Backend Software Engineer - Simulations

About Rune Rune Technologies builds mission-critical software for military logistics and sustainment. Our flagship product is TyrOS, an AI-enabled logistics command and control platform that gives commanders a single, real-time operating picture of their sustainment fight, from inventory and distribution to medical and operational planning, even in degraded and contested environments. We're not a traditional defense contractor. We're a small, fast-moving team that combines deep operational experience in and with the DoD with the software discipline of the best product companies, and we apply that combination to a customer set that desperately needs it. We stay close to our users by embedding directly with military units during exercises and rotations, and we ship constantly based on what we learn. The U.S. military and its allies face a real logistics modernization problem. We're building the software to solve it. About the Role At Rune Technologies, we are building the logistics technology backbone that the U.S. and allied militaries need to dominate in large-scale combat operations. As a Backend Software Engineer at Rune, you will be part of a high-impact team working at the intersection of advanced logistics algorithms, modern AI-enabled software, and complex system integrations — all in support of the warfighter at the tactical edge. You'll join us in our mission to bring 21st-century software to the sustainment domain: modernizing inventory management, transportation optimization, and predictive planning with state-of-the-art user experiences. You'll work closely with a team of experienced engineers, product designers, and operational experts who care deeply about delivering real-world impact. As our Backend Software Engineer for Simulations, you will own the simulations workstream within TyrOS, working closely with our forecaster lead and the broader platform team. The primary focus is Rune's forecasting system, building the production software that models, predicts, and reasons about logistics outcomes in complex operational environments. This role calls for a strong software engineer who is also mathematically and scientifically fluent: someone who can work in formulas, reason about physical systems, and build production-quality software around that reasoning. What You'll Do - Build and own production-grade simulation and forecasting software, with a primary focus on Rune's logistics forecaster. - Work with mathematical models, numerical methods, and scientific formulas to implement software where correctness is defined by the underlying physics or math, not just user acceptance. - Collaborate closely with the forecaster lead and platform team to integrate simulation capabilities into TyrOS workflows. - Participate in technical design discussions and code reviews, contributing to a culture of engineering rigor and mission focus. - Triage and debug issues in production, ensuring reliability and rapid iteration in support of operational needs. - Work closely with engineers, product managers, and military stakeholders to ensure simulation and forecasting systems meet real-world sustainment requirements. Qualifications - 4+ years of experience in software engineering, with demonstrated experience building software in a scientific or mathematically complex domain: sensor algorithms, motion planning, simulation, forecasting, or similar. - Ability to work with mathematical models and numerical methods in code; comfort reasoning about correctness in terms of physics or math, not just software behavior. - Proficiency in Python, C++, or Go. - Strong software engineering foundation - this role requires production-quality engineering, not analysis or research. - Math or science background, through degree, graduate work, or professional domain experience. - Strong sense of ownership and a bias for action. Desired Qualifications - Experience at a defense-adjacent autonomous systems company in a hands-on engineering capacity - Degree