# Brian O'Kelley

> Brian O’Kelley is an American technology entrepreneur and engineer who co-founded AppNexus and Scope3. He led AppNexus through its 2018 acquisition by AT&T, co-founded commodities supply-chain company Waybridge, and returned to advertising with Scope3’s emissions-measurement business. Scope3 rebranded as Apostra in September 2026, focusing on agentic advertising; O’Kelley is its co-founder and CEO and the lead architect of the open Ad Context Protocol.

- **Role:** Co-founder and CEO at Apostra (formerly Scope3)
- **Organizations:** Apostra, Scope3, AppNexus, Waybridge, Right Media, Tech:NYC, LiveRamp (appointed to board in 2023), AgenticAdvertising.org
- **Nationality:** American
- **Education:** B.S.E. in Computer Science, Princeton University, Supply Chain Comprehensive Exam verified certificate; not a degree, MITx / edX
- **Known for:** Helped develop early advertising-exchange technology as CTO of Right Media., Co-founded and led AppNexus from 2007 through its acquisition by AT&T in 2018., Co-founded Scope3 to measure and reduce advertising supply-chain emissions.

## Career timeline

- **1999** — Graduated from Princeton University with a B.S.E. in computer science.
- **2003–2007** — Served as CTO of Right Media, which Yahoo acquired in 2007.
- **2005** — Right Media launched four networks on Yield Manager on April 1, according to his published recollection.
- **2007** — Co-founded AppNexus with Mike Nolet.
- **2012** — Received EY Entrepreneur of the Year recognition in the New York region with Mike Nolet.
- **2018** — AT&T acquired AppNexus; the price was widely reported at approximately $1.6 billion.
- **2019–2021** — Co-founded Waybridge and served as CEO until December 2021.
- **2021–2022** — Co-founded Scope3 in December 2021; the company launched publicly in January 2022.
- **2023** — Joined LiveRamp’s board in February; Scope3 announced a $20 million Series B led by GV in October.
- **2025** — Scope3 introduced its Agentic Media Platform; O’Kelley published four memoir chapters about early programmatic advertising.
- **2026** — Scope3 rebranded as Apostra in September, emphasizing agent-to-agent advertising.

## Achievements

- Helped develop early advertising-exchange technology as CTO of Right Media.
- Co-founded and led AppNexus from 2007 through its acquisition by AT&T in 2018.
- Co-founded Scope3 to measure and reduce advertising supply-chain emissions.
- Lead architect of the open Ad Context Protocol.
- Named an EY Entrepreneur of the Year in the New York region in 2012.
- Recognized in Crain’s 40 Under 40 and Adweek 50.

## Latest updates

- **2026-10** — Co-authored The Universal Buying Platform with Anne Coghlan, discussing cross-media buying and workflow orchestration.
- **2026-10** — Spoke at Advertising Week New York as co-founder and CEO of Apostra.
- **2026-09** — Scope3 became Apostra; Coghlan announced the launch on September 23 and O’Kelley explained the ad-gateway architecture on September 24.
- **2026-04** — Published Doing It Backwards, defending public development of AdCP and discussing governance and architectural risk.

## Links

- Website: https://bokonads.com/
- LinkedIn: https://www.linkedin.com/in/brianokelley
- Twitter/X: https://x.com/bokelley
- GitHub: https://github.com/bokelley

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Profile page: https://yespress.io/brian-okelley
Published by YesPress — https://yespress.io
Last updated: 2026-10-26