Senior Backend Engineer: Secure APIs for National Security

Millennial Software; Chantilly (VA); On-site; USD 180,000 - 210,000; Full time

Benefits offered by this job

Medical, dental, vision 100% paid for

Disability and life insurance paid

401(k) with 15% company contribution

30 days PTO/holidays

Paid parental leave

Training budget

Company swag

Job summary

Millennial Software seeks a Senior Backend Software Developer to join our team supporting National Security. You’ll design, develop, and maintain scalable APIs and services, focusing on backend architecture, data modeling, integrations, performance, and reliability.

You’ll partner with frontend engineers, analysts, and users to deliver secure, high-quality tools for mission environments. The role emphasizes end-to-end lifecycle responsibilities from design to sustainment, with a strong emphasis

Qualifications

• Bachelor’s degree in a related field or equivalent practical experience.
• Minimum 10+ years of backend software engineering experience.
• Proficiency in at least one backend language (Python/Java/Go/C#/Node.js) and frameworks.
• Experience building production backend services and APIs with scalable architectures.
• Strong knowledge of API design, authentication/authorization, and service reliability.
• Experience with relational and NoSQL databases and data modeling.
• Experience with Kafka or RabbitMQ and messaging systems.
• Experience with Docker, Helm, Kubernetes, and cloud platforms (AWS/Azure/GCP).

Responsibilities

• Design, implement, and maintain backend services, APIs, and integrations.
• Develop data models and persistence layers with quality and performance in mind.
• Build reliable service-to-service communication (REST/GraphQL) and messaging patterns.
• Apply secure coding practices and ensure proper authentication/authorization.
• Create and maintain automated tests and participate in code reviews.
• Diagnose production issues and improve reliability via monitoring and runbooks.
• Collaborate with frontend engineers and stakeholders to define contracts.
• Identify bottlenecks and improve performance (latency, throughput).
• Produce technical documentation for systems, APIs, and procedures.

Skills

Backend development

API design

Security practices

Docker

Kubernetes

CI/CD

Data modeling

Education

Bachelor’s degree or equivalent

Tools

Docker

Helm

Kubernetes

AWS

Azure

GCP

Job description

Millennial Software seeks a Senior Backend Software Developer to join our team supporting National Security. You’ll design, develop, and maintain scalable APIs and services, focusing on backend architecture, data modeling, integrations, performance, and reliability.

You’ll partner with frontend engineers, analysts, and users to deliver secure, high-quality tools for mission environments. The role emphasizes end-to-end lifecycle responsibilities from design to sustainment, with a strong emphasis