The variant object

AttributeDescription
idUnique identifier for the object.
product_idID of the product this variant belongs to.
material_idID of the material this variant belongs to.
skuA unique code for a product variant (also called SKU).
sales_priceDefault sales price (excluding tax), which is automatically assigned to the product or it's variant when creating sales orders. Can be manually changed on each order.
purchase_priceDefault purchase price (excluding tax) in the default currency of the supplier, which is automatically assigned to the material or its variant when creating purchase orders. Can be manually changed on each order.

If you are purchasing in a different unit of measure than your stock unit of measure, then this is the price per purchase UoM.
config_attributesAn array of variant configuration attribute objects (name and value). A variant can have configuration values to all options specified in the product object.
config_attributes.config_nameName of the variant option (e.g. color, size). Needs to match with the variant option from product.
config_attributes.config_valueValue of the variant option (e.g. blue). Needs to match with one of the variant option values from product.
typeEither "product" or "material", depending on the object the variant belongs to.
created_atThe timestamp when the variant was created.
updated_atThe timestamp when the variant was last updated.