Senior Windows Systems Developer

Kyber; Paris; Hybrid; EUR 70,000 - 100,000; Full time

Benefits offered by this job

Health Insurance

Transportation card

Job summary

Kyber, based in Paris with open remote options, seeks a seasoned Windows systems programmer to design and optimize low-level components, services, and drivers. You will work with native Windows APIs, drive performance improvements, and help shape architecture through rigorous code reviews.

The role requires deep knowledge of Windows internals, powerful debugging skills, and a track record of handling complex, security‑critical software with autonomy and precision.

Qualifications

• Extensive experience with Windows architectures and kernel/user-mode boundaries.
• Proficient in C/C++/Rust and low-level debugging.
• Strong with Windows debugging tools and crash analysis.
• Experience with security, performance and memory management.
• Ability to work autonomously on complex systems.

Responsibilities

• Designing, developing, and optimizing low-level Windows system components for Kyber
• Developing Windows services, system agents, and drivers (user-mode and kernel-mode, depending on context)
• Working directly with native Windows APIs (Win32, NT Native API) and interacting with Windows ecosystem (Active Directory/Kerberos, etc.)
• Investigating and resolving complex issues related to performance, memory management, synchronization, and security
• Performing advanced debugging (crash dump analysis, kernel debugging, stack analysis, occasional reverse engineering)
• Writing clear and durable technical documentation
• Participating in low-level architecture decisions and critical code reviews
• Conducting continuous technical watch on Windows internals and system-level tooling.

Skills

Windows internals

Kernel/user-mode

Debugging tools

C/C++/Rust

Code reviews

Tools

Visual Studio

Windows toolchains

Git

Job description

Salary aligned with the market + typical French benefits (Health Insurance, 50% Transportation card)

About Kyber

Kyber is an open-source SDK and platform to control remote machines, from Remote Desktop to Robots Teleoperation/Teleobservation. Kyber is a multi-stream and multi-actuator transport in extremely-low latency, over the quic protocol.

Clients use Kyber to control robots, drones, desktop, servers in the cloud or just remote rendering of interactive 3D programs. Kyber is done for Remote RealTime, where every millisecond matters.

Kyber is developed by engineers from the VLC and FFmpeg community, and we code in Rust, in C and in assembly. We have some development in Go too.

We're a quite technical team, but cool to work with.

We are based in Paris area and open to Remote Work in Europe. Full time only.

Role

The successful candidate will be responsible for:

• Designing, developing, and optimizing low-level Windows system components for Kyber
• Developing Windows services, system agents, and drivers (user-mode and kernel-mode, depending on context)
• Working directly with native Windows APIs (Win32, NT Native API) and interacting with Windows ecosystem (Active Directory/Kerberos, etc.)
• Investigating and resolving complex issues related to performance, memory management, synchronization, and security
• Performing advanced debugging (crash dump analysis, kernel debugging, stack analysis, occasional reverse engineering)
• Writing clear and durable technical documentation
• Participating in low-level architecture decisions and critical code reviews
• Conducting continuous technical watch on Windows internals and system-level tooling.

Required Technical Skills

• Excellent knowledge of Windows internal architecture and ecosystems
• Strong understanding of synchronization mechanisms, memory management, and system-level error handling + Clear understanding of user-mode vs kernel-mode boundaries, as well a user session management
• Hands-on experience with Windows debugging and analysis tools
• Programming Languages : C / C++ / Rust / X86/x64
• Tools & Environment : Visual Studio and Windows toolchains, Gitl and collaborative development workflows

You

• 5 to 10 years of professional experience in software development, with a significant focus on Windows systems programming
• Proven track record working on technically complex and critical systems
• Strong low-level reasoning and ability to understand large, existing codebases
• High level of rigor, autonomy, and attention to detail, Strong interest in solving non-trivial technical problems
• Ability to share expertise and mentor junior engineers

Nice-to-Have Skills :

• Experience in system security or Windows component hardening, Background in reverse engineering or malware analysis, Contributions to low-level or systems-oriented open-source projects
• Experience in constrained environments (real-time systems, high availability, security-critical software)

Interview Process

• 15-Min Screening Call : Quick chat about motivation, fit and answer your non tech questions.
• 2x1-Hour Technical/Product Interview : Deeper dive into your problem-solving approach with our CTO and/or our lead solution architect
• Team Meet & Greet : Informal session to ensure good culture fit.

What We Offer

• Highly technical and intellectually challenging projects
• An environment that values genuine engineering expertise and that is tech focused (no nonsense meetings or reportings)
• Strong autonomy in technical decision-making