Merchlint – Duplicate SKU and GTIN Finder for WooCommerce

Install this plugin, open Tools → Duplicate SKU and GTIN Finder and press Scan now. Every product that shares its SKU with another one is listed with the SKU that was read and an Edit link, and Download CSV gives you the same list as a file. It compares published products and their variations; translations of one product are not counted as duplicates. WooCommerce itself refuses a repeated SKU when you save a product, but it has no screen that lists the pairs already in your catalogue. Those got in another way - for example through a tool that writes to the database directly.

WooCommerce shows this message when you save a product with an SKU that another product or variation already has. A draft or a private product holds its SKU too; only a product in the Trash does not. In the classic product editor your other changes are saved, and the SKU keeps its previous value. To find the product that holds it, type the SKU into the search box under Products → All Products. That search covers drafts, private products and the SKUs of variations, and for a variation it shows the product the variation belongs to. This plugin lists published products and their variations only, so a draft holding the SKU will not be on its list. The identifier field has its own version of the message, "Invalid or duplicated GTIN, UPC, EAN or ISBN." (WooCommerce 9.2 and later), and it works the same way. Since WooCommerce 11.2 the product CSV importer, with Update existing products ticked, also finds products by their GTIN. A row whose GTIN two products share fails with this message, and neither product changes; the importer does not say which product holds the other copy. The list from this plugin shows which published products share it.

Since WooCommerce 9.2 every product has a field for a GTIN, UPC, EAN or ISBN, but nothing in the admin lists the products where it is empty. This plugin does: each one with an Edit link, and a variable product once, with the number of its variations that have no code.

This plugin does not check the number itself. It finds products with no GTIN and GTINs used by more than one product. To check the check digit, the length and the format of a whole list of codes, use the free GTIN validator on our website: paste a column of codes or pick a product export file (CSV, TXT or XLSX). It runs in your browser, and the file is not sent anywhere. A well-formed number is not yet proof that it belongs to the product. Only the GS1 registry shows whether the manufacturer registered it.

No. It reads the catalogue and writes nothing back. It keeps a few things of its own: the last result, so that reloading the page does not require another scan, and a note in your user profile once you answer the review request or hide the note about Merchlint under the results, so that neither comes back. Deleting the plugin removes all of them.

No. Translations of one product share an SKU on purpose, and the check treats one translation group as one product. Polylang and WPML are both read.

No. If not one product in the catalogue has the field filled, the check stays quiet and tells you why, in one sentence.

Only if you connect one yourself. On WordPress 6.9 or later the plugin registers two read-only abilities through the WordPress Abilities API: the summary of the last scan and the list of its findings. An AI assistant you connect to your store, for example through an MCP plugin, can call them as a logged-in user with the manage_woocommerce permission, and gets the same results as the Tools screen. The plugin itself sends nothing anywhere and changes nothing in your shop.