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 Seeker Inline Agent for .NET — 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

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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 Build)

Required Skills

• 9+ years of professional software development experience
• Strong C# proficiency across .NET Framework (3.5–4.8.1) and .NET Core/.NET 5+ (up to .NET 10)
• C++ experience — working with native interop, COM, and platform APIs (CLR Profiling API is a strong plus)
• Deep understanding of the .NET CLR internals — assembly loading, JIT compilation, IL metadata, type system
• Experience with multi-platform development (Windows & Linux)
• Proficiency with CMake, MS Build, and complex build orchestration
• Strong debugging skills — ability to diagnose issues across managed/native boundaries
• Experience with Git and CI/CD pipelines (GitLab CI preferred)

Preferred Skills

• Experience in application security, DAST/IAST, or security instrumentation
• Knowledge of OWASP Top 10 vulnerabilities and detection techniques
• Experience with Docker containerization and multi-arch builds (x64, ARM64, Alpine)
• Familiarity with serverless platforms (AWS Lambda, Azure Functions)
• Experience with WiX installer authoring and NuGet packaging
• Knowledge of code obfuscation techniques
• Familiarity with logging frameworks (log4net, spdlog, NLog)
• Experience with WebSocket communication protocols

Nice to Have

• Experience contributing to profilers, APM agents, or runtime instrumentation tools
• Background in reverse engineering or binary analysis
• Familiarity with ReSharper code inspection tooling

Skills Required
Docker, Nunit, GRPC, Aws Lambda, Xss, Azure Functions, .Net Core