Who We Are: Oasys International LLC (Oasys) is a fast-growing federal government contractor delivering high-quality technology consulting and professional services to civilian, defense, and homeland security agencies. We have been recognized on Inc. 5000’s list of the fastest-growing companies in America for five consecutive years and named a Best Places to Work in Virginia for the past two years.

Our success is driven by a talented team of technologists, consultants, engineers, and subject-matter experts who support complex federal missions with integrity and excellence. At Oasys, we foster a collaborative, merit-based culture that values continuous learning, professional growth, and work-life balance. We are committed to creating an inclusive, engaging environment where employees are recognized for their contributions and empowered to build meaningful, long-term careers.

NOTE: This role is contingent on the contract being awarded.

Position Summary:

The Senior Full-Stack Engineer position requires a highly experienced system engineer with a strong emphasis on backend systems design, architecture, and performance. The role is responsible for leading the development of scalable, secure, and high‑availability backend services while contributing to front-end development. Requires the ability to guide architectural decisions in rapidly evolving environments. Position requires collaboration with product, engineering, and DevOps teams to deliver robust end‑to‑end solutions that power mission‑critical applications.

NOTE: This role is contingent on the contract being awarded.

Primary Responsibilities

• Lead backend architecture and development, ensuring reliability, scalability, and high performance.
• Design and build RESTful and/or GraphQL APIs supporting complex business logic.
• Develop and maintain distributed systems, microservices, and backend services.
• Collaborate with front-end engineers to integrate APIs, ensure data consistency, and deliver seamless full‑stack features.
• Write clean, maintainable, well‑tested code across the stack.
• Conduct in-depth code reviews, provide technical mentorship, and drive engineering best practices.
• Optimize systems for performance, observability, monitoring, security, and fault tolerance.
• Work closely with DevOps teams to build and maintain CI/CD pipelines, deployment workflows, and cloud-based infrastructure.
• Participate in architectural reviews, technical planning, and roadmap discussions.

Skills and Qualifications:

• Bachelor’s degree in computer science or a technical field
• 10+ years developing complex support applications with proven leadership in legacy software rebuilds
• Microsoft Full-Stack Development building web applications using MEAN stack (MongoDB, Express.js, Angular, Node.js)
• Front and back-end development knowledge in JAVA, HTML, CSS, Javascript, and framework libraries expertise
• Solid understanding of API security, caching strategies, and authentication techniques.
• Hands‑on experience with AWS cloud services and containerization (Docker, Kubernetes).
• Strong expertise in database design and management
• Excellent communication and management skills.

Certifications Required:

• Certified Scrum Master
• Certified Professional in Full Stack Development (CP-FSD)

Certification Preferred:

• AWS Solutions Architect certification

Security Clearance Requirements:

• Must be a U.S. Citizen
• Must have an active DoD Secret clearance.

Work Location:

• Fairfax, VA – Corporate Headquarters (Hybrid)

Oasys is proud to be an equal opportunity employer for all protected groups, including protected veterans and individuals with disabilities.