Senior Backend Engineer — .NET / C#

Our core platform services are built on .NET 8 running on Windows Server and Linux containers. We need a senior backend engineer who understands the CLR garbage collector well enough to explain why gen2 collections are spiking, and who can build a gRPC service that handles 50,000 RPS without breaking a sweat.

Responsibilities

• — Design and implement backend services in C# / .NET 8 — REST APIs, gRPC endpoints, and background workers
• — Build and maintain Entity Framework Core data access layer with SQL Server — query optimization, migration management, split queries for performance
• — Integrate with legacy COM+ and MSMQ services during our modernization migration
• — Implement authentication and authorization using Windows Authentication, OAuth 2.0, and OpenID Connect
• — Write comprehensive unit and integration tests using xUnit, NSubstitute, and Testcontainers
• — Participate in code review, architecture discussions, and quarterly platform planning
• — On-call rotation (1 week per 8 weeks) — production incident response with structured postmortems

Requirements

• — 7+ years of .NET/C# development experience in enterprise environments
• — Deep knowledge of ASP.NET Core, dependency injection, middleware pipeline, configuration system
• — Strong SQL Server skills — query optimization, execution plans, indexing strategy
• — Experience with gRPC, message queues (RabbitMQ, Azure Service Bus), and distributed system patterns
• — Understanding of Windows authentication (Kerberos, NTLM, claims) and modern OAuth/OIDC
• — Comfortable with performance profiling: dotTrace, PerfView, ETW, WinDbg/SOS
• — Excellent written communication — RFCs, ADRs, technical specification documents

Nice to Have

• — Experience migrating .NET Framework 4.8 to .NET 8
• — Familiarity with TPL Dataflow or Channels for high-throughput pipelines
• — Experience with Windows Services, IIS advanced configuration, and AppLocker
• — Knowledge of cryptographic APIs in .NET (X509Certificate2, CNG, DPAPI)

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