Ok, glad you figured it out. Yeah, 9 for ePN. Those other affiliate networks aren't applicable anymore, since eBay consolidated worldwide affiliate tracking in-house via ePN. So, those other codes are irrelevant. Your AppID via eBay Dev Prog and CampID aren't linked. 2 different systems. And anyway, eBay Dev wouldn't know which of your ePN CampIDs to use anyway. So you need to specify. (Pro tip: after you get going, down the road you can build your own eBay affiliate links, and ignore the affiiliatized links returned by the API. Better control.) BTW, those other errant comments in this thread are spam; some1 trying to inject scripting into the forum.