Dennis Yu

← All the people Dennis builds with

Friend · Co-founder and running partner

Dennis Yu and Chris Rummel after finishing the 2001 Portland Marathon, medals around their necks
Dennis and Chris after the 2001 Portland Marathon. This is the photo in the library — the two of them, still in the finisher shirts.

Chris Rummel

Chris Rummel was Dennis’s close friend and co-founder. They were engineers at Yahoo. Every Tuesday and Thursday they played ultimate frisbee. They ran marathons together. The picture above is them after Portland in 2001.

They built a software company. Run data, heart rate, and nutrition adjusted the training plan automatically — before the current wave of AI tools. They studied physiology journals, not magazines. Professional athletes endorsed it. Hal Higdon and the Chicago Marathon community agreed to use it.

Chris was a flight instructor at Embry-Riddle. He was getting married and needed money. Dennis withdrew $20,000 from Bank of America that afternoon. Chris was too proud to take it as a gift. He insisted on selling Dennis his Volkswagen GTI. Dennis did not want the car. Chris then rode his motorcycle to work.

Chris died after a motorcycle accident in Mountain View. Dennis has said he never forgave himself for not fighting harder, and that a voice had warned him weeks before.

When Dennis tried to honor Chris by releasing the software, the code was locked behind Chris’s credentials. Undocumented work died with the person. That is why Dennis builds in public now.

When Dennis watches Trenton Sandler build in public with Grant, he sees what he and Chris had, done smarter.

Dennis Yu and Chris Rummel in a close airport selfie, gate chairs behind them
Dennis and Chris, somewhere between gates. The kind of photo you take because you are just glad to be on the same trip.
Chris Rummel and Dennis Yu in a booth, hands up as antlers, Chris in a Dallas Star-Telegram shirt
An older print. The two of them being idiots in a booth. Chris is in the Dallas Star-Telegram shirt.
Chris Rummel at the top of a golf backswing, face down toward the ball
Chris on a course. His face is down on the swing — still a real photo of him.

The Tuesday and Thursday frisbee shots are still not in this set. These are the photos that were.

Already written

This page is part of how Dennis Yu honors the people he builds with — real pages that link real work, so the people he believes in rank on their own names. Meet the rest →

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