Backend Software Engineer - GenAI

About Rune

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.

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

• 6+ 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.
• Experience deploying software to production environments, including cloud (AWS, Kubernetes) and edge infrastructure.

Benefits

Rune offers top-tier benefits for full-time employees to include a full suite of insurance options at no cost for employees and low-cost to spouses and dependents. Highly competitive equity grants are also included in the majority of full time offers and are considered part of Rune's total compensation package. Benefits include:

• Comprehensive medical, dental, and vision plans; premiums 100% covered by Rune for all employees; exceptionally low premiums for spouses and dependents
• Basic life insurance and disability 100% covered for all employees by Rune; option to purchase additional life insurance available
• ‘Take the time off that you need, when you need it’ paid time off, not accrual based
• Generous company holiday calendar including a holiday shutdown in December
• Supportive leave of absence program including time off for military service, medical events, and parental leave
• Full 401(k) retirement plan for all full-time eligible employees
• Company-funded commuter benefits
• Free access to on-site gym at office