People

President & CEO

Garry Tan is president and CEO of Y Combinator. He was a partner at Y Combinator from 2011 to 2015, where he built key parts of the YC experience for founders including Bookface and the Demo Day website. Garry is the co-founder of Initialized Capital and Posterous (YC S08), a blog platform acquired by Twitter, and prior to that, he was an early designer and engineering manager at Palantir (NYSE:PLTR), where he designed the company logo. Garry holds a BS in Computer Systems Engineering from Stanford.

Group Partners

Gustaf Alströmer

Group Partner

Gustaf Alströmer is a Group Partner at YC. He spent 4.5 years at Airbnb where he worked as a Product Lead on the Growth team, a team he helped start in 2012. Prior to Airbnb, Gustaf was Head of Growth at Voxer, and before that, he was CEO & co-founder of Heysan, which was part of the YC W07 batch.

Tom Blomfield

Group Partner

Tom Blomfield is a Group Partner at YC. He was co-founder of Monzo, one of the first app-based challenger banks in the UK. Monzo raised more than £500m, counts 10% of the UK population as customers, and was the \#1 recommended brand in the UK for two years running. Previously, he founded GoCardless (YC S11), an online payments processor for the Direct Debit system. In 2019, he was awarded an OBE for increasing competition in the banking sector.

Paul Buchheit

Group Partner

Paul Buchheit is a Group Partner at YC and the creator of GMail. While at Google he also built the prototype for AdSense and came up with Google’s famous slogan “Don’t be evil.” In 2007 he was one of the founders of Friendfeed, which in 2009 became Facebook’s largest acquisition to date. He has a BS and MS in Computer Science from Case Western Reserve University.

Dalton Caldwell

Managing Director, Investments and Group Partner

Dalton Caldwell is Managing Director, Investments and Group Partner at YC. He was the cofounder and CEO of imeem (acquired by MySpace in 2009), and the cofounder and CEO of App.net. He has a BS in Symbolic Systems and a BA in Psychology from Stanford University.

Nicolas Dessaigne

Group Partner

Nicolas Dessaigne is a Group Partner at YC. He was the co-founder of Algolia (YC W14), a growth stage Search API used by millions of developers. He led the company as CEO up to 350 people before hiring a successor in 2020. He is still very involved in the success of Algolia as Board Director. He has a PhD in Computer Science from the University of Nantes.

Aaron Epstein

Group Partner

Aaron Epstein is a Group Partner at YC. He was co-founder of Creative Market (YC W10), a marketplace for graphic design assets, which he sold to Autodesk in 2014 and spun out as an independent startup again in 2017. Aaron founded the company to make beautiful design simple and accessible to everyone, and has since helped generate more than $100M in sales for independent creators around the world. He has a BS in Business from the University of Maryland.

Brad Flora

Group Partner

Brad Flora is a Group Partner at YC. He was co-founder and CEO of Perfect Audience, an ad network funded by Y Combinator in 2011, acquired by Marin Software in 2014 and used by companies like Eventbrite, Atlassian, and New Relic to market to more than a billion people. He is an active angel investor, occasional contributor for Slate.com and lives in San Francisco with his wife and three children. He has a BA from Princeton University in English and an MS in Journalism from Northwestern.

Jared Friedman

Managing Director, Software and Group Partner

Jared Friedman is Managing Director, Software and Group Partner at YC. He was cofounder of Scribd, which was funded by Y Combinator in 2006 and grew to be one of the top 100 sites on the web. Jared previously worked at a pioneering AI company and studied computer science at Harvard.

Diana Hu

Group Partner

Diana Hu is a Group Partner at YC. She was co-founder and CTO of Escher Reality (YC S17), an Augmented Reality Backend company that was acquired by Niantic (makers of Pokémon Go). At Niantic, she was the head of the AR platform. Previously, she led data science at OnCue TV that was sold to Verizon. Originally from Chile, Diana graduated from Carnegie Mellon University with a BS and MS in Electrical and Computer Engineering with a focus in computer vision and machine learning.

Surbhi Sarna

Group Partner

Surbhi Sarna is a Group Partner at YC. She was the founder and former CEO of nVision Medical, which developed a first-in-kind microcatheter for the detection of ovarian cancer. After raising $17M in venture funding, completing three clinical trials, and obtaining two first-in-class FDA approvals, nVision was acquired by Boston Scientific (NYSE: BSX) for $275M, more than 15X money-in. Surbhi stayed at Boston Scientific for two years, running the 150+ person commercial organization in preparation for launch. She sits on both private and public company boards.

