Sr. Full Stack Software Developer

Holtec International • Winslow Township, NJ

3d • $120,000 - $150,000 • Onsite

About The Position

The Senior Software Developer plays a critical role in the design, development, and maintenance of enterprise applications, supporting both new development and legacy systems. This role serves as a technical subject matter expert, partnering with internal stakeholders to define solutions, guide architectural decisions, and deliver scalable, secure software in a complex, fast‑paced environment. The ideal candidate brings strong full‑stack expertise, sound technical judgment, and the ability to independently drive high‑quality solutions from concept through delivery.

Requirements

• Bachelor’s degree in Computer Science, Engineering, or a related field, with 10+ years of professional software development experience in enterprise environments
• Deep expertise in C#, .NET Core, and .NET Framework, with experience developing, maintaining, and modernizing both modern and legacy codebases across full‑stack applications
• Strong full‑stack development and architecture experience, including RESTful APIs, front‑end technologies (Blazor, HTML5, CSS3, JavaScript, Bootstrap), and scalable system design utilizing SOLID principles, design patterns, dependency injection, and CQRS
• Advanced SQL Server expertise, including schema design, index strategy, stored procedures, query optimization, and execution plan analysis
• Experience with enterprise authentication and authorization (OAuth2, OIDC, Azure AD / Entra ID or similar), along with secure development practices
• Proven ability to lead and own architectural decisions at both application and database levels, while working effectively across complex, multi‑application enterprise environments
• Strong experience improving and navigating legacy codebases, with a focus on enhancing performance, scalability, and maintainability
• Experience with Git-based version control, collaborative code review, DevOps practices (CI/CD pipelines), and containerization technologies (Docker)
• Familiarity with performance profiling and troubleshooting tools, application modernization/migration (.NET Framework to .NET Core), and emerging development practices including AI-assisted coding tools
• Strong communication and stakeholder management skills, with the ability to translate business requirements into technical solutions, work independently, manage priorities, and deliver high-quality outcomes
• High attention to detail with a strong focus on code quality, documentation, and user experience, including UI/UX considerations

Responsibilities

• Serve as the technical subject matter expert across a portfolio of enterprise applications
• Partner with internal stakeholders to gather requirements, define scope, and identify risks early
• Translate complex business processes into sound technical designs and deliver solutions independently
• Design and document application architecture and database structures
• Enforce coding standards, architectural patterns, and development best practices
• Architect scalable, maintainable solutions and evaluate existing systems for optimization
• Perform peer code reviews and uphold high standards of code quality
• Apply and promote secure software development practices
• Identify technical risks and provide clear, actionable solutions
• Develop well‑structured, efficient, and maintainable code
• Estimate and scope work independently in planning sessions
• Maintain and enhance system and code documentation
• Mentor and support junior developers where applicable

Benefits

• Industry‑leading medical, dental, and vision coverage with a generous employer premium contribution and Day 1 eligibility!
• FLEX Program – Hybrid work opportunities available for eligible roles, where business needs and role requirements allow
• 401(k) retirement plan with up to a 5% company match and immediate vesting to support long‑term financial security
• Paid time off and 11 paid holidays to support rest, balance, and recharge
• Wellness program offering rewards for participation in company‑supported health initiatives
• Commuter benefits supporting mass transit and commuter parking options
• Company‑paid life and AD&D insurance for added peace of mind
• Education assistance to support continued education and professional growth
• Employee support and voluntary benefits, including an Employee Assistance Program and optional coverage such as disability, legal, identity theft, and insurance programs

What This Job Offers

• Job Type: Full-time
• Career Level: Senior