Prebid.js

De facto open-source standard for header bidding, used by hundreds of thousands of publishers globally

Prebid.js is the most widely adopted open-source header bidding solution in the digital advertising ecosystem, maintained by Prebid.org — a non-profit organization governed by industry stakeholders including major publishers, SSPs, and ad tech companies. Originally created by AppNexus in 2015 and later donated to the open-source community, Prebid.js allows publishers to run simultaneous auctions among multiple demand partners before calling their ad server, dramatically increasing competition and yield compared to traditional waterfall setups. The Prebid ecosystem has expanded well beyond its JavaScript origins to include Prebid Server (a server-side header bidding solution), Prebid Mobile (for iOS and Android apps), and Prebid Video, among others. With hundreds of demand partner adapters and a massive contributor community, Prebid.js is estimated to be deployed on hundreds of thousands of websites globally, making it the de facto standard for header bidding implementation. Its governance by a neutral non-profit body ensures no single commercial entity controls its direction. In the AdTech ecosystem, Prebid.org occupies a uniquely influential position as an open, vendor-neutral alternative to proprietary header bidding wrappers. It competes indirectly with managed header bidding solutions from companies like Google (Open Bidding), Amazon (TAM), and Index Exchange, but its open-source nature and broad industry support make it complementary to many commercial offerings. The project is critical infrastructure for the modern programmatic advertising supply chain.