Michael Seibel

Managing Director, Batch and Group Partner

Michael Seibel is Managing Director, Batch and Group Partner at YC. He was the cofounder and CEO of Justin.tv and Socialcam. Socialcam sold to Autodesk in 2012 and under the leadership of Emmett Shear, Justin.tv became Twitch.tv and sold to Amazon in 2014. Before getting into startups, he spent a year as the finance director for a US Senate campaign and in 2005, Michael graduated from Yale University with a BA in political science.

Harj Taggar

Managing Director and Group Partner

Harj Taggar is a Managing Director and Group Partner at YC. He was previously founder and CEO of Triplebyte (YC S15) and Auctomatic (YC W07), which was acquired by Live Current Media in 2008. He first joined YC as a partner in 2010, leaving in 2014 to start Triplebyte and rejoining in 2020. He graduated in 2006 from Oxford, where he studied Jurisprudence.

Visiting Group Partners

Rich Aberman
Rich Aberman was co-founder of WePay (YC S09), a payments API for B2B SaaS and point-of-sale platforms. As Chief Product and Strategy Officer, he helped raise $75M in venture capital, grow the company to 300 employees, and achieve profitability before being acquired by JPMorgan Chase in 2018. He holds a degree in economics, political science, and philosophy from Boston College.
Wayne Crosby
Wayne Crosby was the co-founder of Zenter (W07), the collaborative presentation product that was acquired by Google and turned into Google Slides. Wayne also founded Humu, a product that uses behavioral science and machine learning to help teams at large enterprises achieve greater happiness and better performance, and OrgOrg, which builds tools to help small businesses and organizations run more efficiently.
Umur Cubukcu
Umur Cubukcu was the co-founder and CEO of Citus Data (S11), the creators of the distributed PostgreSQL database Citus. Citus Data was acquired in 2019 by Microsoft, where he spent nearly four years leading the PostgreSQL product team at Azure. He received his MS from Stanford University.
Pete Koomen
Pete Koomen co-founded Optimizely (W10) which helps companies run experiments on their websites and apps. He helped Optimizely grow from inception, to $100M+ in ARR to, ultimately, its acquisition in 2020. Pete holds a Master’s degree in Computer Science from the University of Illinois at Urbana Champaign.
David Lieb
David Lieb was previously the co-founder and CEO of Bump (S09), which was acquired by Google in 2013 and evolved into what is now Google Photos. Before Bump, Dave was a researcher in the Stanford AI Lab and a software engineer at Texas Instruments. He holds EE/CS degrees from Princeton and Stanford and finished ½ an MBA at Chicago Booth before dropping out to start Bump.
Emmett Shear
Emmett Shear was co-founder and CEO of Twitch, the massively popular live streaming service that began its life as Justin.tv (W07). Twitch was acquired by Amazon in 2014, with Emmett staying on as Twitch’s CEO until he stepped away from the role in 2023. He graduated from Yale University in 2005 with a degree in computer science.

Founders

Trevor Blackwell
Founder, Retired
Trevor Blackwell is a roboticist who in 2007 built the first dynamically balancing [biped robot](http://www.youtube.com/watch?feature=player_embedded&v=_CQ5AKaEi3U). He has published papers on congestion control in high speed wide area networks, signalling protocol architecture, and file system performance. He has a BEng from Carleton, and a PhD in Computer Science from Harvard.
Paul Graham
Founder, Retired
Paul Graham is the author of [On Lisp](http://www.amazon.com/exec/obidos/tg/detail/-/0130305529/) (1993), [ANSI Common Lisp](http://www.amazon.com/exec/obidos/tg/detail/-/0133708756/) (1995), and [Hackers & Painters](http://www.amazon.com/exec/obidos/tg/detail/-/0596006624/) (2004). In 1995, he and Robert Morris started Viaweb, the first SaaS company, which in 1998 [became](http://docs.yahoo.com/docs/pr/release184.html) Yahoo Store. In 2002 he discovered a simple spam filtering algorithm that inspired the current generation of filters. He has an AB from Cornell and a PhD in Computer Science from Harvard.
Jessica Livingston
Founder, Retired
Jessica Livingston was previously VP of marketing at investment bank Adams Harkness, where she managed an award-winning rebranding of the company. She is the author of [Founders at Work](http://www.amazon.com/gp/product/1590597141) (2007), a book of interviews with startup founders. She has a BA in English from Bucknell.
Robert Morris
Founder, Retired
Robert Morris is a professor of computer science at MIT, where he is a member of the [PDOS](https://pdos.csail.mit.edu/) group. He has published extensively on wireless networks, distributed operating systems, and peer-to-peer applications. In 1988 his discovery of buffer overflow first brought the Internet to the attention of the general public. He has an AB and PhD in Computer Science from Harvard.