How does Unfilled Recovery work?

Last edited: 2025/07/29

1. The ad request is sent by your Ad Slot but ends up being unfilled by your demand.

2. The Unfilled Recovery Ad Unit is rendered. Unfilled Recovery operates based on Google Publisher Tag events and checks the ad server response.

   1. This step is triggered by the slotRenderEnded event.
   2. Size mapping is inherited from the original Ad Unit, ensuring there is no layout shift.

3. An auction is initiated using Yieldbird’s demand sources. These may include Google Ad Exchange, Open Bidding, Prebid (if the Prebid Stack is enabled), and Programmatic Deals.

4. A new ad is rendered, generating an impression and revenue.

   If the Unfilled Recovery Ad Unit is also not filled, the ad request is passed back to you (e.g. to serve house campaigns).