An affiliate network is a marketplace that connects advertisers (merchants) with publishers (affiliates). The network handles tracking, attribution, fraud detection, and payments — taking a 20-30% cut of commission volume.
Well-known B2B SaaS networks include PartnerStack, Impact, and Tune. Consumer networks include CJ, Awin, ShareASale, and Rakuten. Choosing a network is mostly about which merchants they already represent in your vertical.