Short answer: for most categories, yes — Amazon requires a GTIN (UPC, EAN or ISBN), and it increasingly checks that the number is licensed to your brand in the GS1 database. Here is what that means in practice.
When you create a listing, Amazon asks for a product ID — usually a UPC or EAN. Amazon's policy states that GTINs are validated against the GS1 database, and that codes not matching the brand owner's registered prefix can be considered invalid. The consequence ranges from a blocked listing at creation to an existing listing being deactivated during a later sweep.
Sites selling "UPC codes" for a few cents are typically reselling numbers from prefixes registered decades ago to unrelated companies. The barcode artwork will scan fine — that was never the issue — but the ownership record points to someone else. Sellers report listings surviving for months and then being flagged. For a real brand, the GS1 licence is the cheap insurance.
If you sell handmade products, generic unbranded items, or parts that genuinely have no GTIN, Amazon offers a GTIN exemption you can apply for per category/brand inside Seller Central. Approved sellers list without a product ID. This is the legitimate "no barcode" route — not a purchased code of dubious origin.
Amazon itself only needs the digits typed into the listing. The printed barcode matters for FBA: if your product's packaging carries a scannable EAN/UPC, Amazon can track it by manufacturer barcode, or you can print Amazon's FNSKU labels instead. To produce print-ready artwork from your GS1 number, use our EAN-13 or UPC-A generator and export SVG.