Full Stack .NET Developer

Harmonia Holdings Group, LLC • Washington, DC

1d • Onsite

About The Position

Harmonia is seeking a Full Stack .NET Developer to design, build, and maintain secure, scalable applications in a classified environment. This role is suited for a developer who is comfortable working across the stack from back-end services and database design to front-end interfaces. This person needs to be able to operate effectively in a structured, security-conscious environment. The developer will be expected to write production-quality code, troubleshoot complex issues across system layers, and contribute to ongoing modernization efforts.

Requirements

• Active Top Secret clearance with SCI eligibility (required).
• U.S. Citizenship required.
• 5+ years of professional experience in .NET/C# development
• Security+ certification.
• Strong experience building full stack applications using .NET frameworks (.NET Core, MVC, or similar)
• Proficiency with SQL Server, including T-SQL, stored procedures, and database design
• Experience troubleshooting and debugging across multiple system layers.
• Familiarity with secure development practices in regulated or classified environments.
• Experience working in Agile development teams.

Nice To Haves

• Experience with Azure DevOps, TFS, or similar CI/CD and build tools
• Familiarity with cloud platforms such as Azure or AWS
• Experience with version control systems (Git, TFS)
• Knowledge of SharePoint integration or development
• Exposure to secure mobile development or device management environments
• Strong problem-solving and performance tuning capabilities
• Ability to work effectively in a client-facing or mission-driven environment

Responsibilities

• Design, develop, test, and maintain full stack applications using C# and the .NET ecosystem
• Build and enhance back-end services, APIs, and data access layers
• Develop and maintain front-end components using modern web technologies (JavaScript, HTML, CSS)
• Design and optimize SQL Server databases, including stored procedures, functions, and performance tuning
• Troubleshoot and resolve issues across application, database, and infrastructure layers
• Identify and remediate security vulnerabilities in accordance with federal standards
• Support CI/CD pipelines and automated deployment processes
• Participate in Agile development processes, including sprint planning, demos, and retrospectives
• Contribute to secure mobile application support and integration efforts

Benefits

• Traditional and HSA- eligible medical insurance plans
• 100% employer-paid dental and vision insurance options
• 100% employer-sponsored STD, LTD, and life insurance
• 5% 401(k) company matching
• Flexible-schedules and teleworking options
• Paid holidays and PTO Accrual Plans
• Paid Parental Leave
• Professional development and career growth opportunities
• Team and company-wide events, recognition, and appreciation-- and so much more!

What This Job Offers

• Job Type: Full-time
• Career Level: Mid Level
• Education Level: No Education Listed
• Number of Employees: 101-250 employees