About

I’m Samuel Zeng — product leader, recovering mathematician. I have a PhD in Mathematics from the University of Rochester, where I spent five years studying things that turned out to be useful in ways I didn’t expect.

My career has been a series of bets on hard problems in fast-moving markets. I joined Didi when the international expansion was just a whiteboard idea, spent years building ride-hailing from zero in Brazil, Mexico, and Colombia — getting to roughly 30% market share. Then I moved to Kuaishou to run Brazil as GM, growing daily actives from 10 million to 30 million.

I’m now at Trip.com Group as Product Director for the Trip.com overseas flight business, and serve as CPO of Travix, Trip.com’s European flight booking subsidiary.

How I think

Math trained me to find the simplest model that explains the most. That instinct transfers directly to product work: most problems look complex on the surface but have a small number of variables that actually drive the outcome. Find those, move them.

I’m an AI practitioner, not just an enthusiast. I’ve shipped AI check-in products, built AIGC content pipelines, and in my personal time, built several AI applications from scratch — a travel planning agent, a stock monitoring system, an accounting tool. I write my own code. The products are sharper for it.

Outside work

I’ve traveled to 30+ countries and lived on three continents — five years in the US (Rochester, then the Bay Area), three years in Brazil, one in Mexico. The accumulation of drastically different environments changed how I reason about almost everything: what people want, how organizations fail, why some places are poor and others aren’t.

I take photographs and study the night sky. Photography slows down the way I look at places. Stargazing is the only hobby I have that reliably puts problems in proportion.

This site

I use this as a place to think in public — longer-form writing that doesn’t fit character limits elsewhere. If you want to see what I’m working on right now, check the Now page.