Yulia Startsev is a programmer on the SpiderMonkey compiler at Mozilla. She served as a chair for Ecma's TC39, the committee responsible for design and development of the JavaScript language. She initiated and co-facilitates the TC39 research group, which evaluates and applies recent academic research to the development of language features. She is a co-chair of PLSS, a workshop dedicated to exploring scientific research in programming language design and specification. Her work focuses on bringing evidence-based reasoning to technical decision making in language communities.