We are seeking an experienced Senior .NET Full Stack Developer for a 12-month contract role based in Livingston, New Jersey. You will join a development team focused on modernizing business-critical applications within a financial services environment. The position emphasizes backend development with a 75/25 split between backend and frontend work, and requires strong analytical and problem-solving skills to understand the business context behind the applications you develop. Responsibilities Design, develop, enhance, and modernize enterprise applications using .NET Core, SQL, and React (Angular experience also considered). Allocate approximately 75% of development time to backend systems and 25% to frontend application development. Participate in modernization efforts involving existing applications, services, and business processes. Analyze business requirements and translate them into effective, maintainable technical solutions. Develop a strong understanding of the business processes and rules supported by the applications. Evaluate multiple potential approaches to development challenges and select solutions based on scalability, maintainability, performance, and business impact. Write efficient SQL queries and work extensively with relational databases and data-driven applications. Develop and enhance user-facing functionality using React. Review existing code and application architecture to identify opportunities for modernization and improvement. Troubleshoot complex application and data issues by identifying root causes rather than simply addressing symptoms. Collaborate closely with developers, QA resources, product stakeholders, and business partners. Participate in code reviews and technical discussions, clearly explaining development decisions and potential tradeoffs. Leverage modern development tools, including AI-assisted development, while maintaining ownership and understanding of the resulting code. Qualifications Required Strong professional development experience with .NET Core and C#. In-depth SQL skills and experience working with relational databases, with demonstrated expertise in performance tuning and joins. Experience developing modern web applications with React or Angular. Strong backend application development experience, including business logic and data-intensive applications. Demonstrated ability to analyze complex requirements and understand the business purpose behind application functionality. Strong troubleshooting and root-cause analysis skills. Ability to articulate why a particular technical approach was selected, what alternatives were considered, and the potential consequences of taking a different approach. Experience working with existing or legacy applications and participating in application modernization initiatives. Strong understanding of software development principles, application architecture, and maintainable coding practices. Strong verbal and written communication skills with the ability to participate effectively in detailed technical discussions. Preferred Experience within financial services, retirement services, benefits, payroll, investment, or other transaction-oriented environments. Experience modernizing legacy enterprise applications into newer .NET and web-based architectures. Experience working on systems involving complex business rules, calculations, financial transactions, or large datasets. Familiarity with AI-assisted software development tools and practices.