Principal Software Engineer

Radiant, United Kingdom

What you will do

What you'll do

As a Principal Software Engineer, you will help set the technical direction for a core part of Radiant's AI cloud, joining one of four teams: Infra & Cluster, Observability, MLOps Training, or MLOps Inference. We'll match you to the team that fits your experience.

You'll lead the design and delivery of the distributed systems that run GPU infrastructure and AI workloads at scale, partnering closely with product, infrastructure, SRE, networking, and storage teams, and with customers running the most demanding workloads.

What you need

Your profile

Extensive experience building and operating large-scale distributed systems, infrastructure software, or ML platforms.
A track record of technical leadership at staff or principal level, including setting direction across multiple teams and delivering complex, high-stakes systems.
Strong hands-on engineering skills in Go, Python, or similar.
Deep technical expertise in at least one of:
Infra & Cluster: provisioning (PXE, Redfish, IPMI, BMCs, firmware), cluster management, inventory, and lifecycle automation
Observability: metrics, logs, traces, OpenTelemetry, streaming pipelines, and high-cardinality time-series data
MLOps Training: Kubernetes and Slurm orchestration, PyTorch distributed, NCCL, checkpointing, and fault tolerance
MLOps Inference: model serving, batching, autoscaling, GPU utilisation, quantisation, and latency tuning
Strong foundations in Kubernetes, containers, Linux, high-performance networking, and GPU clusters.
Hands-on experience with technologies such as Redfish, Prometheus, OpenTelemetry, ClickHouse, Kafka, Slurm, vLLM, NVIDIA Triton, or similar.
Excellent written and verbal communication, including clear design documents and explaining complex trade-offs to technical and non-technical audiences.
Comfortable working directly with customers on highly technical problems.

What you bring

Domain expertise: Bring deep expertise in your team's area, and know where it breaks at scale.
Engineering excellence: Write and review code that sets the standard for correctness, performance, and maintainability.
Architectural judgement: Make sound long-term decisions on systems that are hard to change once built.
Technical leadership: Influence direction across teams without relying on authority, and grow the engineers around you.
Systems thinking: Understand how your area interacts with compute, networking, storage, and the rest of the cloud platform.
Ownership: Drive capabilities from design through production, operation, and continuous improvement.

Qualities we look for

Set the standard: Every single day, you spot opportunities to constructively shake things up
Inspire the change: There's no blueprint for the future. You'll embrace challenges and change
You're real and you're true to yourself: We cherish and celebrate diversity so you'll feel right at home whoever you are and whoever you're talking to, you treat everyone the same.

WHY SHOULD YOU JOIN US?

What sets us apart is our blend of modern technology, competitive benefits, and an open, welcoming work culture that enables our people to thrive.

Here are just some of the great things you can expect from us

25 days of annual leave
A culture that emphasises results over hierarchy, process & ego: we place great emphasis on the quality, ingenuity and creativity of work.
Open communication, regular feedback: we value smooth collaboration, direct and actionable feedback, and believe that leading with empathy and a growth mindset makes us better together.
Learning Time: we all have dedicated learning time to focus on new skills, projects or interests that lay outside of your day-to-day job.
Health & Wellbeing: we want everyone to feel healthy and happy, so we offer private medical insurance via Bupa.
Cycle to Work Scheme: we're committed to building a sustainable business, so we encourage cycling to work.
Gympass subscription to a variety of gyms and wellbeing apps
Participation in the company shares program
Enhanced parental pay & leave

Our process: Talent screen → Hiring Manager → Technical interview (two Principal Engineers) → Whiteboard Session → Final.

Principal Software Engineer

What you will do

What you'll do

Principal Software Engineer

What you will do

What you'll do

Key responsibilities

What you need

Your profile

What you bring

Qualities we look for

Here are just some of the great things you can expect from us

The teams

About Radiant

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Radiant