Sr. Principal C#​/.NET Engineer

Sr. Principal C#/.NET Engineer (Mission-Critical Systems)

We are seeking a seasoned Sr. Principal C#/.NET Engineer to lead the modernization and enhancement of a large-scale, mission-critical security integration platform. This is a high-impact technical role for a "heavy hitter" who thrives on solving deep architectural challenges and debugging complex, distributed systems. You will be responsible for accelerating the delivery of high-priority features while ensuring the platform remains highly reliable and fault-tolerant.

The ideal candidate can jump into a massive, existing codebase and become productive almost immediately.

• Design, implement, and optimize high-performance C# services and frameworks for a large-scale security ecosystem.
• Lead refactoring efforts and architectural improvements to modernize legacy components while maintaining system integrity.
• Troubleshoot and resolve deep-level bugs, memory bottlenecks, and reliability issues across multi-threaded and event-driven systems.
• Work extensively with message-based architectures, Windows services, and real-time communication protocols (Sockets, Networking).
• Author clear technical documentation for complex APIs, system interfaces, and deployment processes to ensure long-term maintainability.
• Serve as a technical authority within the engineering team, providing guidance and mentorship to mid-level and senior engineers.

• Education:
  
  Bachelor's or Master's in Computer Science or a related technical field.
• Experience:
  
  7–10 years of professional software engineering with a focus on backend systems.
• Technical Mastery
  • Expert-level C#:
    Deep knowledge of the .NET ecosystem (Framework and Core).
  • System Internals:
    Strong experience in multi-threaded programming and Windows system-level services.
  • Real-Time Communications:
    Proficiency in networking protocols, sockets, and message-based architectures.
  • AI Integration:
    Experience leveraging Copilot AI and various LLM models to accelerate development.
• Attributes:
  Proven ability to work independently in a contract environment with minimal ramp-up time and a "solution-first" mindset.

• Prior experience with Security Integration or Access Control platforms.
• Advanced diagnostic skills:
  Windows Memory Dump analysis, memory profiling, and performance tuning.
• Database expertise: SQL Server, , and Entity Framework.
• Modern Dev Ops fluency:
  Azure Dev Ops, Git Hub Actions, and CI/CD pipeline management.

Equal Opportunity Employer / Disabled / Protected Veterans