If several variants of one Shopify product share the same SKU, Shuttle can keep their stock levels the same. The syncing stays inside that product and the Etsy listing it is matched to, so other products that use the same SKU are not touched.
Turn on duplicate SKU syncing within one product
In Shuttle, open Stock Syncer and click Settings.
Find the Sync stock of duplicate SKUs section.
Tick Limit duplicate SKU syncing to the updated product.
Click Save.
To use the Sync stock of duplicate SKUs settings, you need the Growth plan or higher. They are also available during a Stock Syncer free trial.
Choose between the two duplicate SKU options
The Sync stock of duplicate SKUs section has two options. Only one of them can be on at a time, so ticking one unticks the other.
Limit duplicate SKU syncing to the updated product syncs variants that share a SKU within one product and the Etsy listing it is matched to.
Update all duplicate SKUs syncs a SKU across every product in both stores.
To learn more about syncing across all products, see Syncing Quantity Updates for Duplicate SKUs.
Which quantity does Shuttle use for variants that share a SKU?
Shuttle gives every variant with the same SKU the lowest quantity among them, so you never show more stock than you really have. It looks at all the variants in the product that share that SKU, takes the lowest quantity and gives it to each of them.
Example: other products with the same SKU stay as they are
When Limit duplicate SKU syncing to the updated product is on, Shuttle only updates the product that changed. Say you have two Shopify products, ABC and DEF, and both have variants with the SKU AAA123.
A customer buys the AAA123 variant of ABC. Shuttle updates every variant of ABC with the SKU AAA123, and DEF stays as it is.
Example: a T-shirt in two sizes and two colors
Variants of a T-shirt that share a SKU end up with the same quantity after a sale. This T-shirt has four variants. Both small shirts share one SKU, and both large shirts share another:
S + Blue: SKU TSmall, quantity 5
S + Red: SKU TSmall, quantity 5
L + Blue: SKU TLarge, quantity 8
L + Red: SKU TLarge, quantity 8
A customer buys the S + Red shirt in your Shopify store, so its quantity drops from 5 to 4. Shuttle then updates the T-shirt like this:
S + Blue: SKU TSmall, quantity 4
S + Red (sold): SKU TSmall, quantity 4
L + Blue: SKU TLarge, quantity 8
L + Red: SKU TLarge, quantity 8
S + Blue now matches S + Red because they share a SKU, and Shuttle also sends the quantity of 4 to the matching variations of your Etsy listing. The large shirts have a different SKU, so they do not change.
What happens when both duplicate SKU options are off?
When Limit duplicate SKU syncing to the updated product and Update all duplicate SKUs are both off, variants that share a SKU within one product are not updated when stock changes on Etsy. Shuttle pairs variations by SKU, so it cannot pair a SKU that is used more than once in a product. You will see a warning in your sync history when this happens.
To fix this, give each variation its own SKU.
For more details, see Duplicate SKUs Within a Product.