Software Engineer, Horizon

Sierra is seeking a Software Engineer for the Horizon team to build primitives for self-improvement, design long-horizon agents across voice/SMS/email, turn 0-to-1 work into reusable platform, solve complex technical problems, shape the Horizon product, and create clean paths beyond POC. The role involves working with customers and building end-to-end production systems.

Required: Experience building and scaling end-to-end production systems, strong platform and systems engineering fundamentals, ability to move between customer problems and technical implementation, strong technical judgment in ambiguous environments, builder's mindset, comfort working directly with customers, high agency, at least two years professional software engineering experience, and experience with Python, TypeScript, or Go and React.