest day.
The mechanics of an oversell
Every channel has its own copy of the number
Shopify, your marketplaces, your POS and your 3PL each hold a stock figure. None of them updates the others instantly, so for a window every day they all disagree.
Sync apps poll, they do not own
Most inventory apps check in on a schedule and push an update after the fact. Between checks, two channels can both sell the last unit before either one hears about it.
Bundles and multi-location stock hide the real count
A kit made of three components, or stock split across a warehouse and a shop floor, is exactly where a simple "set the Shopify quantity" sync falls over.
It always happens on the day that matters
Oversells cluster around your busiest hours, because that is when stock is moving fastest and the gap between reality and what each channel believes is widest.
One system owns the number. Shopify can't oversell it.
Stock stops being something Shopify guesses at and becomes something it reads live from a system that actually owns it. The moment an order lands anywhere, the number updates everywhere else before the next sale can happen. There is nothing left to reconcile, because there was never a second copy to disagree with.
Odoo becomes the source of truth. Shopify just sells.
We build the stock system on Odoo, the open-source commerce ERP, and connect your Shopify store to it with our own connector. Odoo holds the real, single stock number; every location, bundle and channel deducts from it directly, so Shopify is never working from a stale copy. If the sync ever breaks, we fix it ourselves, not a third-party app team you have to wait on.
This is the same architecture behind Gandys, a UK lifestyle brand where we unified three Shopify stores, marketplace orders and a 3PL onto one owned stock number, and behind the connectors we built for selling on bol.com and Amazon, where overselling carries a real financial penalty from the marketplace itself.
See how the pieces fit
Shopify-Odoo Connector
Our own connector, syncing orders, inventory, products and refunds both ways.
Multichannel inventory & stock sync
Selling on more than Shopify? See how one number covers every channel.
Odoo vs Shopify as a backend
When your storefront can no longer be your back office.
Selling on Shopify and Amazon together? See how to keep the two in sync →
Ready to fix your ops?
Book a free discovery call. We'll look at your current setup and tell you honestly whether Odoo is the right move and what it would involve.