Affiliate tracking is technology used to track the traffic, referrals, and/or sales that come through a specific partner. The purpose of affiliate tracking is so that a company knows which affiliates drive favorable business outcomes (in other words, attribution), and can reward these individuals accordingly. UTM links are the most common mechanism for affiliate tracking.

Affiliate tracking can also be achieved using promo codes. For example, if an influencer can offer his or her audience 10% off a 1-year software subscription with the promo code PERCY10, this allows the company to track precisely how many sales Percy drives. This then enables the company to determine which partnerships are most lucrative and invest in building these relationships and enabling them to do their best work.