FNSKU

The Fulfilment Network Stock Keeping Unit (FNSKU) is Amazon’s internal barcode used to track inventory within its fulfilment centers. It ensures that:

• Each item is associated with the correct seller, even if multiple sellers offer the same ASIN
• Amazon can track, store, and fulfill products accurately through FBA
• Sellers using FBA must apply an FNSKU barcode to each unit (unless using manufacturer barcodes under the stickerless commingled inventory program)

Key facts:

• FNSKU is a 12-character alphanumeric code, starting with “X”
• It appears on Amazon barcode labels generated in Seller Central
• Required for all FBA shipments unless the seller qualifies for manufacturer barcode exemption

💡 Example: If three sellers sell the same coffee mug via FBA, each will have their own unique FNSKU - even though the ASIN is identical.

In short:
FNSKU is Amazon’s tracking label for FBA products - ensuring each item is linked to the right seller and handled properly in the fulfilment network.