Senior .Net Application Developer - Phildelphia, Pennsylvania

About FIDx

FIDx is a groundbreaking, fast-paced, industry-changing, growing company out of Berwyn, Pennsylvania. We provide a platform that allows financial advisors to fully integrate annuities into the advisory ecosystem which will ultimately better serve their clients. FIDx is modernizing annuity distribution. We do this by providing a top technology and service platform that connects legacy tools, experience, and expertise of high-quality insurance companies to the delivery platform and the process of the advisory marketplace.

To learn more, please visit our website at (Use the "Apply for this Job" box below)..

We are seeking an experienced .NET Senior Developer with a strong focus on backend and full-stack development to help design, build, and maintain modern, scalable applications. The ideal candidate will have deep expertise in .NET technologies, SQL Server, and cloud-based solutions on Azure, along with experience contributing to overall system architecture and performance. This role involves close collaboration with front-end, product, and Dev Ops teams and serves as a technical leader and mentor for junior developers.

The Senior Developer will also contribute to development standards, best practices, and long-term platform evolution across the organization.

• Design & Architecture
• Design, architect, and evolve backend and full-stack applications with a focus on scalability, performance, security, and maintainability
• Define and enforce backend and full-stack architectural standards, patterns, and best practices
• Collaborate with front-end teams to design clean, efficient APIs (REST/JSON) and integration patterns
• Design and optimize data models, database schemas, and data access strategies using SQL Server
• Evaluate and recommend new backend, cloud, and platform technologies, frameworks, and tools
• Participate in system design discussions to ensure technical feasibility and long-term sustainability
• Development & Maintenance
• Build, enhance, and maintain backend services and APIs using .NET (e.g., C#, ASP.NET Core)
• Develop and maintain full-stack features where needed, collaborating closely with front-end developers
• Implement robust business logic, and integrations with internal and external systems
• Write clean, well-tested, and well-documented code
• Troubleshoot and resolve application issues, performance bottlenecks, and production defects
• Participate in code reviews to ensure quality, consistency, and adherence to standards
• Integration & Collaboration
• Work closely with front-end engineers, product managers, and stakeholders to deliver high-quality features
• Collaborate with Dev Ops teams to support CI/CD pipelines, deployments, and cloud infrastructure on Azure
• Serve as a technical escalation point for complex backend or system-wide issues
• Communicate technical concepts clearly to both technical and non-technical stakeholders
• Quality, Testing & Optimization
• Implement and maintain front-end testing strategies, including unit, integration, and end-to-end testing
• Ensure applications meet performance, security, and accessibility standards
• Continuously improve application performance, usability, and reliability
• Mentorship & Leadership
• Provide guidance and mentorship to junior and mid-level developers
• Contribute to team knowledge-sharing, documentation, and continuous improvement initiatives

• Provide backup and support for others in the group as necessary

• Strong experience with .NET technologies (C#, ASP.NET Core, Web APIs)
• Experience with Angular a plus
• Solid understanding of backend and full-stack architecture, design patterns, and best practices
• Strong experience with SQL Server, including schema design, query optimization, and performance tuning
• Experience building and consuming RESTful APIs
• Experience working with Microsoft Azure services (e.g., App Services, Azure SQL, Storage, Dev Ops, or similar)
• Familiarity with Agile/Scrum development methodologies
• Experience with version control systems (Git) and collaborative development workflows
• Knowledge of testing frameworks and tools for backend and application-level testing
• Strong problem-solving and debugging skills
• Excelle…