Yeesshh auctions are managed under first price modality
When your bid wins, you pay exactly what you bid.
For your information, open RTB platforms offering traditional formats like banners, video or native, do operate under second-price auction (where if your bid wins, you pay $0.01 above the second highest bid in the auction). In the case of particular format nor reachable via Open RTB, like Pops or push, the standard is first price auction.