This position is listed on behalf of a partner company, who manages all applications and next steps. Our partner is looking for a Principal UX Engineer, Ads based in the United States. This is a strategic, hands-on leadership role at the intersection of product design and engineering.You’ll use code as a design medium to prototype ideas, test assumptions, and shape product direction.You’ll work across advertising products and experiences, partnering with Design, Research, Product, Engineering, and Data Science.The role combines deep technical craft with systems thinking, enabling teams to move from concepts to polished products faster.You’ll establish reusable tools, components, and workflows while raising the bar for accessibility, performance, and interaction quality.You’ll also explore how AI can transform both advertising experiences and the way product teams design and build.As a principal-level contributor, you’ll influence multiple product areas, mentor others, and help define the future of UX Engineering.