Windows Service Developer

COMPANY OVERVIEW ThreatLocker® is a leader in endpoint protection technologies, providing enterprise-level cybersecurity tools to improve the security of servers and endpoints. The ThreatLocker® platform with Application Allowlisting, Ringfencing™, Storage Control, Elevation Control, Endpoint Network Control, Configuration Management, and Operational Alert solutions are leading the cybersecurity market toward a more secure approach of blocking the exploits of application vulnerabilities. JOB OVERVIEW ThreatLocker is seeking a highly skilled and self-driven Windows Service Developer to join our cybersecurity engineering team. In this role, you will design, implement, and optimize high-performance background services in C#/.NET, with a strong focus on Windows OS internals. These services are critical components of ThreatLocker’s endpoint protection platform — defending systems from the inside out. The ideal candidate is an expert developer with a deep understanding of Windows architecture, secure coding practices, and performance optimization. You will work closely with system internals, file systems, and network layers to build resilient, scalable, and secure service components. We value developers who think like attackers, engineers with precision, and debug like forensic analysts. The role will be based in Orlando, FL and is an in-office position. KEY RESPONSIBILITIES • Design, develop, and maintain robust Windows Services using C#/.NET, with a focus on security, performance, and reliability. • Work with low-level Windows components, including Windows APIs, file system hooks, and network stack integration. • Implement advanced cybersecurity features, such as privilege control, intrusion prevention, and data protection mechanisms. • Diagnose and resolve complex issues involving system performance, concurrency, memory management, and network communication. • Collaborate across teams to ensure services align with enterprise security and compliance standards. • Participate in code reviews, share best practices, and contribute to a clean, maintainable codebase. • Continuously improve service resilience, monitoring, and observability with a proactive mindset. REQUIRED QUALIFICATIONS • Expert-level proficiency in C#/.NET Framework and .NET Core, including asynchronous programming and multithreading. • Strong understanding of Windows internals: services, registry, process lifecycle, and kernel-level concepts. • Solid grasp of network protocols (TCP/IP, HTTP/S, DNS) and experience with network control or firewall-level filtering. • Hands-on experience with debugging and profiling tools (e.g., WinDbg, Process Monitor). • Familiarity with SQL Server, including stored procedures and index optimization. • Experience designing and consuming RESTful APIs. • Strong understanding of secure coding practices and software design patterns. • Bachelor’s degree in Computer Science, Software Engineering, or equivalent hands-on experience. PREFERRED QUALIFICATIONS IN • Experience with C/C++ interop, kernel development, or Windows filter drivers. • Proven ability to design highly concurrent, long-running Windows Services with efficient resource management. • Familiarity with endpoint protection, EDR, or network monitoring technologies. • Understanding of containerized environments and DevOps pipelines for service deployment. • Hands-on experience with GitHub Actions, CI/CD pipelines, and multi-target build orchestration (.NET Framework and .NET Core). • Deep understanding of Windows security architecture, access control, and threat mitigation strategies. • Microsoft or cybersecurity certifications are a strong plus. WORKING CONDITIONS The duties described below are representative of those encountered while performing the essential functions of this position. If necessary, reasonable accommodation may be requested and will be evaluated for its relationship to the essential functions that must be performed. • Job will generally be performed in an office environment but may require travel to visit company offices and/or property locations. • While performing duties of this job, would occasionally require to stand, walk, sit, reach with hands and arms, climb or balance, stoop or kneel, talk and hear, and use fingers and hands to feel objects and tools. • Must occasionally lift and/or move up to 25 pounds. • Specific vision abilities required include close vision, distance vision, depth perceptions, and the ability to adjust focus. A background check and drug/substance screening are required after a conditional offer. Employment will proceed only upon receiving clear results from both. ThreatLocker also conducts randomized drug and substance testing approximately every 60 days, in line with the same screening standards.