Lead Software Systems Engineer - GPU Performance

About Nebius: Nebius is leading a new era in cloud infrastructure for the global AI economy. We are building a full-stack AI cloud platform that supports developers and enterprises from data and model training through to production deployment, without the cost and complexity of building large in-house AI/ML infrastructure. Built by engineers, for engineers. From large-scale GPU orchestration to inference optimization, we own the hard problems across compute, storage, networking and applied AI. Listed on Nasdaq (NBIS) and headquartered in Amsterdam, we have a global footprint with R&D hubs across Europe, the UK, North America and Israel. Our team of 1,500+ includes hundreds of engineers with deep expertise across hardware, software and AI R&D. We are looking for a Lead Software Systems Engineer - GPU Performance to play a key role in building our hyperscaler platform, working across its core components while analyzing and optimizing the performance of large-scale GPU clusters at the intersection of hardware and software. You will operate across the full stack—from hardware and system software to networking (InfiniBand/RoCE), virtualization (KVM/QEMU), and distributed communication layers (e.g., MPI, NCCL). In this role you will • Focus on understanding system behavior across multiple layers, identifying performance bottlenecks, and driving improvements that shape how our clusters are built, operated, tuned, and validated. • Investigate and troubleshoot performance issues of GPU cluster under real workloads (training and inference) • Evaluate and integrate new hardware, system configurations and tuning approaches through software stack • Support complex performance-related escalations from internal teams and customers • Work closely with infrastructure, software engineering and hardware vendor teams (e.g. NVIDIA, Mellanox, Intel) • Contribute to hardware and cluster qualification (acceptance), ensuring systems meet performance expectations We expect you to have: • 5+ years of professional experience in system-level software development (focused on performance optimization, low-level programming).
 • 3+ years of hands-on experience with Linux systems (administration, troubleshooting, and performance tuning).
 • In-depth understanding of server architecture, including PCIe devices, NICs, Linux OS/Kernel, and high-performance computing (HPC) systems.
 • Strong proficiency in one or more performance-oriented programming languages (C/C++, Go, Python). We conduct coding interviews as part of the process. Key employee benefits: • Health insurance: 100% company-paid medical, dental and vision coverage for employees and families. • 401(k) plan: Up to 4% company match with immediate vesting. • Parental leave : 20 weeks paid for primary caregivers, 12 weeks for secondary caregivers. • Remote work reimbursement: Up to $85/month for mobile and internet. • Disability & life insurance: Company-paid short-term, long-term and life insurance coverage. #LI-LH2 Pay Transparency We offer competitive compensation and benefits packages. Actual compensation will be determined based on job-related factors, including experience, skills, qualifications, the level at which the candidate is hired, and geographic location, consistent with applicable law. Base Compensation Range $170,000 — $300,000 USD Benefits & Perks: • Competitive compensation • Career growth and learning opportunities • Flexibility and ownership • Collaborative and innovative culture • Opportunity to work on impactful AI projects • International environment and talented teams What's it like to work at Nebius: Fast moving - Bold thinking - Constant growth - Meaningful impact - Trust and real ownership - Opportunity to shape the future of AI Equal Opportuni