Fuse Energy UK

Vertically integrated energy: generation, trading, retail

HPC Network Engineer

Network Engineering & AdministrationConfirmed live in the last 24 hours

Full-timeLondon, UK

About the Job

Requirements

At least 5 years of experience as a network engineer operating production data centre networks.
Strong dynamic routing experience, particularly BGP, plus overlay and encapsulation design and troubleshooting such as EVPN/VXLAN.
Hands-on experience designing and operating leaf-spine or Clos fabrics.
Experience with modern data centre network operating systems and the Linux networking stack, beyond vendor command-line interfaces.
Practical RDMA fabric experience with lossless Ethernet, such as RoCEv2 with PFC/ECN/DCQCN tuning, or InfiniBand, and understanding the importance of lossless behaviour for GPU workloads.
Working practice in network automation, including scripting such as Python, configuration management such as Ansible, generating configuration from a source of truth, and version-controlling changes.
Solid Linux administration fundamentals, including debugging from both the host and switch sides.
Experience with network telemetry and monitoring such as Prometheus/Grafana, sFlow/IPFIX, or streaming telemetry.
Experience operating corporate or campus networks, including wired and wireless infrastructure, switching, NAC/802.1X, VPN, and remote access.
Clear communication skills and interest in teaching.

Responsibilities

Design and operate lossless, RDMA-capable fabrics, such as RoCEv2 or InfiniBand, for GPU compute and storage traffic, including QoS, congestion control, and buffer tuning at scale.
Build and manage leaf-spine data centre fabrics with routed underlay and overlay designs such as BGP and EVPN/VXLAN.
Implement and maintain per-tenant network isolation across compute, storage, and management planes.
Automate network provisioning, configuration, and validation, treating switch configuration as code using tools such as Ansible, Python, and NetBox as the source of truth, deployed through continuous integration.
Build fabric telemetry and observability, including flow-level and buffer-level visibility, dashboards, and alerting to detect congestion and link degradation before tenants are affected.
Troubleshoot performance issues end to end, from optics and cabling through switch buffers to NIC/DPU configuration and host collective-communication behaviour.
Operate the out-of-band management network, console access, and remote recovery paths.
Support tenant onboarding through segmentation and addressing, bandwidth and isolation guarantees, and capacity planning as the cluster scales.
Write clear design documentation that captures decisions, rationale, and rejected alternatives.
Own and maintain the office network, including wired and wireless infrastructure, firewalling, VPN/remote access, and office-to-data-centre connectivity.
Upskill colleagues on networking through documentation, run-throughs, and pairing.

Desired Qualifications

GPU cluster networking, including NVIDIA Spectrum-X or Quantum InfiniBand, ConnectX/BlueField NICs and DPUs, UFM, SHARP, or equivalent.
Container networking, including CNI and BGP integration.
Experience with collective-communication libraries.
Multi-tenant VRF-based isolation.
Enterprise firewalls such as FortiGate or Palo Alto.
Storage networking such as NVMe-oF.
Bare-metal provisioning such as MAAS, PXE, or Redfish.
Optical-layer experience at 200/400/800G.
Greenfield data centre network build experience.
CCNP, CCIE, or equivalent certification.

HPC Network Engineer

Fuse Energy · London, United Kingdom · Full-time · Posted 2026-11-03

Workplace: on_site

Description

Fuse is an AI-first energy company on a mission to make energy abundant and affordable, fast. We combine first-principles thinking with cutting-edge technology to build a radically better energy system.

We've raised over $200M from top-tier investors including Balderton, Lakestar, Accel, Creandum, Lowercarbon, Ribbit, 20VC, Hummingbird and Collaborative Fund, alongside strategic angels including Nico Rosberg and GPs behind Meta, Revolut, Spotify and Uber.

We're building a fully integrated energy company: developing our own solar, batteries and other generation projects, building our own hardware, improving and developing grid infrastructure, trading power in real time, and installing distributed energy in homes. By selling directly to consumers, we cut out the middleman, lower costs and pass the savings on to our customers.

