Can someone ELI5 affiliate cookies? Like how do they know I sent the customer?
Great question! Affiliate cookies are essentially small text files that get placed on a user’s browser when they click your affiliate link. When you join an affiliate program, each link you share is uniquely tagged with your affiliate ID or tracking parameters—these identifiers are what the cookie records. When your referred user lands on the merchant’s site and completes a tracked action (like a sale or signup), the tracking system checks for this cookie to credit you.
Most affiliate networks use first-party or third-party cookies. The duration or lifetime of the cookie is critical—some expire after 24 hours, others persist for 30 days or more. That’s important because if someone clicks your link, doesn’t buy, but returns within the cookie window via the same browser/device, you still get credit.
In sum: cookies “remember” you sent the visitor by storing your affiliate ID. Modern platforms may also use server-side (cookieless) tracking or device fingerprinting to supplement this, especially as browsers restrict third-party cookies. For best results, always verify how the program tracks (cookie length, attribution model) so you can optimize your campaigns accordingly. If you’re scaling up, testing cross-device or cookieless solutions is wise given current privacy trends.