Principal Software Engineer

About Legion Let’s be real, AI isn’t magic; Legion was built to move beyond AI hype—delivering secure, reliable systems that work alongside the people tackling the world’s most critical challenges. Born from a Department of Defense partnership and trusted by leaders across government and enterprise, Legion embeds intelligence inside complex systems, unlocking data, accelerating human workflows, and strengthening mission-critical systems. We don’t replace workflows—we optimize them, ensuring quality, efficiency, and reliability inside the platforms our partners already use. With world-class collaborators like Palantir, Nvidia, HPE, and Oracle, we’re building intelligent infrastructure that enhances human capability and drives impact at the edge and across a range of enterprises. We’re looking for bold thinkers and doers to join us in shaping the future of AI that’s secure, grounded, and built to work. Principal Rust Engineer - Platform (Remote USA) ***US Citizenship or Greencard is required due to US Government contract requirements*** ***This role requires expert level RUST programming language experience*** Job Summary: As a Principal Software Engineer, you will play a primary role in developing and maintaining the core infrastructure that underpins our AI platform. Your expertise in coding and architecture will be instrumental in building out core platform features, while your proficiency in Rust will enable you to contribute to the growth of our technology stack. Your experience with production support, Kubernetes, and Docker will ensure the platform's stability and reliability. Responsibilities: Design and develop foundational components and frameworks that serve as the building blocks for our Agentic AI platform. Collaborate with cross-functional teams to understand their needs and requirements, and create platform solutions that empower developers to build innovative applications on top of it. Cultivate a growth mindset, constantly studying and staying current with design patterns, techniques, and technologies that attract developers to platforms and frameworks. Work closely with machine learning engineers to build the infrastructure that supports ML workflows, ensuring seamless and efficient execution within enterprises. Provide production support and troubleshooting expertise to ensure the platform's smooth operation and address any performance or scalability challenges. Required Skills and Qualifications: US Citizenship or Greencard is required due to US Government contract requirements Bachelor's degree in Computer Science, Software Engineering, or a related field or equivalent experience. 15+ years of software and platform engineering experience, with a strong track record of designing and operating large-scale distributed systems. Experience building platform infrastructure and backend systems that serve multiple products and engineering teams. Experience in Rust, with expertise in designing and developing high-performance systems. All our performance-critical areas are developed in Rust. Demonstrated expertise in database architecture and scalable data systems, including distributed databases, storage and indexing systems, data modeling and schema design, high-throughput and low-latency data access patterns. Experience designing systems that support AI and machine learning workloads Familiarity in workflow engines, execution runtimes, and AI orchestration frameworks Growth mindset and low ego- you’re eager to pick up new tools and technologies, learn from others, and be open to changing course when it’s right. Drive to foster a culture of collaboration, psychological safety, and technical excellence. Strong advocate for inclusion in technical discussions at all levels. Preferred Qualifications: Start-up experience or comfort in 0→1 product environments. Familiarity with Kubernetes is a plus. Understanding of DevOps practices and CI/CD pipelines for platform deployment. Compensation Information $2,300,000 - $3,000,000 USD Equal Opportunity Statement Legion provides equal employment opportunities to all employees and applicants for employment and prohibits discrimination and harassment of any type without regard to race, color, religion, age, sex, national origin, disability status, genetics, protected veteran status, sexual orientation, gender identity or expression, or any other characteristic protected by federal, state or local laws.