Senior Full-Stack Design Engineer

ABOUT THE ROLE Join a product team at an early-stage AI infrastructure startup to design and build interfaces for tools used to create and evaluate AI agent environments. You will work across product design and front-end engineering, making technically complex workflows clear and actionable while helping shape how people work with AI systems. WHAT YOU'LL DO - Design and build product interfaces from early concepts through release. - Make agent runs, evaluation results, reward signals, and quality feedback understandable and useful. - Partner with research and engineering to turn reinforcement learning and evaluation workflows into practical tools. - Talk with users, identify where they struggle, and improve the product based on feedback. - Create reusable interaction patterns and maintain strong usability, visual quality, and implementation standards. WHAT WE'RE LOOKING FOR - At least 3 years of experience in design engineering, product design, or a similar role shipping product interfaces. - Hands-on front-end engineering skills and experience turning designs into working interfaces. No specific programming stack is listed. - A portfolio of shipped design engineering work and a track record of learning from user feedback. - Experience working closely with engineers and researchers on product development. - Strong product and interaction design judgment, clear communication, and comfort working with technical concepts. - Experience with developer tools, data-rich products, research software, AI agents, evaluations, reinforcement learning, or training data is valuable. COMPENSATION & BENEFITS Annual salary range: $130,000 to $225,000. Visa sponsorship is available. LOCATION Based in San Francisco, California. The role may be on-site or remote.