UPC And EAN Barcodes Requirements For Zappos and 6pm.com Vendors UPC And EAN Barcodes must be GS1 Certified when conducting business with Zappos and 6pm.com. Vendors should place a human-readable and scannable UPC label (12 digits) or EAN label (13 digits) on every individual product packaging sent to the FC. Only one UPC or one EAN should be Read More →