(Senior) Network Engineer UK in London

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

We’re hiring a Network Engineer to design, deploy, and operate the networking services that underpin both Nscale’s internal management platform and customer‑facing cloud infrastructure. This role sits within our Engineering team and is part of the Network Engineering Team, which is responsible for internet transit, WAN connectivity, and data centre networking. You’ll work closely with deployment teams to ensure bills of materials are correct and fit for purpose, and provide input into data centre layouts and rack elevations so reference architectures are implemented correctly.

This is a high‑impact role at the core of our AI infrastructure platform. You’ll help ensure the performance, reliability, and scalability of the high‑speed Ethernet and InfiniBand networks that support Nscale’s infrastructure, while also serving as an escalation point for complex networking issues across the organisation.

What you’ll be doing:

• High-Speed Network Design and Operations
  • Design high‑speed Ethernet‑based networks that support internal and customer‑facing infrastructure.
  • Operate production network services to maintain stability and performance.
  • Design high‑speed InfiniBand networks for AI and HPC‑oriented environments.
  • Deploy and operate InfiniBand networking infrastructure in production.
• Infrastructure Deployment and Architecture
  • Partner with deployment teams to ensure BOMs are correct and fit for purpose.
  • Guide rack elevation planning to ensure reference architectures are deployed correctly.
  • Support the implementation of networking standards across new infrastructure rollouts.
• Performance, Troubleshooting, and Escalation
  • Troubleshoot performance issues across both Ethernet and InfiniBand networks.
  • Investigate complex network problems affecting core infrastructure services.
  • Act as an escalation point for advanced networking issues within the support organisation.
• Automation and WAN Connectivity
  • Automate the deployment and initial stand‑up of hardware from multiple vendors.
  • Automate day‑to‑day operational tasks across multi‑vendor network hardware.
  • Design WAN infrastructure to support connectivity across the platform.
  • Implement and support WAN networking services as part of the wider infrastructure estate.

KPIs:

• Ethernet network deployment and operational reliability
• InfiniBand network performance and troubleshooting effectiveness
• Accuracy and fitness of networking BOMs and reference architecture implementation
• Automation of hardware deployment and day‑to‑day network operations

About You:

• Proven experience designing, deploying, and operating high‑speed Ethernet networks.
• Strong knowledge of VLAN, LACP, MLAG, BGP, OSPF, EVPN, and VXLAN.
• Proven experience designing, deploying, and operating InfiniBand networking.
• Hands‑on expertise with InfiniBand configuration, performance tuning, and troubleshooting, including Subnet Managers, QoS, and RDMA.
• Strong knowledge of WAN technologies including MPLS, BGP, IPSec, GRE, and SD‑WAN.
• Knowledge of HPC networking topologies, including Fat Tree and Rail.
• Strong scripting capability in Python or Bash.
• Strong knowledge of optics and network hardware to support BOM design.

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 compensation package (base + bonus + equity), with performance reviews every 12 months. Join one of the fastest‑growing AI infrastructure companies — your chance to directly shape how global AI capacity is planned and deployed.

Expect a dynamic progression plan tailored to your ambitions. Grow by leading critical cross‑functional initiatives and shaping capital strategy — always with our full support. Human‑First Flexibility: We treat you as humans first. Our flexible workplace trusts Nscalers to deliver, giving you the autonomy to shape your day around life's moments.

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.