The phone call that explains the problem goes like this. A customer calls to ask if you have the blue one in a large. You walk to the back, check the shelf, check the floor. You think you might have one but you are not sure because someone bought something online this morning and you haven't looked at those orders yet. You tell the customer you'll call them back. By the time you do, they've found it somewhere else.
That conversation happens because most independent retailers are running two separate inventory systems with no connection between them. The physical store has a POS — Square, Lightspeed, Shopify POS — that knows what is in the building. The website has its own product catalog with its own stock numbers. When something sells in the store, the website doesn't know. When something sells online, the store doesn't know. Both systems are operating on information that is wrong the moment a sale happens on the other side.
The most expensive version of this problem is the oversell. A customer buys the last size medium of a popular item in-store on Saturday afternoon. The website still shows it as available. A different customer orders it online Sunday morning. Now you have one item and two people expecting it. Someone gets an apology email. That customer's trust doesn't fully recover, and they probably don't come back.
Only 36% of retailers report full inventory visibility across their channels, according to Linnworks research from 2025. The other 64% are managing a gap they've normalized because it has always been there.
The fix depends on what you are running. If your in-store and online are both on Shopify, the inventory is unified natively — one system, one record, updated in real time regardless of where the sale happens. If you are on Lightspeed with a separate Shopify store, a sync tool like Octopus from 24SevenCommerce connects both with continuous two-way inventory updates. It prevents the Saturday afternoon oversell because both systems see the same number.
The side effect that often surprises retailers who fix this: it enables buy online, pick up in store. BOPIS is one of the most requested fulfillment options from retail customers. It requires real-time inventory visibility to work reliably. Retailers with split inventory cannot offer it without risking the embarrassing "sorry, that item is not actually here" pickup experience.
The inventory is in your store. The sales are happening on both sides of your business. The question is whether both sides of your business know what the inventory actually is.
Michelle Onizuka is co-founder and Systems Architect at Onizuka Studio. She builds automation and AI systems for small businesses — including independent retail operations across Tampa Bay and beyond.