Windows Service Developer

ThreatLocker; Orlando (FL); On-site; USD 90,000 - 120,000; Full time

Job summary

ThreatLocker is seeking a skilled Windows Service Developer for their Orlando, FL office. The role involves designing and optimizing high-performance background services in C#/.NET, focusing on Windows OS internals and security.

The ideal candidate will possess expert-level programming skills, especially in C#/.NET, and a solid understanding of Windows architecture and secure coding practices. This position plays a crucial role in enhancing ThreatLocker's endpoint protection solutions.

Qualifications

• Expert-level proficiency in C#/.NET Framework and .NET Core.
• Strong understanding of Windows internals including registry and process lifecycle.
• Hands-on experience with debugging tools and network control.

Responsibilities

• Design, develop, and maintain Windows Services with a focus on security and performance.
• Work with Windows APIs and file system integration.
• Collaborate across teams to ensure security standards are met.

Skills

C#/.NET programming

Windows internals knowledge

Network protocols understanding

Debugging and profiling (WinDbg)

SQL Server experience

Education

Bachelor’s degree in Computer Science or equivalent experience

Tools

WinDbg

Process Monitor

Job description

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 such as WinDbg and 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

• 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.