GTIN, Global Trade Item Number, is the umbrella for the barcode numbers commerce runs on: UPC (12 digits, North American retail), EAN (13 digits, most of the world), and longer variants for cases and books (ISBN is a GTIN in disguise). Online sellers meet GTINs as a marketplace field: sometimes required, sometimes exempt, always worth getting right, because platforms use them to decide WHICH product your listing is.
What GTINs do on marketplaces
Marketplaces use GTINs for catalog matching: a GTIN on your listing tells the platform your offer belongs to an existing product page (Amazon matching to an ASIN) or anchors a new one. Get it right and your offer joins the right page with its reviews and search history; get it wrong and you create duplicates, mismatches, or rejections, the identity problem at the global level, where your internal SKU is the identity YOU control and the GTIN is the identity the WORLD shares.
Requirements differ by platform and category: Amazon requires GTINs for most branded categories (with brand-registry and exemption paths), eBay requests them for cataloged products and rewards them in search, Etsy does not require them (handmade is the point), and Google Shopping feeds lean on them for product matching.
Sourcing codes legitimately
GS1 is the source. GTINs are issued through GS1 licenses: a company prefix (your codes forever, annual fee, scales cheaply per code) or single GTINs for tiny catalogs. Codes you license are registered to YOUR company name, which matters because platforms increasingly validate GTIN ownership against the GS1 registry.
The recycled-code market is the trap. Cheap “UPCs” from resellers are usually recycled prefixes registered to other companies decades ago. They scan fine and fail modern validation: listings rejected, offers matched to the wrong catalog products, and brand-name mismatches you discover at the worst time. The savings are two digits; the cleanup is duplicate-and-mismatch archaeology.
Reseller of branded goods? You do not create GTINs, you USE the manufacturer’s, listing against the existing catalog product. Creating a new code for someone else’s product is how mismatches are born.
Exemptions: when you do not need one
Handmade, custom, one-of-a-kind, and many private-label cases have exemption paths: Amazon grants GTIN exemptions by brand/category application (standard for handmade and generic goods), Etsy never asks, and eBay accepts “does not apply” where the product genuinely has no code. The rule of thumb: if the product exists only because you made it, an exemption is usually cleaner than buying codes it never carried, Etsy-style catalogs run entirely this way.
Operational placement
- Store the GTIN as a product attribute in your source of truth, per variant (children carry codes, not parents), alongside, never instead of, your SKU.
- Feed it to channels through the catalog data, one field, filled once, data-quality pass, not per-listing typing.
- Barcodes on physical units (receiving and picking) can encode the GTIN or your SKU; small operations usually barcode the SKU and keep GTINs as data.
Common questions
UPC or EAN - which do I buy?
They are the same system at different lengths; GS1 licenses issue what your region uses, and platforms accept both. A 12-digit UPC with a leading zero IS its 13-digit EAN.
Do I need a new GTIN per variant?
Yes, each sellable variant (color-size) is its own trade item with its own code, mirroring the child-SKU rule.
Can I sell without GTINs entirely?
On Etsy and for exempt categories elsewhere, yes. The moment you enter GTIN-required marketplace categories with branded goods, the field stops being optional.
Are GTINs the same as ASINs?
No, ASIN is Amazon’s internal identifier, minted by Amazon. GTINs are the cross-platform codes that help Amazon decide which ASIN your offer joins.
Identity at every level
SKUs you control, GTINs the world shares, matched and synced across every channel, from $49/month with unlimited orders. See pricing.