With each system having its own list of inventory we need to make sure the SKU’s in the eCommerce site are the same as the SKU’s in Retail Express. The Supplier SKU is the most important one, but the Manufacturer SKU or "Grouping SKU" has a critical role too and is used alongside the Supplier SKU. 

This step is important not only in the setup but also to keep your products in sync with each system. The Supplier SKU is unique and is like the Barcode, the Manufacturer SKU is the grouping SKU.

It is certainly cleaner if there are no product in your eCommerce site while you setup REX.

Please check out our other support articles to gain a better understanding of how these SKUs are used throughout our integration.

Retail Express
E-Commerce Store
Unique Supplier SKU
For Simple Products
Same Manufacturer SKU and unique Supplier SKU.
Also would need a Size and/or Colour value set.
The Main Product will use Manufacturer SKU. The variants will go under the Main with their own supplier SKU.
For Variable Products

Simple Products

Supplier SKU: Test123

SKU on Ecommerce: Test123

Variable Products

Supplier SKUs: TestA | Manufacturer SKU: Test123

Supplier SKUs: TestB | Manufacturer SKU: Test123

Supplier SKUs: TestC | Manufacturer SKU: Test123

Will show products TestA,B,C under Test123 on your store.