Quantity synchronization is probably the most important of the synchronization that we provide, and it's best you understand it well. We are going to make use of a listing on Shopify and eBay that are linked in SynCommerce to a particular base product.
First of all, this is what shows that your listings on both stores are linked in SynCommerce. From the products page, you will see both listings on both stores belonging to the same product.
Let's take a look at how you can provide and update your listing quantity. This can be done in two ways:
Updating Quantity on the Product
To update the quantity of the base product, go to the products page, and click on the name of the product you want to edit, or go to the far right of that product, click the "Action" button, and select "Edit". This will take you to that product's edit page, then scroll down to the variants section. Here, you can modify the quantities for the variants you have which will add up to the total quantity you have for that product.
If both the quantity for the Shopify and eBay listings are already the same at this point, then changing the quantity here will synchronize across both. For instance, if both had quantity 10, then changing the quantity to 15, will synchronize to make the Shopify listing quantity 10, and the eBay listing as well quantity 10. However, if say the quantity of the Shopify listing was 10, and the eBay listing was 5, then changing the product quantity from 10 to 15 will change the Shopify listing to 15, and the eBay listing to 10 (an increment of 5 across both stores). In that same scenario, reducing the product quantity from 10 to 4 will change the listing quantity on both stores to 4.
Updating Quantity on a Particular Listing
This is the only way you can have the quantity on one store different from the other stores. You can achieve this from the listings page, then clicking on the name of the listing or the edit icon at the far right to edit it. Note that from a particular listing's page;