# Pete Koomen

> Pete Koomen co-founded Optimizely during Y Combinator's Winter 2010 batch, building it from a pivoted idea in week two of YC into a $100M+ ARR experimentation platform before its 2020 acquisition. A former Google product manager who helped launch Google App Engine, Pete brought engineering rigor and scientific method obsession to the messy world of product decisions. He co-authored the field-defining book 'A/B Testing: The Most Powerful Way to Turn Clicks Into Customers,' and now serves as a Group Partner at Y Combinator, where he advises early-stage founders on enterprise sales, AI product design, and the art of building companies that actually figure out what works.

- **Role:** Visiting Group Partner at Y Combinator
- **Organizations:** Y Combinator, Optimizely, CarrotSticks
- **Nationality:** American
- **Education:** B.S. in Mathematics and Computer Science, Case Western Reserve University, M.S. in Computer Science, University of Illinois at Urbana-Champaign
- **Known for:** Co-founded Optimizely (YC W10) and grew it from zero to $100M+ in ARR before its acquisition in 2020, Helped launch Google App Engine, which reached 150,000+ developers, Co-authored 'A/B Testing: The Most Powerful Way to Turn Clicks Into Customers' (endorsed by Marissa Mayer)

## Career timeline

- **2004** — Graduated from Case Western Reserve University with dual B.S. in Mathematics and Computer Science
- **2004-2009** — Product Manager at Google, helped launch and grow Google App Engine to 150,000+ developers
- **2009** — Co-founded CarrotSticks with Dan Siroker, an online math learning platform for kids
- **2010** — Co-founded Optimizely during Y Combinator Winter 2010 batch; company pivoted from original concept in week two
- **2013** — Co-authored 'A/B Testing: The Most Powerful Way to Turn Clicks Into Customers' with Dan Siroker
- **2014** — Optimizely raised $57M in venture capital, expanded into Japan; serving ~8,000 enterprise customers including Disney and Starbucks
- **2015** — Received Young Alumni Achievement Award from the Siebel School of Computing and Data Science at the University of Illinois
- **2018** — Company reached ~400 employees; Jay Larson brought on as CEO while Pete continued as CTO
- **2020** — Optimizely acquired by Episerver (content management company); ARR had exceeded $100M
- **2022** — Joined Y Combinator as Visiting Group Partner for S22 batch
- **2023** — Joined Y Combinator full-time as Group Partner in October 2023
- **2025** — Published essay 'AI Horseless Carriages,' arguing that AI app design is lagging behind AI capabilities; role listed as Visiting Group Partner

## Achievements

- Co-founded Optimizely (YC W10) and grew it from zero to $100M+ in ARR before its acquisition in 2020
- Helped launch Google App Engine, which reached 150,000+ developers
- Co-authored 'A/B Testing: The Most Powerful Way to Turn Clicks Into Customers' (endorsed by Marissa Mayer)
- Received 2015 Young Alumni Achievement Award from the Siebel School of Computing and Data Science at UIUC
- Summited El Capitan in Yosemite (rock climbing)
- Angel investor in 10+ companies including Sublime Security, Cerbos, and Milk Video
- As YC Group Partner, advises a portfolio of companies with combined valuation exceeding $1.3B
- Pioneered enterprise experimentation culture that influenced how thousands of organizations make product decisions

## Latest updates

- **2025-04** — Published viral essay 'AI Horseless Carriages' arguing that most AI apps are poorly designed because they mimic outdated software patterns
- **2025-03** — Posted on LinkedIn about Y Combinator's 20th anniversary with reflections on the program's impact
- **2024-07** — Y Combinator shared Pete Koomen's Startup School video on enterprise sales, breaking down the enterprise sales funnel for technical founders
- **2023-10** — Joined Y Combinator as full-time Group Partner after serving as Visiting Group Partner

## Links

- Website: https://koomen.dev
- LinkedIn: http://www.linkedin.com/in/petekoomen
- Twitter/X: https://x.com/koomen
- GitHub: https://github.com/koomen
- Facebook: https://www.facebook.com/pete.koomen/

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Profile page: https://yespress.io/pete-koomen
Published by YesPress — https://yespress.io
Last updated: 2026-05-09