Square co-founder Tristan O’Tierney, who built the company’s first mobile app, dead at age 35

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Square cofounder Tristan O’Tierney died Feb. 23 at age 35 from causes relating to addiction, the San Francisco Chronicle reported.
O’Tierney, who worked at Square from 2009 to 2013, built the original iPhone app at Square, the mobile payments company.
In the last years of his life, he pursued photography as a hobby and for work, traveling around the world and sharing his work on Instagram.
Here’s what people are saying on Twitter.

Square co-founder Tristan O’Tierney, who develop Square’s original mobile payment app, passed away Feb. 23 in Ocala, Florida at age 35, the San Francisco Chronicle reported.

O’Tierney joined Square in February 2009 and built the original iPhone app as the head developer. He was the third co-founder of Square alongside Jack Dorsey and Jim McKelvey. Prior to that, O’Tierney had worked at companies like VMware, Apple, and Yahoo. O’Tierney left Square in June 2013.

Since leaving Square, he has done freelancing app development, worked as Director of Mobile for Voteraide, and pursued photography. He spent time traveling and doing photography both as a hobby and as a freelancer.

O’Tierney’s family told San Francisco Chronicle that he died from causes relating to addiction, and they are awaiting an official cause of death from officials. He had been battling addiction for three years and was in a three-month rehabilitation program in Ocala, his mother Pamela Tierney told the Chronicle. O’Tierney had previously shared some of his struggles with addiction on social media.

A memorial service for O’Tierney will take place in San Francisco in the next two to three weeks.

Business Insider has reached out to Square for a statement. Square’s website does not mention O’Tierney.

As an avid photographer, O’Tierney often posted his work on Instagram. Below is O’Tierney’s last image he posted on his Instagram, taken in Kailua-Kona, Hawaii.

Here’s what people have been saying on Twitter.

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