Secure Full-Stack Dev (TS/SCI) – On-Site

Sphinx LLC; Springfield (VA); On-site; USD 140,000 - 190,000; Full time

Job summary

Sphinx is seeking a Full-Stack Software Developer (Contingent) to design, develop, and maintain mission-critical applications for a federal counterintelligence customer in a classified environment. This hands-on role spans front-end interfaces, back-end services, and data layers, requiring secure, scalable tools and zero-trust considerations. Starting TBD, contingent on contract award.

Requires TS/SCI with CI Poly, U.S. citizenship, and DoD 8140 compliance; on-site in Springfield, VA.

Qualifications

• Active TS/SCI clearance with a current CI Polygraph (within the last 5 years).
• U.S. Citizenship (required for clearance eligibility)
• BS in Computer Science or a related field
• 8+ years of software development experience across the full stack
• DevSecOps and CI/CD pipeline experience
• Secure coding experience (OWASP, NIST 800‑53)
• DoD 8140 compliance — CompTIA Security+ or equivalent

Responsibilities

• Design, develop, and maintain full-stack applications in a classified environment
• Build responsive front ends (React, Angular, Vue) and back‑end services (Python, Java), and integrate the two
• Deploy and manage containerized applications
• Build and maintain DevSecOps and CI/CD pipelines for secure continuous delivery
• Apply secure coding practices aligned to OWASP guidelines and NIST 800‑53 controls
• Architect and implement Zero Trust network and application design
• Partner with program security officers, data engineers, and mission stakeholders to translate requirements into working software

Skills

Active TS/SCI clearance

U.S. Citizenship

BS in Computer Science

8+ years full-stack

DevSecOps

Secure coding

DoD 8140 compliance

Education

BS in Computer Science or related field

Tools

Terraform

Ansible

Kubernetes

CI/CD tooling

Job description

Sphinx is seeking a Full-Stack Software Developer (Contingent) to design, develop, and maintain mission-critical applications for a federal counterintelligence customer in a classified environment. This hands-on role spans front-end interfaces, back-end services, and data layers, requiring secure, scalable tools and zero-trust considerations. Starting TBD, contingent on contract award.

Requires TS/SCI with CI Poly, U.S. citizenship, and DoD 8140 compliance; on-site in Springfield, VA.