When a Shopify store was connected to Amazon fulfillment, the connector app reported 66 unmatched and 10 duplicate items. It looked like a broken setup. It wasn’t. Most of the “errors” were simply products that never existed on Amazon. The only dangerous move would have been to switch on inventory sync for everything anyway.
The case
A merchant sells through his Shopify store and has some of the orders shipped from Amazon warehouses. Shopify and Amazon were to be connected via an app: orders from the store go to Amazon, inventory comes back. After the first sync, the dashboard read: 66 items unmatched, 10 duplicates.
What the numbers really meant
“Unmatched” doesn’t mean “broken”. The app compares every SKU in the store with the items on Amazon. If a product only exists in the store, say a gift set or a variant that never went into the Amazon warehouse, it finds no counterpart. That’s exactly as it should be.
Duplicates, on the other hand, are serious. If the same SKU exists twice, the app doesn’t know which stock belongs where. That has to be cleaned up before any automatic sync.
“Active” isn’t “in stock”. An item can be listed as active on Amazon and still have no stock in the warehouse.
Our approach
- Checked the list of unmatched items against the actual Amazon range. Result: most of them simply weren’t on Amazon.
- Checked and cleaned up the duplicates.
- Identified the items that really ship via Amazon, in this case just a handful of pack sizes.
- Switched on inventory sync only for those items, not for the whole catalog.
- Tested with test orders before real orders went through.
Your takeaways
- SKU mapping is the most important part of any warehouse integration. Not the app, not the settings.
- “Sync everything” is rarely the right first setting. Blindly syncing the whole catalog just automates your mess. In the worst case, the store sells stock that isn’t there.
- Clarify upfront which item comes from which warehouse. An item can come from your own warehouse, from a 3PL or from Amazon. Shopify handles this through locations, and each location needs its own rule.
- Read warnings, don’t just count them. 66 sounds like a lot. What matters is what’s behind it.
Want to connect Shopify to an external warehouse or a marketplace? We check SKUs and warehouse logic first, so the sync is right from day one.