Sr C#/.NET Developer with Security Clearance

Hybrid (first 60 days on-site then transitions to hybrid)

Clearance: Top Secret (will be processed for SCI and CI Poly after starting)

Location: Washington, DC We are seeking a C# .NET Developer to join our team and support our client in Washington, DC. As a .NET Developer, you will contribute to the development, enhancement, and maintenance of web applications and services that support mission‑critical operations. You will work hands‑on with the .NET framework and associated technologies to build clean, efficient, and reliable backend components that integrate seamlessly with front‑end and cloud‑based systems. In this role, you will collaborate closely with senior developers, designers, product owners, and other team members to deliver high‑quality software solutions that follow best practices and meet customer needs. You will also support defect resolution, participate in code reviews, and continually grow your skills under the guidance and mentorship of a Senior C#/.NET Developer. What you'll do:

• Design, develop, test, and maintain application features using C#, ASP.NET, Entity Framework, and SQL Server
• Modify and enhance existing application code to improve performance, functionality, and maintainability
• Integrate third‑party components and APIs as needed
• Participate in the full software development lifecycle, including planning, requirements analysis, implementation, testing, and deployment
• Collaborate with senior developers and architects to implement technical designs and follow established patterns and standards
• Write clean, scalable, and maintainable code aligned with best practices and team guidelines
• Conduct unit and integration testing to validate functionality and ensure code quality
• Troubleshoot and resolve technical issues, defects, and performance bottlenecks
• Use Git/GitLab for source control, branching, and code collaboration
• Support O&M tasks such as minor enhancements, bug fixes, and performance tuning
• Participate in code reviews and apply feedback from senior engineers to improve your technical proficiency
• Assist with remediating code and package vulnerabilities identified through scans, with senior guidance What you’ll need:
• Bachelor’s degree
• 3–5 years of professional experience developing software using C# and the .NET framework
• Experience with ASP.NET, Entity Framework, and SQL Server
• Familiarity with architectural patterns and API styles (REST, RPC)
• Experience writing and executing unit tests and performing integration testing
• Understanding of secure coding practices and willingness to follow vulnerability remediation guidance
• Ability to collaborate with cross‑functional teams and translate requirements into technical tasks
• Strong problem‑solving skills and ability to work independently when implementing assigned tasks Bonus points if you have:
• Experience with cloud platforms (AWS or Azure)
• Basic understanding of DevOps practices or exposure to CI/CD pipelines (GitLab preferred)
• Experience working with Object‑Relational Mappers (ORMs) such as Entity Framework
• Knowledge of SQL or NoSQL database design principles
• Experience with containerization tools (Docker)
• Familiarity with Agile/Scrum development processes
• Relevant certifications in .NET development or cloud technologies.
• Experience working in an Agile/Scrum development environment.
• Strong problem-solving skills and attention to detail.
• Excellent communication and collaboration skills. Education/Experience Requirement
• 4 Year Degree Information Technology or related field or Equivalent Experience
• 8+ years Experience