Senior.NET Developer

Role Description We are looking for a senior C#/.NET engineer who modernizes the platform, not just maintains it. Our flagship product, Volunteer Impact, is a mature, revenue-generating platform built on VB.NET and .NET Framework. It needs to move to .NET 10 and C# to enable further development. Lead the migration of the Volunteer Impact backend from VB.NET/.NET Framework to C#/.NET 10, defining the migration approach and executing it incrementally against a live production system. Modernize a custom security framework (70+ custom attributes) into something that works on the new stack, with zero authorization bypasses. Strengthen the existing CI/CD pipeline and, with our quality engineering function, wire in the gates that catch functional and performance regressions before they reach production. Ship migrated areas to production independently and incrementally while the legacy application keeps running. Become the second engineer who can independently cut, validate, and deploy a production release. Identify, evaluate, and replace legacy dependencies that don’t have a path forward to modern .NET, without introducing functional or performance regressions. Make the technical sequencing calls: which areas migrate first, which dependencies get replaced when, and where automated conversion is viable vs. manual rewrite. Lay the foundation for the team to grow by modernizing the stack to one that any C# developer can contribute to. Qualifications 8+ years of professional C#/.NET experience, with real depth in the framework, not just the latest version. Experience leading or being the technical anchor on a .NET Framework-to-.NET Core (or later) migration of a large, production monolith serving paying customers. Ability to articulate the approach for migrating a production system incrementally with minimal downtime. Deep NHibernate experience is strongly preferred. Experience replacing legacy dependencies in production: DI containers, bundling frameworks, service hosting, and unsupported third-party libraries. Hands-on experience with legacy .NET ecosystem components: ASP.NET MVC-to-Core routing, custom security frameworks, and dependencies without a clean upgrade path. Familiarity with migrating SSRS reports to a modern reporting platform is a benefit. Experience improving CI/CD pipelines for .NET applications and working with quality functions to build gates that catch functional and performance regressions early. Comfortable in a small core team with shared DevOps and DBA support available, and a dedicated quality engineering partner. VB.NET familiarity is a bonus, not a requirement. Requirements Strong technical decision-making skills. Ability to debug hands-on and know when to pull in the right support. Benefits Medical, dental