Backend Software Engineer — Secure Mission Systems

Backend Software Engineer — Secure Mission Systems Location: Mainly remote, with onsite work in Laurel, Maryland, typically one day every six weeks for team-wide sprint planning. Exact timing may vary based on project needs. Clearance: Active final DoD Secret clearance required This position supports a pending contract opportunity and is contingent upon contract award, with an anticipated start in November 2026. Build Secure Software for a High-Impact Defense Mission Join Rackner to build secure backend services that support mission-planning and decision-support capabilities for a Department of Defense customer. You will take hands-on ownership of APIs, service integrations, data flows, distributed workflows, and automated testing—not simply complete isolated development tickets. The role offers exposure to secure software delivery, geospatial data, containerized applications, and backend services that support AI-enabled capabilities. This is a primarily remote role within the United States. Work will be performed using customer-provided systems, with virtual collaboration across the engineering team and periodic onsite sprint planning in Laurel, Maryland. What You Will Do Design, develop, test, and integrate secure backend services and APIs. Build and maintain backend services using Python, FastAPI, and C#. Develop REST APIs and support service-to-service communication using gRPC. Build asynchronous and distributed workflows using RabbitMQ and Celery. Develop and integrate relational and geospatial data capabilities using PostgreSQL and PostGIS. Containerize and deploy backend services in OpenShift-based environments. Work within GitLab-based development and CI/CD workflows. Apply secure software-development lifecycle practices throughout design, implementation, testing, and remediation. Develop unit, integration, and system-level tests that support software quality and delivery confidence. Investigate defects, failed integrations, security findings, and service issues. Participate in code reviews, technical reviews, vulnerability-remediation efforts, and solution-design discussions. Produce software designs, sequence diagrams, workflow descriptions, and technical documentation. Collaborate with frontend, AI/ML, security, platform, DevSecOps, and customer engineering teams. What You Bring Bachelor’s degree in Computer Science or a related field. At least four years of professional software-development experience. Hands-on experience designing and developing backend services, APIs, or distributed applications. Developing backend software using Python and C#. Building APIs and services with FastAPI. Experience with RabbitMQ, gRPC, and Celery. Working with PostgreSQL and PostGIS. Using GitLab-based development workflows. Developing or deploying software in OpenShift environments. Understanding of secure software-development lifecycle practices. Writing automated unit and integration tests. Ability to clearly explain the systems you personally built, the technical decisions you made, and how your work was tested and delivered. Clear technical documentation and communication skills. Experience That Will Help You Stand Out FastAPI or another Python web framework. RabbitMQ, Celery, gRPC, or similar messaging and service-integration tools. PostgreSQL, PostGIS, geospatial data, or mapping applications. OpenShift, Kubernetes, GitLab CI/CD, or secure container delivery. Defense, mission-planning, decision-support, or other regulated software environments. Integration of backend services with LLM, retrieval-augmented generation, or other AI-enabled components. You do not need to be the deepest expert in every technology listed. Strong backend fundamentals, credible hands-on experience, and the ability to learn within a secure delivery environment matter most. Why Rackner At Rackner, you will build technology that supports critical defense and public-sector missions. This role offers broader ownership across backend engineering, secure d…