Senior Staff Software Engineer

Software Engineer 4 – C# .NET with CLR Profiling About the Role : We are looking for a Senior Staff Software Engineer to work on our Seeke r Inlin e Agen t fo r .NE T — a dynamic application security testing (DAST) agent that instruments .NET applications at runtime to detect security vulnerabilities. You will work across C#, C++, and multiple .NET runtime versions to build and maintain profiler-based instrumentation, security checkers, and platform integrations . Responsibilities Design, develop, and maintain the .NET agent core, including security checkers (SQLi, XSS, CSRF, deserialization, etc.) and taint analysis engine Develop and optimize native C++ profilers using the CLR Profiling API for both .NET Framework and .NET Core/.NET 5+ Support multi-platform builds targeting Windows (x64), Linux (x64, ARM64), and Alpine/musl environments Extend agent capabilities to new .NET versions (.NET 8, 9, 10+) and hosting models (AWS Lambda, Azure Functions, gRPC, OWIN, WC F)Collaborate on CI/CD pipelines (GitLab CI) across multiple OS targets and Docker-based build environments Write and maintain unit tests (NUnit) and integration tests across framework versions Troubleshoot low-level runtime issues involving IL rewriting, method interception, and memory management Participate in code reviews, architecture discussions, and contribute to build system improvements (Cake Build, CMake, MS Buil d) Required Skill s 9+ ye ars of professional software development experie nce Str o ng C# proficie ncy acro ss .NET Framework (3.5–4.8 .1) a nd .NET Core/.NET 5+ (up to .NET 10) C ++ experie nce — working with native interop, COM, and platform APIs (CLR Profiling API is a strong plus) Deep understanding of t he . N ET CLR intern als — assembly loading, JIT compilation, IL metadata, type system Experience wi th multi-platf o rm developm ent (Windows & Linux) Proficiency wi th CMa k e, MS Bu ild, and complex build orchestration Strong debugging skills — ability to diagnose issues across managed/native boundaries Experience wi th Git a nd CI/CD pipeli nes (GitLab CI preferr ed) Preferred Sk ills Experience in applica t ion secu rity, DAST/IAST, or security instrumentation Knowledge of O W ASP To p 10 vulnerabilities and detection techniques Experience w ith Do cker containerization and multi-arch builds (x64, ARM64, Alpine) Familiarity w ith server l ess platf orms (AWS Lambda, Azure Functions) Experience w ith WiX insta ller authoring and NuGet packaging Knowledge of c ode obfusca tion techniques Familiarity with logging frameworks (log4net, spdlog, NLog) Experience w ith WebSo cket communication proto cols Nice t o Have Experience contributing to profilers, APM agents, or runtime instrumentation tools Background in reverse engineering or binary analysis Familiarity with ReSharper code inspection tooling