Top .NET Developer Jobs in Philadelphia, PA

Design, build, and operate .NET backend services and APIs using C#/ASP.NET Core and EF Core/SQL. Author and iterate specification artifacts (OpenSpec), leverage AI coding assistants, implement automated tests, ship via CI/CD to the cloud, review peers' specs/code, mentor engineers, and collaborate with product, QA, and cross-functional teams to deliver production services.

Full‑stack .NET developer responsible for writing, maintaining and optimizing code, designing APIs and system architecture, implementing unit/integration tests, supporting deployments, troubleshooting performance issues, and collaborating with QA and stakeholders. May work variable hours including nights/weekends.

Lead and mentor an engineering team building GovIntel and GovChannel product capabilities. Own technical direction, design and deliver scalable SaaS features, APIs, integrations, and platform reliability. Partner with Product, QA, Cloud Ops, and stakeholders to prioritize work, drive CI/CD and observability practices, lead reviews and incident response, and apply AI-assisted tools to improve development speed and quality.

Develop, test, and support .NET applications, APIs, and data solutions within the SDLC. Collaborate on design, code reviews, data modeling, and source control. Troubleshoot issues, support data movement initiatives, and adhere to risk, regulatory, and internal control standards while contributing to modernization efforts.

Develop, test, integrate, and maintain .NET/C# web applications supporting NAVSUP logistics. Design system interfaces and databases, implement secure REST APIs, perform unit/integration testing, manage source control, troubleshoot issues, and collaborate with stakeholders in an Agile environment.

Develop and maintain enhancements for the M5 FleetFocus web application using C#, ASPX/ASP.NET, HTML5, XML, and JavaScript. Build and modify SQL statements and database objects in Oracle and SQL Server. Define C# interfaces for 3rd-party integrations, troubleshoot tickets, collaborate with PM/QA/support, and use Visual Studio 2013 and SVN for code changes.

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.

Design, develop, implement and support web applications using .NET Core. Collaborate with internal bank teams and external vendors, troubleshoot production issues, and apply strong interpersonal, leadership, and problem-solving skills.

Design, develop, and maintain scalable ASP.NET/C# APIs and microservices and front-end interfaces (Vue.js, AngularJS) for retail omni-channel and POS platforms. Contribute to architecture, write production-quality code, troubleshoot issues, participate in code reviews, and collaborate with product, design, and QA to deliver features with minimal onboarding.

Designs, codes, tests, and documents .NET applications; follows SDLC and Agile/Scrum practices; supports Tier 3 incidents; works on system integration and CI/CD (Jenkins, GitHub); collaborates with product owners and vendors; participates in production releases and mentors junior developers.

Seeking a Senior Full Stack .NET Developer to work on a social good project, with strong skills in C#, AngularJS, design, and UX. Requires 5+ years of experience.

The Staff Engineer will leverage 5+ years of experience in C#, JavaScript, and frameworks to lead and innovate solutions in a collaborative environment.

Own production reliability for customer-facing radar and weather data services across Azure, colocation, and edge Kubernetes. Refactor C#/.NET services for multi-replica safety, design multi-cluster HA, operate self-managed Kubernetes, improve observability and automation, lead incident response and postmortems, and drive operational excellence and capacity planning.

As a Principal .NET Software Engineer at Versapay, you will modernize payments infrastructure, improve scalability, design distributed services, and take ownership of payment workflows while collaborating with various teams to enhance customer experience.

The .NET Developer will engage in software development primarily using C#, ASP.NET, and SQL Server. Responsibilities include developing large applications and ensuring effective communication.

Senior .NET full-stack developer responsible for custom application development, API integrations, database optimization, deployments, troubleshooting, performance, security, and production support using .NET/C#, ASP.NET Core, SQL, modern frontend frameworks, cloud, and CI/CD.

The .NET Developer will design, develop, and enhance web-based applications, maintain ERP solutions, and collaborate with cross-functional teams to support software throughout its lifecycle.

Maintain and enhance a portfolio of .NET web applications: write C#/.NET Core code, unit tests, and documentation; develop SQL queries and stored procedures; perform debugging, defect resolution, and ATO vulnerability remediation; ensure accessibility (Section 508/WCAG) compliance; use Azure DevOps for source control and CI/CD; participate in code reviews and technical working sessions under senior developer guidance.

Provide technical leadership to design, modernize, and sustain a portfolio of .NET web applications and Azure infrastructure. Develop and migrate WebForms to ASP.NET Core and SSRS to Power BI, maintain SQL Server databases, enforce secure coding and ATO compliance, ensure accessibility (Section 508/WCAG), and mentor junior developers while coordinating with VA stakeholders.

Hands-on lead developer/technical architect responsible for coding (.NET Core/.NET 8+), designing Azure-first architectures, building microservices and APIs, implementing Azure PaaS services and monitoring, performing code reviews and mentoring, troubleshooting production issues, and coordinating delivery with onshore/offshore teams.

Contract remote .NET/Kentico web developer to build interactive, dynamic websites. Requires front-end web development experience and familiarity with the Kentico CMS. Six-week engagement.

Design, build, and maintain scalable web applications for payroll and accounting. Collaborate with engineers and product partners, write tested code, participate in code reviews, contribute to architecture, improve CI/CD and monitoring, support production (including on-call), and communicate progress while continuously learning.

Design, develop, test, and deploy .NET solutions (APIs and web apps). Build and consume RESTful services, work with SQL and NoSQL databases, use cloud (Azure/AWS) and Docker, apply unit/integration/performance testing, participate in code reviews, define features via spikes, and architect scalable, high-performance systems. Support occasional after-hours and on-call rotation.

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.