Application developer with Security Clearance

Job Title: Application Developer Location: Reston, VA Clearance: TS/SCI with Full Scope Polygraph (Required) Company: Quantum Science Solutions (QSS) Compensation: Open Rate Position Overview Quantum Science Solutions (QSS) is seeking a cleared and local Application Developer to support a mission-critical federal program in the Reston area. This role involves maintaining existing legacy applications and assisting in the transition to a modernized system architecture that enhances enterprise performance, scalability, and security. The successful candidate will bring strong full-stack and backend development expertise, proficiency in Java, RDBMS support, and a solid understanding of API creation and integration. This position requires hands-on technical problem-solving and close collaboration within Agile teams to deliver high-quality, secure, and reliable solutions. Key Responsibilities • Maintain, enhance, and support legacy applications while facilitating transition to new architecture. • Develop and maintain backend services, APIs, and data integrations. • Provide RDBMS (Relational Database Management System) support including performance tuning and data modeling. • Utilize Java for backend development and support system modernization efforts. • Apply strong troubleshooting and problem-solving skills to address issues across all application layers. • Collaborate within an Agile/Scrum environment alongside developers, testers, and system engineers. • Document technical system architecture and application design. • Manage source code using Git (GitHub, GitLab, etc.). Mandatory Skills • Minimum 5 years of experience in Full Stack Development. • Minimum 3 years of demonstrated RDBMS support experience. • Proven Java development experience. • Strong troubleshooting and debugging skills. • Demonstrated experience in backend development and API creation. • Experience working within an Agile development environment. • Ability to document technical system architectures and processes. • Proficiency with Git (e.g., GitHub, GitLab). Preferred Skills • Experience with C# and legacy system development. • Experience integrating applications with Geographic Information Systems (GIS). Education • Bachelor’s degree in Computer Science, Computer Engineering, Computer Information Systems, Computer Systems Engineering • Equivalent experience may be substituted on a year-for-year basis. Why QSS? At QSS, you’re not just filling a role, you’re shaping mission-critical solutions that keep our nation secure. We invest in your growth, foster innovation, and reward technical excellence. Benefits include: • Competitive compensation with annual performance bonuses • Premium Medical, Dental & Vision coverage • Generous PTO plus Federal Holidays • 401(k) with company match • Opportunities for continuous learning and skill development