Software Engineer - TS/SCI with Polygraph

Type of Requisition: Regular Clearance Level Must Currently Possess: Top Secret SCI + Polygraph Clearance Level Must Be Able to Obtain: Top Secret SCI + Polygraph Public Trust/Other Required: None Job Family: Software Engineering Job Qualifications: Skills: Amazon Web Services (AWS), ElasticSearch, Large Language Models (LLMs), Lean Agile, Semantic Search Certifications: None Experience: 10 + years of related experience US Citizenship Required: Yes Job Description: Transform technology into opportunity as a Software Engineer (SME) with GDIT. We are seeking a hands-on software engineer with expertise in designing, developing, and sustaining cloud‑enabled applications in Lean Agile environments to deliver secure, scalable, and maintainable mission‑critical customer systems. The role requires expertise in frontend and backend Web development and modern search engineering technologies, including Large Language Models (LLM), Retrieval‑Augmented Generation (RAG), and AI‑assisted retrieval system capabilities development.

KEY TASKS:

• Participate in all Lean Agile scrums, sprint planning, and grooming sessions.
• Consult and coordinate with stakeholders for problem resolution, task

scheduling, resource needs, and task clarification.

• Work in partnership with an integrated team of staff and contractors.
• Coordinate and collaborate with security, operations, engineering, testing,

and other teams to provide system information and technical support.

• Understand and work within approved cloud environments (e.g., AWS).
• Design, develop, and modify software systems.
• Unit test software and perform code reviews.
• Design and implement scalable search and retrieval systems leveraging

Elasticsearch. * Develop and integrate LLM‑powered capabilities, including Retrieval‑Augmented Generation (RAG) pipelines. * Document and track vendor software roadmaps for software and patch version updates.

REQUIRED SKILLS AND DEMONSTRATED EXPERIENCE:

• Demonstrated experience working in Lean Agile Development environment.
• Demonstrated experience translating customer and system requirements into

actionable design specifications. * Demonstrated experience designing system interfaces, including defining integration points, data flows, and data exchange workflows. * Demonstrated experience building or integrating LLM-based solutions, including RAG pipelines, semantic search, and AI-assisted retrieval systems. * Demonstrated experience designing and implementing data pipelines for hybrid search (BM25 + vector search) in RAG workflows, covering ingestion, chunking, embeddings, and vector retrieval. * Demonstrated experience with Elasticsearch, included index design and optimization, query development, relevance tuning, and cluster scaling. * Demonstrated hands-on experience in frontend Single Page Applications (SPA) development using React (hooks), HTML5, CSS3, and modern JavaScript best practices. * Demonstrated hands-on experience in backend development, including designing and building RESTful APIs with Node.js and Express.js (or comparable modern backend frameworks). * Demonstrated hands-on experience troubleshooting web protocols and server technologies, including Apache Tomcat, Node.js, Web Services, and SSL/TLS security configurations.

• Demonstrated experience using modern testing platforms such as Jest or Karma.
• Demonstrated experience with DevOps tools including Git, Jenkins, and Nexus.

HIGHLY DESIRED SKILLS AND DEMONSTRATED EXPERIENCE:

• Experience with the customer’s Lean Agile methodology.
• Experience evaluating, selecting, or integrating LLMs (e.g., OpenAI,

open‑source models) into enterprise applications. * Experience with vector databases, hybrid search (keyword + semantic), and relevance optimization.

• Experience with or exposure to RAG, LLM integrations, or semantic search.
• Experience with Elasticsearch or similar search platforms, with some exposure

to optimization or scaling. * Experience mentoring teams in search engineering and AI/LLM best practices, with a demonstrated ability to improve overall team capability. * Experience with React + Node/Express development, with the ability to quickly ramp into search/AI domains. * Experience working on APIs or systems that integrate with external AI/ML services. * Demonstrated ability to learn quickly with guidance and become a team multiplier.

WHAT YOU’LL NEED TO SUCCEED:

* Education: Bachelor’s degree in Computer Science, Engineering, or a related technical discipline, or the equivalent combination of education, technical certifications or training, or work experience.

• Experience: 10+ years
• Security clearance: TS/SCI with Polygraph
• Location: Chantilly, VA (On Customer Site)
• US Citizenship Required

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#JET

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The likely salary range for this position is $158,855 - $214,921. This is not, however, a guarantee of compensation or salary. Rather, salary will be set based on experience, geographic location and possibly contractual requirements and could fall outside of this range. Scheduled Weekly Hours: 40 Travel Required: Less than 10% Telecommuting Options: Onsite Work Location: USA VA Chantilly Additional Work Locations: Total Rewards at GDIT: Our benefits package for all US-based employees includes a variety of medical plan options, some with Health Savings Accounts, dental plan options, a vision plan, and a 401(k) plan offering the ability to contribute both pre and post-tax dollars up to the IRS annual limits and receive a company match. To encourage work/life balance, GDIT offers employees full flex work weeks where possible and a variety of paid time off plans, including vacation, sick and personal time, holidays, paid parental, military, bereavement and jury duty leave. To ensure our employees are able to protect their income, other offerings such as short and long-term disability benefits, life, accidental death and dismemberment, personal accident, critical illness and business travel and accident insurance are provided or available. We regularly review our Total Rewards package to ensure our offerings are competitive and reflect what our employees have told us they value most. Our Identity Verification Process: As part of the hiring process, we will ask you to complete an identity verification process that leverages advanced biometrics and artificial intelligence to ensure authenticity and protect against identity fraud. You are expected to be on camera during virtual interviews. We reserve the right to take your picture to verify your identity and prevent fraud. By proceeding, you authorize the collection, processing, and use of your biometric data for identity verification and security purposes. About Our Work: We are GDIT. A global technology and professional services company that delivers technology solutions and mission services to every major agency across the U.S. government, defense and intelligence community. Our 26,000 experts extract the power of technology to create immediate value and deliver solutions at the edge of innovation. We operate across 50+ countries worldwide, offering leading mission-ready capabilities in AI, cloud, cyber and software development. Join our Talent Community to stay up to date on our career opportunities and events at gdit.com/tc [ Equal Opportunity Employer / Individuals with Disabilities / Protected Veterans