Duplicate SKU checker for Shopify stores
Enter a store address and see in seconds which variants share a SKU, which have none and which SKUs contain hidden spaces. Marketplace sync apps match listings by SKU, so these are a common cause of overselling.
Anonymous: we keep only daily counts of checks. Store addresses and results are not saved, and there are no tracking cookies in the tool.
How it works
01Enter a store address
Any Shopify store with a public product feed: your own store or one you manage.
02We read the public feed
Up to 500 products and their variants from /products.json, with the same SKU rules the app uses.
03See the summary
Duplicate SKUs, variants without SKU and SKUs to clean, with up to three examples.
Questions about this tool
Why do duplicate SKUs cause overselling?
Marketplace sync apps usually match a listing to a Shopify variant by SKU. When two variants share a SKU, a sale or a stock update can be applied to the wrong one, so a listing keeps selling stock you no longer have.
Which SKU problems does the check find?
SKUs used by more than one variant (ignoring case and surrounding spaces), variants without a SKU and SKUs that contain invisible characters, leading or double spaces, or are longer than 40 characters (the Amazon seller SKU limit; eBay allows 50).
Why doesn’t it check stock levels?
The public product feed shows whether a variant is sold out, but not inventory tracking, the “Continue selling when out of stock” setting, locations or channels. The app reads those from Shopify.
Can I check a store that isn’t mine?
Yes, the check only reads data the store publishes for everyone. It respects robots.txt, reads at most 500 products and keeps nothing after showing the result.