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

About the role

Millennial Software is seeking a Junior‑Mid level Backend Software Developer to join a collaborative team supporting National Security. The role focuses on designing, developing, and supporting scalable APIs and services that power data‑driven applications and enable mission‑critical decisions. The developer will work on backend architecture, data modeling, integrations, performance, and reliability while partnering with frontend engineers, analysts, and users.

Responsibilities

• 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.

Requirements

• Demonstrated experience building and operating production backend services and APIs.
• Proficiency in at least one backend language (e.g., Python, Java, Go, C#, Node.js) and common frameworks.
• Strong understanding of API design, authentication/authorization concepts, and service reliability.
• Experience with relational and/or NoSQL databases, query optimization, and schema/data modeling.
• Experience with messaging and queuing platforms such as Kafka, RabbitMQ, or similar.
• Familiarity with testing strategies and CI workflows; comfort with debugging and incident triage.
• Ability to collaborate cross‑functionally and communicate technical decisions clearly.
• Experience creating and maintaining Docker containers, Helm charts, orchestration platforms such as Kubernetes, and using cloud infrastructure services (AWS/Azure/GCP).
• Bachelor’s degree in a related field or equivalent practical experience.
• 2–10 years performing backend software engineering.
• Active TS/SCI clearance.
• Willingness to work on‑site in Virginia (Fairfax, Chantilly, McLean, Sterling) or Colorado (Colorado Springs).

Preferred Qualifications

• Experience designing distributed systems (caching, queues, streaming, idempotency, retries, circuit breakers).
• Observability experience: metrics, logging, tracing; familiarity with SLOs/SLIs and incident response practices.
• Experience with data pipelines, ETL/ELT, or search platforms.
• Knowledge of security best practices (threat modeling, secrets management, secure SDLC).
• Experience with performance testing and capacity planning.

Benefits

• 100% company‑paid medical, dental, and vision premiums for you and all dependents.
• Ability to receive increased salary if you do not need medical/dental/vision coverage.
• 100% company‑paid disability and life insurance.
• 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.

Pay

$95,000 – $180,000 annually