Top Senior .NET Developer Jobs in Philadelphia, PA

Own and evolve Swyfft’s partner-facing insurance API, including resource design, versioning, backward compatibility, authentication, rate limiting, error handling, metrics, documentation, and contract testing. Build production C# code, maintain the translation layer between public APIs and internal systems, support partner integrations, and collaborate with QA and product. The role requires substantial public API experience, strong API security and multi-tenancy knowledge, and fluency in C#, ASP.NET Core, SQL Server, and Azure.

Design and develop software systems based on business requirements, troubleshoot and resolve reported issues, and conduct peer code reviews. The role requires strong .NET, C#, ASP.NET MVC, Web API, Angular, dependency injection, testing, database, and software design experience. Candidates should understand SOLID principles, design patterns, Entity Framework, SQL Server, source control, and continuous integration. WCF, SOA, SSRS, and Kendo UI experience are advantageous. The position requires six or more years of .NET development experience and local, face-to-face availability in KOP, Pennsylvania.

Designs, develops, maintains, and troubleshoots scalable software applications using .NET, SQL Server, UI frameworks, and cloud technologies. Collaborates with product owners, developers, testers, and technology leads; participates in code reviews; writes documented code; and improves software development practices.

Build and support complex features across C#/.NET back-end services and React front ends. Responsibilities include technical design, API and data modeling, secure and tested coding, production troubleshooting, code reviews, mentoring, documentation, and improving engineering practices. Collaborate with Product, QA, DevOps, Technical Leads, and architecture teams while balancing delivery, maintainability, performance, accessibility, observability, and security.

Build and maintain full-stack behavioral health technology features and services. Responsibilities include translating team goals into technical plans, designing APIs and services, evaluating technical tradeoffs, identifying risks, contributing to architecture, collaborating with product and QA, mentoring junior engineers, and improving testing and engineering practices. The role requires C#, TypeScript, .NET, modern frontend frameworks, databases, CI/CD, Docker, Kubernetes, and automated testing experience.

Leads architecture and development of complex backend services for a commercial health plan platform. Designs .NET Core and Azure systems, develops claims, eligibility, and benefits functionality, manages healthcare data integrations, and owns cloud infrastructure and CI/CD architecture. Provides technical leadership through code reviews, testing standards, mentoring, and architecture decisions while ensuring performance, reliability, security, and regulatory compliance.

Develop and optimize Microsoft .NET applications, legacy systems, and microservices with a focus on performance, scalability, reliability, and observability. Responsibilities include code reviews, performance testing, CI/CD integration, architecture and sprint delivery, legacy code and SQL tuning, cloud application deployment on Azure, automated testing, and resolving customer issues. The developer collaborates with architects, QA, technical support, and cross-functional teams using SAFe Agile practices.

Senior .NET Software Engineer responsible for end-to-end software development using Microsoft technologies. Requires extensive experience in SDLC, design principles, technical documentation, web application development with .NET, Agile/SCRUM, Entity Framework, database design, and version control. Familiarity with project tools JIRA, TEMPO, Bitbucket, and Confluence preferred.

Senior .NET Web App Developer responsible for designing and building .NET web applications, implementing Oracle PL/SQL solutions, using Entity Framework and Blazor, applying design principles, producing technical documentation, performing performance tuning, and collaborating in Scrum/Agile teams with Bitbucket, JIRA, Tempo, and Confluence.

Develop and maintain web-based applications using .NET/C#, JavaScript, HTML/CSS, SQL and Oracle/SQL Server. Perform root cause analysis, collaborate with teams for requirements, follow Agile SDLC, present change demonstrations, and use Azure DevOps/Jira for lifecycle management. Implement and maintain Blazor components.

Develop and support corporate tax workstation products using .NET, C#, Dynamics 365, Power Automate, ASP.NET, and SQL Server. Responsibilities include technical design, coding, testing, troubleshooting, deployment, performance and security improvements, documentation, code reviews, and mentoring developers. The role collaborates with stakeholders and international teams to deliver reliable solutions on schedule.

Design, build, and maintain production-grade .NET web applications and APIs on Azure. Own full-stack delivery from data models and SQL to front-end components, CI/CD, testing, and architecture. Collaborate with product and delivery teams, participate in code reviews, and ensure secure, observable, well-tested services.

Leads the design, development, and implementation of full-stack applications using C#, .NET, Angular, Azure, and SQL Server. Collaborates with cross-functional teams, ensures application security, performance, and scalability, applies Git-based version control practices, mentors developers, and stays current with emerging technologies.

Build and maintain scalable, cloud-native APIs and high-value core system components using .NET and related technologies. Lead software architecture and testing discussions, enhance core offerings, collaborate cross-functionally, and ensure quality through code reviews, unit testing, functional testing, telemetry, and performance tuning. Mentor teammates and contribute to continuous technical and process improvement.

Lead development of secure, scalable digital banking software across front-end and backend systems. Design Angular or React applications, build APIs, optimize SQL performance, integrate third-party platforms, improve code quality, implement testing strategies, and mentor engineers. Collaborate with cross-functional teams in an Agile environment while supporting cloud-native practices, regulatory compliance, and continuous product improvement.

Owns the design, development, testing, deployment, and maintenance of production software. Builds C#/.NET backend services, Angular web applications, and .NET MAUI mobile apps; optimizes SQL Server databases; resolves production issues; improves reliability, security, performance, and observability; writes tests and documentation; participates in code reviews; and translates ambiguous business needs into maintainable technical solutions.

Build scalable backend-heavy services and applications using C# and .NET, while contributing to Angular and TypeScript UI development. Design and develop REST APIs and microservices, work with relational databases, implement automated testing and CI/CD, and ensure system security, scalability, and performance. Preferred work includes event-driven architectures, messaging systems, NoSQL databases, caching, search technologies, and mentoring engineers or leading technical initiatives.

Seeking a Senior .NET Developer with experience in Sitecore CMS and financial systems integration. Must have strong software development skills and experience with Agile methodologies.

The .Net Developer will work in agile teams, handling software development tasks including design, testing, and deployment while supporting existing applications.

The .NET FullStack Developer will design, code, test, and debug software product enhancements while ensuring high performance and maintainability, working closely with various teams.

Lead design, implementation, and maintenance of the CoverGo SaaS platform across front-end and back-end. Provide technical direction, optimize performance and security, enforce coding standards, conduct code reviews, mentor junior developers, and collaborate with product and design teams to build scalable, high-traffic insurance enterprise solutions.

The role involves converting visual designs into web pages, collaborating with teams, and ensuring compliance with best practices for front-end development.

Lead analysis, design, development, testing, implementation and support of global financial .NET applications. Translate user requirements into technical specs, oversee onshore/offshore teams, participate in code reviews, maintain documentation, estimate work, follow SDLC, and support code promotion (TFS).

The Senior .NET Software Engineer will drive development of .NET software products, focusing on back-end engineering, code reviews, and collaborating with cross-functional teams.

Lead design and delivery of scalable, reliable software using C#/.NET, SQL Server, React, and Azure. Own complex initiatives from design through operations, mentor engineers, improve CI/CD, observability, and apply DDD/TDD/VSA practices. Use modern APIs, microservices or modular monoliths, and AI-assisted tooling to improve delivery.