Hi,

Welcome to the Seller Forums!

FNSKU stands for Fulfillment Network Stock Keeping Unit. FNSKUs are unique identifiers for both the product and the FBA product listing. These automatically generate when you create FBA listings, so they are used only on Amazon unless you decide to use them outside of Amazon.

If you are using third party software to manage your inventory I would recommend working with them to determine what identifiers they use to manage your products.

I hope this helps.

Jessica