Andrew Bialecki is a co-founder of Klaviyo and has served as a member of our board of directors since September 2012 and as our co-Chief Executive Officer since January 2026. Prior to that, Mr. Bialecki served as our Chief Executive Officer from September 2012 to December 2025. Prior to founding Klaviyo, Mr. Bialecki served as Chief Technology Officer of RockTech, a sales and marketing software company, from April 2011 to June 2012, Senior Engineer at Performable, a marketing software company, from July 2010 to March 2011, and Lead Engineer at Applied Predictive Technologies, a business analytics software company, from September 2007 to June 2010. Mr. Bialecki holds a Bachelor of Arts degree in Physics, Astronomy and Astrophysics from Harvard University.