You'll design, deploy and operate the network fabric for our multi-tenant AI cluster: the high-performance compute and storage fabrics carrying RDMA traffic between GPUs, the tenant-facing and management networks, firewalling and tenant isolation, and the out-of-band infrastructure that keeps it all recoverable. Beyond the data centre, you'll own the office network and act as the networking authority for the company. You own the fabric from architecture through day-2 operations.

Responsibilities

Design and operate lossless, RDMA-capable fabrics (e.g. RoCEv2, InfiniBand) for GPU compute and storage traffic, including QoS, congestion control and buffer tuning at scale
Build and manage leaf-spine data centre fabrics, with routed underlay and overlay design (e.g. BGP, EVPN/VXLAN)
Implement and maintain per-tenant network isolation across compute, storage and management planes
Automate network provisioning, configuration and validation, treating switch config as code (e.g. Ansible, Python, NetBox as source of truth), deployed through CI
Build telemetry and observability for the fabric: flow-level and buffer-level visibility, dashboards and alerting that catch congestion and link degradation before tenants do
Troubleshoot performance issues end to end, from optics and cabling through switch buffers to NIC/DPU configuration and collective-communication behaviour on the hosts
Operate the out-of-band management network, console access and remote recovery paths
Support tenant onboarding: segmentation and addressing, bandwidth and isolation guarantees, and capacity planning as the cluster scales
Write clear design documentation capturing decisions, rationale and rejected alternatives
Own and maintain the office network: wired and wireless infrastructure, firewalling, VPN/remote access and office-to-data-centre connectivity
Upskill colleagues on networking through documentation, run-throughs and pairing

Requirements

5+ years as a network engineer operating production data centre networks
Strong dynamic routing experience (BGP in particular), plus overlay/encapsulation design and troubleshooting (e.g. EVPN/VXLAN)
Hands-on experience with leaf-spine / Clos fabric design and operation
Experience with modern data centre network operating systems and comfortable in the Linux networking stack, not just a vendor CLI
Practical RDMA fabric experience: lossless Ethernet (e.g. RoCEv2 with PFC/ECN/DCQCN tuning) or InfiniBand, understanding why lossless behaviour matters for GPU workloads
Network automation as a working practice: scripting (e.g. Python), configuration management (e.g. Ansible), config generation from a source of truth, version-controlled changes
Solid Linux administration fundamentals: you can debug from the host side as well as the switch side
Experience with network telemetry and monitoring (e.g. Prometheus/Grafana, sFlow/IPFIX, streaming telemetry)
Experience running corporate/campus networks: wired and wireless, switching, NAC/802.1X, VPN and remote access
Clear communicator who enjoys teaching
Bonus: GPU cluster networking (NVIDIA Spectrum-X or Quantum InfiniBand, ConnectX/BlueField NICs and DPUs, UFM, SHARP or equivalent); container networking (CNI, BGP integration); collective-communication libraries; multi-tenant VRF-based isolation; enterprise firewalls (FortiGate, Palo Alto); storage networking (NVMe-oF); bare-metal provisioning (MAAS, PXE, Redfish); optical layer at 200/400/800G; greenfield data centre network build; CCNP/CCIE or equivalent

Benefits

Competitive salary and eligibility for equity
Biannual bonus scheme
Fully expensed tech to match your needs
Private health insurance
Breakfast and dinner allowance for office-based employees

As we hire globally, benefits vary by location.

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About the Company

Fuse Energy UK

Vertically integrated energy: generation, trading, retail

Fuse Energy UK is a London-based energy company that handles renewable generation, trading, and retail supply for households and businesses in a single chain. It owns and operates solar and wind farms, trades electricity to balance supply and price, and sells energy directly to customers, reinvesting profits into new renewable projects. Its edge comes from being vertically integrated across generation, trading, and retail, with strong backing from investors and a leadership team formerly at Revolut. Its goal is to grow its UK customer base and expand into Ireland, Spain, and the US while scaling up renewable capacity.

Company size: 201-500
Company stage: Series B
Total funding: $200M
Headquarters: London, United Kingdom
Founded: 2022

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