Senior Backend / Systems Engineer (C/C++ & Custom Kernel)

Chikara HR; Paris; Sur place; EUR 85 000 - 100 000; Plein temps

Avantages offerts par ce poste

Meaningful equity

Budget for training

Flexible working arrangements

Résumé du poste

NEXUS is hiring in Paris to build a confidential AI platform with a custom Linux kernel at its core. This on-site role targets senior systems engineers who enjoy low-level work on memory, PCIe, and GPU integration.

You will own end-to-end kernel components at an early stage, with publishable work and meaningful BSPCE equity. You will operate in a fast-paced, English-speaking team, with the requirement to speak French for client interactions.

Qualifications

• Expert in C/C++ with memory management and systems focus.
• Strong understanding of Linux internals, DMA, PCIe and hardware behavior.
• Proven ability to optimize systems and demonstrate profiling results.

Responsabilités

• Build and maintain a stripped-down custom Linux kernel bridging CPU-encrypted memory with GPU compute.
• Make the GPU read encrypted memory safely and keep I/O air-gapped.
• Provision and tune NVIDIA GPUs, including PCIe passthrough and time-slicing.
• Wring latency out of a tightly constrained system, one context switch at a time.
• Contribute to open source where possible.

Connaissances

Low-level C/C++

Linux internals

Profiling

Senior ownership

CUDA/GPU programming

PCIe/DMA hardware

Outils

Linux kernel build tools

GPU provisioning tools

Description du poste

• Build the low-level systems and custom Linux kernel at the heart of a confidential AI platform, as one of the first hires
• Our client, NEXUS: a Paris deep-tech startup making sensitive data usable without exposing it. Backed by NVIDIA Inception, Scaleway and Station F
• Paris, mostly on-site
• €85,000 to €100,000 plus BSPCE (share options)

Most backend jobs live safely above the hardware. This one lives in it. NEXUS is building a confidential AI platform that lets companies use their most sensitive data without exposing it, and the whole thing rests on a custom Linux kernel that bridges encrypted memory and GPU compute. That kernel is yours to build.

This is for someone who thinks in memory registers, PCIe lanes and clock cycles, and enjoys it. If you have spent your career shaving microseconds off systems that had no business going faster, in trading, kernels or drivers, this is the same craft aimed at a problem that matters. And you can put your name to the work: it stays NEXUS's, but you are free to publish it and present it.

What you'll be doing

• Build and maintain a stripped-down custom Linux kernel that bridges CPU-encrypted memory with GPU compute
• Make the GPU read encrypted memory safely, and keep the I/O strictly air-gapped
• Provision and tune NVIDIA GPUs, down to PCIe passthrough and time-slicing
• Wring latency out of a tightly constrained system, one context switch at a time
• Contribute to open source where the work allows

What you'll bring

• You write low-level C and C++ every day: manual memory management, pointers, the systems layer
• You understand Linux internals, DMA, PCIe and how the hardware actually behaves
• You have made systems faster and can show the profiling to prove it
• You are senior enough to own a hard systems component end to end at an early-stage company
• CUDA and GPU programming are a bonus, not a must. A strong systems engineer can pick them up here
• This is a purely low-level systems role. Full-stack and web backgrounds are not the fit

The role is on-site in Paris, with some flexibility around life. You will need the right to work in France. The team works in English, with French language a requirement to speak with clients.

This is a team that debates its decisions. Expect to be asked why, and expect to ask it back. If being challenged on your thinking energises you rather than wears you down, you will fit in well.

Why you'll want it

• A kernel of your own, built from scratch
• Meaningful equity as one of the very first hires
• The rare freedom to publish your work and present it, in a field that usually hides it
• The room to grow into leading your own systems team
• A budget for training, and flexible working once you are settled
• Performance engineering on a problem few companies are even attempting

About our client, NEXUS

NEXUS is a Paris deep-tech company solving one of the hardest problems in AI: how to use sensitive data without exposing it. Using federated learning, NEXUS generates high-fidelity, GDPR-safe synthetic data, so organisations in finance, healthcare and other regulated fields can build AI without putting real data at risk. Its first product, MIRAGE, applies the same thinking to cybersecurity.

Backed by NVIDIA Inception, Scaleway, Station F, France Deeptech, Telecom Paris and Bpifrance, NEXUS is at an early stage and building its founding technical team now.

Diversity and Inclusion

At Chikara HR, we are committed to a diverse and inclusive recruitment process where every candidate is considered fairly. We welcome applicants from all backgrounds and will judge each candidate on their merits and what they can contribute.

We value people regardless of race, ethnicity, gender, sexual orientation, age, religion, disability or any other aspect of their identity. We are looking for talented, driven individuals, and if you believe you are a fit, we want to hear from you.

Data Processing

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