Glossary
What is Prebid.js?
Also called: Prebid, pbjs
Prebid.js is free, open-source JavaScript that runs header bidding auctions in the reader's browser and passes the best bids to the ad server.
हिंदी में पढ़ेंPrebid.js is the browser part of Prebid, the open-source header bidding project. It is free to use, Prebid says it supports more than 300 demand partners, and your page talks to it through the pbjs object.
A typical auction runs in five steps. The page tells Google Ad Manager to wait. Prebid reads your ad units, each with its sizes and bidders. It calls all the bidders at once and starts a timer. It rounds the best bid into a price bucket and sets key-values such as hb_pb, hb_bidder and hb_adid. Then the ad server runs, and if the Prebid line item wins, the Prebid Universal Creative renders the winning ad.
Your site loads a build containing only the bid adapters and modules you chose. Prebid supports only its most recent major version, 11 since March 2026, and suggests upgrading at least every six months.
Example
Prebid asks three bidders with a 1,000 ms timeout. A bids $2.10, B bids $1.85 and C answers late, so it is left out. Prebid sends hb_pb=2.10 to Ad Manager, where the bid competes with the other demand.
Why it matters to publishers
Prebid.js decides which bids reach your ad server and affects how fast pages load, so its version, adapters and settings directly affect revenue.