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Meet William Stein.

William Stein with his dog, Bella.
William Stein, CEO & Founder
Chief Executive Officer and Founder of SageMath, Inc.
William is both the CEO and a lead software developer for both the front and back end of CoCalc. His involvement with SageMath development is a testament to his dedication and commitment. His remarkable past career, including a tenure as Professor of Mathematics at the University of Washington, adds depth to his leadership.
A Passionate CEO and Founder
In his role as CEO of SageMath, Inc., William is at the helm, navigating the future of CoCalc. His responsibilities span delegating tasks, driving profitability, and managing the company’s overall growth strategy. In addition, he maintains a close eye on developments within the cloud-based software industry, assesses company risks to ensure they’re minimized, and ensures that CoCalc remains stable and productive.


William’s academic journey began at the University of California, Berkeley, where he dedicated immense time and energy to using closed-source software like Magma for in-depth analysis and research. Though an admirer of its powerful underlying algorithms, William yearned for more transparent software that didn’t operate as a “black box.” His wish to understand "how things operate under the hood" eventually led him to develop SageMath during his time as Assistant Professor of Mathematics at Harvard.
April 2013 marked another momentous chapter in William’s professional life: he launched SageMathCloud, now known as CoCalc. Inspired by his experiences in the academic and computational fields, this web application was designed to enable the collaborative use of open-source software (while eliminating typical installation and package maintenance issues), thus enhancing the teaching and research process in mathematics and data science. CoCalc now operates under a corporate model, making it self-sufficient and capable of growth independent of grants or other external funding.
William’s not all business either. You can catch him making the most of Seattle’s famously dismal winters by splitboarding with his Blue Heeler Bella in the Cascades or skating vert at "the most rad private ramp in Seattle."
Here is his personal website.

Previous Experience

  • University of Washington · 2006-2019

    Tenured Professor of Mathematics
  • University of California San Diego · 2005-2006

    Tenured Associate Professor of Mathematics
  • SageMath Open-Source Software · 2004

  • Harvard University · 2000-2005

    Assistant Professor of Mathematics
  • University of California Berkeley · 1995-2000

    Ph.D. in Mathematics