Java Backend Engineer Jobs in San Francisco, CA

About Nscale

Nscale is the GPU cloud engineered for AI. We provide cost-effective, high-performance infrastructure for AI start-ups and large enterprise customers. Nscale enables AI-focused companies to achieve superior results by reducing the complexity of AI development. Our GPU cloud bolsters technical capabilities and directly supports strategic business outcomes, including cost management, rapid innovation, and environmental responsibility.

We thrive on a culture of relentless innovation, ownership, and accountability, where every team member takes pride in their work and drives it with excellence and urgency. As an Nscaler, you'll build trust through openness and transparency, where everyone is inspired to do their best work. If you join our team, you'll be contributing to building the technology that powers the future.

About The Role

The Network Operations and Engineering teams at Nscale operate some of the most demanding networking environments in the industry, supporting tightly coupled GPU clusters where network performance directly impacts customer outcomes.

We're looking for a Principal Network Engineer – AI Infrastructure to provide technical leadership across Nscale's high-speed networking domain.

This role is focused on owning the reliability, scalability, and long-term evolution of our Infiniband and RDMA-based network fabrics. You will operate as a technical authority, influencing architecture, standards, and operational practices across teams while tackling the most complex network challenges in the platform.

What You'll Be Doing

Owning the technical direction and operational strategy for Nscale's AI interconnect networks

Designing, reviewing, and evolving large-scale Infiniband and RoCE fabric architectures to support future growth and workload demands

Acting as the senior escalation point for the most complex network incidents, guiding deep technical investigations and systemic fixes

Driving cross-team initiatives to improve fabric reliability, performance predictability, and operational maturity

Defining standards for hardware configuration, congestion control, routing, firmware lifecycle management, and change safety

Partnering with SRE, Compute Platform, and Network Architecture teams to influence end-to-end system design

Mentoring senior and mid-level network engineers, raising the bar for operational rigor and technical excellence

• Driving measurable improvements in uptime, latency consistency, capacity efficiency, and incident reduction

About You (Skills / Qualifications)

10+ years of experience in network engineering, with deep focus on HPC, AI, or hyperscale data centre networking

Expert-level operational and architectural experience with Infiniband and/or large-scale RoCE fabrics

Deep understanding of RDMA internals, congestion management, and fabric-level failure modes

Strong expertise in modern data centre routing and control planes (BGP, OSPF, ECMP)

Proven ability to debug and resolve cross-layer issues spanning hardware, firmware, kernel, and application communication libraries

Demonstrated ability to lead complex technical initiatives across teams without direct authority

• A systems-level mindset, balancing performance, reliability, scalability, and operational cost

Nice to Have

Extensive experience with NVIDIA/Mellanox networking platforms in production AI or HPC environments

Deep familiarity with distributed training frameworks and GPU communication patterns

Experience designing network observability systems for high-cardinality, high-throughput environments

• Prior experience influencing platform or infrastructure strategy at scale

What We Can Offer You

At Nscale, you'll find a collaborative, supportive, and innovative environment where your contributions spark real impact. We're building something extraordinary, and we want you at the core.

• Highly competitive package (base + equity) with reviews every 12 months.
• Join the fastest-growing tech startup, your chance to push boundaries, collaborate with brilliant minds, and make your mark on cutting-edge AI.
• Expect a dynamic progression plan tailored to your ambitions. Grow by trying new things, leading, challenging the status quo, and owning your impact, always with our full support.

Equal Opportunities Statement

We strongly encourage applications from people of colour, the LGBTQ+ community, people with disabilities, neurodivergent people, parents, carers, and people from lower socio-economic backgrounds.

If there's anything we can do to accommodate your specific situation, please let us know.

The responsibilities outlined in this job description are not exhaustive and are intended to provide a general overview of the position. The employee may be required to perform additional duties, tasks, and responsibilities as assigned by management, consistent with the skills and qualifications required for the role.