Backend Software Engineer - Saga

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 maintenance 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 a Backend Software Engineer focused on Saga -- Rune's AI agentic layer within TyrOS -- you will own the design and implementation of production GenAI systems that bring intelligent, autonomous capability to the sustainment domain. This is a backend engineering role first: we're looking for someone who has built real AI systems from the ground up, worked closely with engineers and operational experts, and cares about shipping software that actually works in the field. What You'll Do - Design, build, and deploy production-grade GenAI systems -- including RAG architectures, vector databases, LLM integrations, and tool-call frameworks -- in support of Saga, Rune's AI agentic product layer. - Build and maintain evaluation and testing harnesses to validate LLM output quality and catch regressions in production. - Collaborate with the broader platform and product teams to integrate AI 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 AI systems meet real-world sustainment requirements. Qualifications - 4+ years of experience in software engineering, with a strong backend foundation -- distributed systems, APIs, production-grade software. - Hands-on experience building GenAI systems: vector databases, LLM integration, RAG architectures, and evaluation harnesses for LLM output. - Familiarity with tool routing, tool-call validation, and common LLM failure modes. - Understanding of the science underlying the systems you build -- not just how to wire them together, but why they work and where they break. - Background at an AI-native company, or a clear transition from backend engineering into AI specialization. - Strong sense of ownership and a bias for action. Desired Qualifications - Experience with fine-tuning or model evaluation workflows. - Familiarity with AI infrastructure: embedding pipelines and inference optimization. - Experience working on software in defense, aerospace, or other complex operational domains. - Expe