Shopify tracks stock for each variant, but an Etsy listing can either track stock for each variation or keep one quantity for the whole listing. For listings that keep one quantity, the Use lowest variant quantity for product-level Etsy listings setting lets Shuttle use your lowest Shopify variant quantity, which helps you avoid overselling.

Say you sell a shirt with these quantities in Shopify:

With Use lowest variant quantity for product-level Etsy listings turned on, the Etsy listing's quantity becomes 3 when Shuttle updates the product, because 3 is the lowest variant quantity.

The Use lowest variant quantity for product-level Etsy listings setting applies when Shuttle updates a product that is already listed on Etsy and keeps one quantity for the whole listing. Variants that don't track stock in Shopify are left out when Shuttle finds the lowest quantity.

For a listing with one quantity for the whole listing, stock syncing uses the lowest variant quantity whether the Use lowest variant quantity for product-level Etsy listings setting is on or off. So the setting only affects product updates.

The Use lowest variant quantity for product-level Etsy listings setting does not apply to new transfers. You can still give new Etsy listings one quantity for the whole listing, which has its own article.

See Simplify Inventory Management by Setting Product-Level Stock Quantities on Etsy.

For products with more than one variant, a filled-in Default stock quantity takes the place of the lowest variant quantity. If you filled in Default stock quantity in the same Quantity section, Shuttle uses that number instead.

Leave Default stock quantity empty if you want Shuttle to use the lowest variant quantity.