An advertising system receives, from a merchant system, marketing information, bidding preferences for auctions for advertising spaces, and a merchant system reservation calendar comprising an availability for the merchant system. The advertising system receives a notice of an auction for an advertising space from an advertising platform. The advertising system determines a first bid for the auction based on the availability of the merchant system, the marketing information, and the merchant system's bidding preferences and transmits the first bid to the advertising platform. The advertising system receives a notice of an incomplete auction from the advertising platform. The advertising system receives, from the merchant system, an updated merchant system reservation calendar comprising an updated availability and determines a second bid for the advertising space auction. The advertising system transmits the second bid to the advertising platform. The advertising system receives a notice of a completed auction from the advertising platform.