Senior Full Stack Developer (PostgreSQL, Python, Java, .NET)

ABOUT THE ROLE

Must be a U.S. Citizen with Active TS and eligible for a Top Secret (Tier 5) clearance. No third party. No H1B or Green Card holders.

Strategic Innovation Group (SIG) is seeking a Full Stack Developer to support the design, development, testing, deployment, and maintenance of a secure, scalable data-visualization and AI-enabled analytics application for a federal government client. The application delivers browser-based dashboards, filtering and drill-down, analytic signals, and natural-language search over a centralized PostgreSQL data core, and is built on-premises within the client's FedRAMP Moderate environment. The ideal candidate will work across the full software development lifecycle in an Agile environment, collaborating with the program manager, solutions architect, data engineers, AI/ML engineer, configuration manager, security lead, accessibility partner, and client stakeholders to deliver reliable, mission-focused technology.

ABOUT SIG

SIG is a fast growing 8(a) government contractor based in Arlington, Virginia. We offer a broad range of technical expertise and experience in Digital Transformation, Data Management/Data Science, and Systems Modernization. At SIG, our people are our mission. Come join our team! A successful candidate will be offered the following:

- Great work/life balance
- Eligibility for performance-based participation in cash bonuses
- Potential to participate in growth of the company through incentives
- Excellent benefits, including health, dental, vision, generous PTO, a 401(k) with match, life insurance, short- and long-term disability, and a health savings account (HSA)

RESPONSIBILITIES

- Design, develop, test, deploy, and maintain the browser-based examiner application, including portfolio and program dashboards, filtering and drill-down by type, geography, recipient, agency/program, and status, a consolidated awards-and-signals view, and routine and customizable reports, using React (or Angular) on the front end and Python (FastAPI/Django), Java (Spring Boot), or .NET (ASP.NET Core) on the back end, as directed by the solutions architect.
- Develop RESTful APIs and services over the PostgreSQL data core using JSON, including inspectable, executable dashboard and signal queries that run deterministically without a live AI model.
- Build interactive data visualizations with D3, Plotly, Recharts, or a comparable charting library.
- Integrate the natural-language search and summarization services delivered by the AI/ML engineer (on-premises LLM, retrieval-augmented generation, pgvector or comparable vector store), preserving traceability from every AI output to its source record or document.
- Implement authentication and role-based access control against the client's enterprise identity services (SAML, OAuth 2.0/OIDC, CAS), session management, and audit logging that forwards to Splunk.
- Containerize the application with Docker and deploy through the program CI/CD pipeline (GitLab, Jenkins or Azure DevOps) to the client's Rancher-managed Kubernetes platform, working with the configuration manager on builds, security scanning, and releases.
- Implement automated unit, integration, and API testing (pytest, JUnit, xUnit, Playwright or Cypress) and secure coding standards aligned to NIST SP 800-53 Moderate controls.
- Build exclusively with the program's Section 508-audited component library; perform keyboard/tab-order testing and automated accessibility scans (axe or equivalent) before code review, and remediate accessibility findings within the sprint.
- Troubleshoot and resolve software defects, integration issues, query performance bottlenecks, and production errors.
- Create and maintain technical documentation, system designs, release notes, and operational procedures supporting knowledge transfer to the client's support team.
- Participate in Agile ceremonies, sprint planning, code reviews, demonstrations, user acceptance testing with client staff, and continuous improvement activities.

REQUIRED QUALIFICATIONS

- Bachelor's degree in Computer Science, Engineering, Information Systems, or a related field; equivalent experience may be considered.
- 5+ years of experience as a Full Stack Developer, Software Engineer, or similar technical role (3+ years with a Master's degree).
- Strong PostgreSQL skills, including writing and tuning complex analytic queries, views and materialized views, and designing APIs over relational data.
- Professional experience in at least two of Python (FastAPI, Django, or Flask), Java (Spring Boot), and .NET (ASP.NET Core), with the ability to work in the third.
- Proficiency in a modern front-end framework (React, Angular, or Vue) and a JavaScript charting/visualization library.
- Hands-on experience designing and consuming RESTful APIs and web services using JSON.
- Experience implementing SAML, OAuth 2.0/OIDC, or CAS authentication and role-based authorization.
- Experience with Git-based version control, CI/CD pipelines, Docker, automated testing, and modern deployment practices.
- Working knowledge of Section 508 / WCAG 2.x requirements and accessible front-end development.
- Knowledge of secure coding, data protection, application security, and production support practices.
- Experience working in Agile software development environments and collaborating with technical and non-technical stakeholders in a federal contracting environment.
- Must be a U.S. Citizen and eligible for a Top Secret (Tier 5) clearance.

PREFERRED QUALIFICATIONS

- Experience supporting federal civilian, financial-oversight, budget, or grants-management IT programs.
- Experience deploying to Kubernetes (Rancher preferred) in an on-premises or air-gapped federal environment.
- Experience with Jenkins or Azure DevOps pipelines integrated with GitLab, and with container security scanning.
- Experience integrating LLM, retrieval-augmented generation, or vector-database services into a user-facing application.
- Experience building dashboards or reporting for financial, budget, grants, or oversight users.
- Familiarity with Splunk log integration and NIST SP 800-53 audit-logging and access-control requirements.
- Prior experience supporting mission-critical applications in production environments.
- Active Secret or Top Secret clearance, or prior federal clearance experience.

SIG is an Equal Opportunity Employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, disability, or protected veteran status.