Brian O'Kelley.

Brian O’Kelley is the CEO and co-founder of Scope3, building infrastructure for agentic advertising.

Brian was the co-founder and CEO of AppNexus through its $1.6B sale to AT&T in 2018. He co-founded Waybridge, a supply chain technology company, and served as CTO of Right Media through its successful acquisition by Yahoo for $850M in 2007. He was on the board of LiveRamp leading up to its sale to Publicis for $2.2B in 2026.

Brian architected the Ad Context Protocol (AdCP) to establish the technical foundations for agents to execute advertising transactions. He invented many of the key technologies behind the $100B+ programmatic advertising industry including the ad exchange, the DSP, the SSP, and header bidding. He was the original author of the open source Prebid Server project, and holds 17 patents.

Brian has been named to Crain’s 40 Under 40, Adweek 50 and Silicon Alley 100 lists, and was recognized as an E&Y Entrepreneur of the Year in the New York region. Brian was an early supporter of Girls Who Code, actively supports Moms First, and supports One Acre Fund’s 1 Billion Trees campaign to invest in Africa's smallholder farmers to build resilient communities.

Brian has a B.S.E. in Computer Science from Princeton University. He lives in Brooklyn with his wife, two daughters, and Donutella the cat.

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