Third-party cookies are going away
Affiliate programs have long relied on third-party cookies to remember which link a shopper clicked. Browsers now block or limit those cookies, which makes cookie-based affiliate tracking increasingly unreliable, especially across the days between a click and a purchase.
Use Shopify's server-side webhooks
Shopify emits signed paid-order webhooks from its own servers when a sale completes. Those events are authoritative and do not depend on anything in the shopper's browser. Attribloom credits a validated affiliate discount code or the referral preserved in Shopify note attributes, so attribution survives third-party cookie loss.
From there, the commission is applied to the post-discount merchandise subtotal in the store's currency, excluding tax and shipping, and reversed if the order is later refunded.