What is in-app bidding?
In-app bidding is the mobile-app version of header bidding: an app's ad mediation platform runs a simultaneous auction among many ad networks and exchanges for each impression, instead of calling them one by one in a fixed waterfall. It usually raises app developers' revenue and reduces manual setup, and is now standard in mobile gaming.
Historically, app ad mediation platforms used a waterfall ranked by historical eCPM. In-app bidding (also called unified bidding) lets every network bid in real time. Major platforms include AppLovin MAX, Google AdMob, Unity LevelPlay and others.
Bidding also concentrates power in whoever runs the mediation auction, a concern that echoes the web's antitrust debates. For advertisers, in-app inventory needs app-ads.txt checks and fraud filters for hidden ads and background impressions.