With Privy, you can use audience targeting to display campaigns only to visitors with certain product IDs in their cart (Shopify/Bigcommerce only):
To create a product upsell promotion, don't forget to add a rule excluding visitors who already have the product you're promoting in their cart:
Note: These targeting rules require product IDs found in your store admin. Do not enter a product SKU, product UPC, ISBN, GTIN, or MPN.
Finding Product and Variant IDs
Shopify: In your store admin, the product ID is the number at the end of the URL:
To get variant IDs, see https://help.shopify.com/en/themes/customization/products/variants/find-variant-id
Bigcommerce: In your store admin, the product ID is the number near the end of the URL: