Senior Full Stack Engineer

Senior Full Stack Engineer Position Description i3 is seeking a Full Stack Engineer - Senior to support application design, development, integration, and modernization for a major federal transformation program. This senior role develops secure, scalable, cloud-ready solutions and works across the entire stack—front-end, back-end, APIs, databases, and cloud environments. The Full Stack Engineer collaborates with Product, DevSecOps, Cloud, Data, QA, and Migration teams to deliver mission-critical capabilities that meet federal performance, security, and compliance standards. Your Future Duties And Responsibilities Application & API Development Design, develop, and maintain front-end and back-end components for enterprise applications Build and optimize REST APIs, microservices, and system-to-system integrations Ensure code quality, performance, and maintainability across the full stack Cloud-Ready Engineering Develop cloud-compatible services and applications (AWS preferred) Support deployment of pipelines, infrastructure integration, and CI/CD workflows Align application architecture with modernization and cloud migration requirements Technical Leadership & Collaboration Collaborate with Scrum Masters, Product Leads, QA Automation Engineers, Cloud Engineers, and Data Engineers Participate in sprint planning, backlog refinement, technical design reviews, and demos Mentor mid-level engineers and support knowledge-sharing across teams Security, Performance & Compliance Implement secure coding practices, logging, auditing, and data-handling requirements Conduct performance tuning, optimization, and reliability improvements Ensure delivery aligns with federal security standards and program governance Testing & Quality Support Support automated testing and validation of application functionality and integrations Troubleshoot defects across the stack and coordinate with QA to resolve issues Validate readiness for release and major deployment events Documentation & Reporting Develop technical design documents, API specifications, data flow diagrams, and code documentation Maintain full-stack engineering artifacts required for release, sustainment, and audits Provide status updates and technical insights to leadership and cross-functional teams Required Qualifications To Be Successful In This Role Must have an Active Top Secret Security Clearance U.S. Citizenship Bachelor’s degree and 8+ years of experience in software engineering or full-stack development Experience developing both front-end and back-end solutions using modern frameworks Hands-on experience with APIs, microservices, relational and NoSQL databases Experience with CI/CD pipelines, Git, DevSecOps environments, and automated testing Strong ability to troubleshoot issues across the entire stack Excellent communication and documentation skills Preferred Qualifications Experience supporting DOJ, FBI, Intelligence Community, or other national-security programs Experience with cloud-native architectures (AWS strongly preferred) Familiarity with containerization (Docker), orchestration (Kubernetes), or serverless frameworks Experience with performance engineering, load testing, or automated quality pipelines Knowledge of Python, Java, JavaScript/TypeScript, or similar languages used across full-stack systems