Software Developer (.NET / ASP.NET Full Stack)

About the role

3 Squared Technology Group is seeking a motivated Junior to Mid-Level Software Developer with experience in .NET, ASP.NET, and full-stack application development. You'll support the development, enhancement, integration, testing, and maintenance of mission-critical applications and information systems supporting government customers.

The ideal candidate has a solid foundation in software development and is comfortable across both front-end and back-end technologies. This position suits a developer who can work independently on assigned tasks while collaborating with senior developers, system administrators, cybersecurity personnel, database administrators, and government stakeholders.

Candidates must possess an active Secret security clearance and a current CompTIA Security+ certification at the time of hire.

Key responsibilities

• Design, develop, test, troubleshoot, and maintain applications using C#, .NET, .NET Core, and ASP.NET technologies.
• Develop and maintain web applications using ASP.NET MVC, Web API, Razor, HTML, CSS, JavaScript, and related technologies.
• Develop and maintain backend application logic, APIs, services, and database integrations.
• Support full-stack development across presentation, business logic, and data layers.
• Create, modify, and optimize SQL queries, stored procedures, and database interactions in Microsoft SQL Server.
• Troubleshoot application defects and perform root-cause analysis.
• Support modernization and enhancement of existing and legacy applications.
• Participate in testing, debugging, code reviews, configuration management, and deployment.
• Develop and maintain technical documentation for applications, software changes, interfaces, and configurations.
• Work within established Agile/Scrum and/or DevSecOps development processes.
• Use source-control and development tools such as Git, Azure DevOps, and Visual Studio.
• Collaborate with cybersecurity personnel to meet DoD security requirements and secure-coding practices.
• Assist with vulnerability remediation, STIG findings, and security-related software updates.
• Participate in requirements discussions with technical and functional stakeholders, and support production applications.

Mandatory qualifications

Candidates must meet all of the following requirements:

• Active DoD Secret security clearance.
• Current CompTIA Security+ certification.
• U.S. citizenship.
• Bachelor's degree in Computer Science, Software Engineering, Information Technology, Information Systems, or a related technical discipline; equivalent relevant experience may be considered if permitted by contract requirements.
• Approximately 1–5 years of professional software development experience.
• Experience developing applications using C# and .NET / .NET Core.
• Experience with ASP.NET, ASP.NET MVC, and/or ASP.NET Web API.
• Working knowledge of front-end technologies such as HTML, CSS, JavaScript, Bootstrap, or similar frameworks.
• Experience with Microsoft SQL Server or a comparable relational database.
• Understanding of object-oriented programming principles and software development best practices.
• Familiarity with RESTful APIs and application integration.
• Experience using source-control tools such as Git.
• Strong troubleshooting, analytical, and problem-solving skills, and the ability to communicate with technical and non-technical team members.

Preferred qualifications

• Experience supporting Department of Defense, U.S. Air Force, or other federal government systems.
• Experience modernizing or maintaining legacy .NET applications.
• Experience with Azure DevOps, CI/CD pipelines, DevSecOps, or automated deployment.
• Experience with JavaScript frameworks such as Angular or React.
• Experience developing or integrating REST APIs and web services.
• Familiarity with application security, vulnerability remediation, and secure-coding standards.
• Experience in Agile/Scrum development environments.
• Familiarity with DoD RMF, STIGs, and cybersecurity requirements.

Desired technical skills

• Primary — C#, .NET, .NET Core, ASP.NET, ASP.NET MVC, Web API, SQL Server
• Front end — HTML, CSS, JavaScript, Bootstrap, Razor, Angular / React
• Development & DevOps — Visual Studio, Git, Azure DevOps, CI/CD, Agile / Scrum
• Security — CompTIA Security+, DoD cybersecurity, RMF, STIG, secure coding, vulnerability remediation

Candidate profile

The successful candidate will be a technically capable developer eager to grow into increased responsibility while supporting applications in a structured DoD environment.

Junior candidates should demonstrate strong technical fundamentals and the ability to learn quickly. Mid-level candidates should be able to independently develop, troubleshoot, and deliver software components while assisting less-experienced team members as needed.

Clearance & certification are mandatory

An active Secret security clearance and a current CompTIA Security+ certification are mandatory for this position. Candidates who do not currently meet both requirements will not be considered.