Senior Full Stack .NET Developer

Senior Full Stack .NET Developer

Nakupuna Companies is seeking a highly experienced Senior Full Stack.NET Developer to design, develop, and modernize enterprise applications using the Microsoft technology stack. This is a hands-on development role requiring deep expertise in modern.NET technologies and front-end frameworks.

Responsibilities

The following reflects management's definition of essential functions for this job but does not restrict the tasks that may be assigned. Management may assign additional duties and responsibilities to this job at any time due to reasonable accommodation or other reasons.

• Design, develop, and maintain enterprise applications using C#, ASP.NET,.NET Framework 4.x, and.NET 6/7/8/9/10+
• Build and maintain RESTful APIs and backend services using.NET Web API
• Develop modern responsive user interfaces using React
• Integrate front-end applications with backend APIs and services
• Design and implement scalable database solutions using Microsoft SQL Server
• Participate in modernization efforts migrating legacy applications to modern.NET platforms

Requirements Analysis & Solution Design

• Work directly with stakeholders, product owners, and analysts to understand functional and technical requirements
• Translate business requirements into technical designs and implementation approaches
• Produce technical documentation, architecture diagrams, and data flow representations
• Provide level-of-effort estimates and development strategies
• Participate in Agile planning, backlog grooming, and sprint activities

Software Quality & Automated Testing

• Develop unit tests to validate business logic and application components
• Implement automated testing using frameworks such as xUnit, NUnit, or MSTest
• Write integration tests for APIs and service interactions
• Develop front-end test coverage using tools such as Jest or React Testing Library
• Ensure applications are designed with testability and maintainability in mind
• Participate in code reviews and enforce engineering quality standards
• Support application security testing efforts, including SAST and DAST scan remediation
• Maintain appropriate test coverage for critical application functionality

Code Quality & Engineering Standards

• Follow modern software engineering practices including clean architecture and design patterns
• Conduct peer code reviews and approve pull requests
• Ensure applications meet security, accessibility (Section 508), and performance standards
• Troubleshoot and resolve complex technical issues
• Recommend improvements to application architecture and system performance

Technical Leadership

• Provide guidance and mentorship to other developers
• Promote best practices in secure coding, testing, and maintainable software design
• Assist with modernization and refactoring of legacy applications
• Serve as a senior technical contributor within the development team

Qualifications

The ideal candidate will have strong experience building scalable applications, designing APIs, and working directly with stakeholders to translate business requirements into well-engineered software solutions. This role requires a developer who can think architecturally while remaining hands-on with coding, testing, and implementation. Experience with mobile application development or integration, including iOS, Android, or cross-platform frameworks (e.g., React Native, .NET MAUI) is strongly preferred.

Required Education and Experience:

• Bachelor's degree in Computer Science, Information Technology, or related field
• 8–12+ years of experience in software development

Preferred Qualifications:

• Experience modernizing legacy applications to .NET 8+
• Experience building scalable microservices or service-based architectures
• Experience with Azure-hosted application services
• Experience integrating with enterprise systems or messaging platforms
• Experience performing application security code reviews

Clearance:

• You must obtain and maintain an active Public Trust/Confidential security clearance for continued employment
• Must be a U.S. citizen

Physical Requirements:

• Ability to perform repetitive motions with the hands, wrists, and fingers
• Ability to engage in and follow audible communications in emergency situations
• Ability to sit for prolonged periods at a desk and working on a computer