Junior-Mid Backend Software Engineer, TS/SCI with CI Poly - $95K-$180K + 15% 401k

About Millennial Software:

Millennial Software is revolutionizing the landscape of security and defense by leveraging our core competencies in software development, automation, DevSecOps, and machine learning.

• 100% company-paid medical, dental, and vision premiums for you and all dependents
• Ability to get increased salary if you don't need medical/dental/vision
• 100% company-paid disability and life insurance benefits
• 15% 401(k) company contribution
• 30 days of PTO/holidays
• Generous training budget
• Paid Paternal and Maternal Leave
• Business development / growth incentives
• Top notch company swag

Job Description:

Millennial Software is seeking a Junior - Mid level Backend Software Developer to join our collaborative team supporting National Security. You’ll design, develop, and support scalable APIs and services using a tech stack that power data-driven applications and enable mission-critical decisions. You will focus on backend architecture, data modeling, integrations, performance, and reliability while partnering with frontend engineers, analysts, and users.

The ideal candidate is passionate about the full lifecycle—design, coding, testing, deployment, and sustainment—and comfortable delivering secure, high-quality tools in mission environments.

Essential Functions:

• Design, implement, and maintain backend services, APIs, and integrations that support product features.
• Develop data models and persistence layers; ensure data quality, integrity, and performance.
• Build reliable service-to-service communication and integration patterns (REST/GraphQL, messaging, streaming).
• Apply secure coding practices and ensure appropriate authentication/authorization patterns.
• Create and maintain automated tests (unit/integration) and participate in peer code reviews.
• Diagnose and resolve production issues; improve reliability through monitoring, alerting, and runbooks.
• Collaborate with frontend engineers and other stakeholders to define contracts and support end-to-end delivery.
• Identify bottlenecks and drive performance improvements (latency, throughput, resource utilization).
• Produce technical documentation for systems, APIs, and operational procedures.