Senior Software Developer (TS/SCI)

Marathon TS; Springfield (VA); On-site; USD 140,000 - 190,000; Full time

Job summary

Marathon TS is seeking an experienced Senior Software Developer to support intelligence missions in Springfield, VA. The role emphasizes AI development, secure software delivery, and collaboration in a government environment.

The successful candidate will have a TS/SCI clearance, strong Python/Java/Scala skills, and experience with REST APIs, Docker/Kubernetes/OpenShift, and DevSecOps in cloud-native contexts.

Qualifications

• 8+ years of experience in software development and secure apps.
• Degree or equivalent IT experience in relevant fields.
• Strong Python/Java/Scala programming background.
• Experience with RESTful APIs and modern delivery practices.
• Hands-on with containerization and cloud-native architectures.
• Experience with Generative AI tech and LLM workflows.
• Familiar with DevSecOps, security scanning, and hardening.

Responsibilities

• Design, develop, evaluate, plan and test AI features.
• Integrate multiple data streams into customer systems.
• Lead cloud migrations across platforms.
• Develop AI features for Ontology-based apps.
• Collaborate in an agile scrum, participate in ceremonies.
• Write backlog items and support product backlog refinement.
• Apply DevSecOps and secure software development practices.
• Develop and modify apps, services, and IT systems.

Skills

Senior software development

Python

Java

Scala

REST APIs

Agile/Scrum

Generative AI

LLMs

DevSecOps

Cloud-native

Education

Bachelor's Degree in CS/CE/SE or related

6 extra years IT experience

Tools

Docker

Kubernetes

OpenShift

Helm

Git

CI/CD

Job description

Marathon TS is seeking an experienced and collaborative Senior Software Developer to join our team and support one of our intelligence customers in Springfield, VA. The ideal candidate is a self-starter with strong AI development experience who thrives in a mission-focused environment and enjoys solving complex technical challenges.

This position requires an active TS/SCI security clearance and offers the opportunity to work on innovative AI solutions supporting critical intelligence missions. The successful candidate will bring strong technical expertise, a collaborative mindset, and the ability to deliver high-quality solutions in a secure government environment.

Job Summary:

Designs, develops, evaluates, plans and tests AI features across a few software programs and applications

Job Duties:

• Integrate multiple data streams into customer system
• Complete Cloud platform migrations (between currently existing and available platforms)
• Develop AI features for existing Ontology-based software applications
• Creates sustainable software applications – work is estimated accurately, branching strategies are efficient, code repos are maintained, etc.
• Works as a member of an agile scrum team and participates in regular agile ceremonies applying scrum methodologies – daily stand up, planning, sprint reviews, demos, retrospectives.
• Implements requirements from the product backlog
• Assists in writing backlog requirements/user stories
• Utilizes a modern DevSecOps approach in building software applications
• Develop and modify applications, software, services, utilities, interfaces, and IT systems that support systems and analysts.

Required Skills/Qualifications:

• 8+ years of experience
• Bachelor's Degree in computer science, computer engineering, systems engineering or any related field/major, or 6 additional years of experience in information technology.
• Senior-level software development experience designing, developing, and maintaining secure, scalable, and mission-focused applications.
• Strong programming experience with Python, Java, and Scala.
• Experience developing and integrating RESTful APIs, Git-based workflows, automated unit/integration/system testing, CI/CD pipelines, and modern software delivery practices.
• Hands‑on experience with Docker/containerization, microservice architectures, Helm, and development container environments.
• Experience developing applications using Generative AI technologies, including Retrieval-Augmented Generation (RAG), Large Language Models (LLMs), and LLM-enabled workflows.
• Experience designing, deploying, and supporting cloud-native applications using AWS, OpenShift, and Kubernetes.
• Experience integrating, transforming, and managing data from multiple sources, organizations, and network environments.
• Experience deploying applications into new or complex network environments.
• Experience applying DevSecOps practices, including secure software development, code hardening, dependency/package updates, vulnerability remediation, and automated security scanning.
• Ability to troubleshoot complex software systems and collaborate across development, infrastructure, security, and mission teams.

Desired Skills/Qualifications:

• Familiarity with data normalization, transformation, and visualization techniques.
• Familiarity with graph-based data models, data relationships, and advanced data structures.
• Experience working in Agile/Scrum development environments.
• Experience developing and presenting technical metrics, status reports, and project updates to internal leadership and external customers.
• Demonstrated ability and willingness to mentor junior developers and contribute to team engineering practices.