What is a SKU?

A SKU (Stock Keeping Unit) is a code a seller creates to identify each product variant in inventory — different colors, sizes, or models each need their own SKU. It's what links warehouse stock, sales records, and accounting reports together. The common confusion is treating a SKU as the same thing as a barcode. A barcode is a standardized code such as EAN-13 or UPC, assigned by the manufacturer or a body like GS1, scannable anywhere in the world, and fixed regardless of which shop sells the item. A SKU, by contrast, is entirely seller-defined and can be structured however your inventory system needs. A workable SKU format usually follows [category]-[color]-[size], for example TSH-BK-L for a black T-shirt in size L, or SH-WHT-42 for white shoes in size 42. Two rules matter most: never reuse a SKU across different products, and keep the same format across the whole shop from day one, before stock volume makes it painful to fix. Sellers on Shopee, Lazada, or TikTok Shop each get a separate Seller SKU field, distinct from the platform's own product ID. If the SKU doesn't match across channels, pulling sales reports for stock or revenue reconciliation makes it hard to match the same product between platforms — you end up checking line by line. The workaround is using one shared SKU set across every channel from the start. MooMooNext's marketplace reconciliation feature (see the marketplace reconciliation feature page) uses SKU to group records when importing sales reports from multiple platforms, so owners or accountants can review stock and per-product sales more easily.