Dynamic floors

Dynamic floors are price floors that change automatically with the conditions of each auction, such as ad size, device, country, time or recent demand, instead of being set once by hand.

A floor is the lowest price a bid must reach to compete. Static floors are blunt: one price for every impression is too high for some and too low for others. Prebid's Price Floors Module lets a publisher, or a floor provider it hires, define rules across dimensions such as media type, size and domain. In the dynamic setup, the module fetches floor data from the provider's endpoint and may delay the auction by up to auctionDelay milliseconds to receive it (Prebid.org, accessed 9 November 2026).

Bid adapters read the floor for each slot with getFloor() and pass it to their bidders. The module then rejects bids below the floor. It also sends floor and bid data to analytics adapters, so the provider can retrain its model. The skipRate setting, from 0 to 100, skips floors on a random share of auctions to measure what floors change. Prebid Server supports a similar feature using the same rule schema.

Example: A floor provider returns $1.20 for 300x250 mobile slots in the US and $0.40 for the same slot elsewhere. With skipRate: 5, about 5% of auctions run with no floor. The provider compares revenue in the two groups and adjusts the next rule file.

Related terms: floor price, private marketplace deal floor, yield management, bid shading, first-price auction, Prebid.js.

Authoritative source: Prebid.org, "Module: Price Floors" (accessed 9 November 2026).

Read the full guide: Floor price strategy in first-price auctions.