Proper.io is an ad exchange. That means they work as a middleman between advertisers who buy ad space and publishers who sell ad space. Proper.io has been authorized to sell the ad space on 431 publisher domains. You can view these domains below.
0.05% of the publishers we track have authorized proper.io.
Download the complete list of publishers for this ad exchange and use the data in your systems. You can access both the list of publishers and the list of ads.txt records (including SellerID) authorizing this exchange.