Senior Software Engineer - Platform Runtime

About us

PhysicsX is a deep-tech company with roots in numerical physics and Formula One, dedicated to accelerating hardware innovation at the speed of software. We are building an AI-driven simulation software stack for engineering and manufacturing across advanced industries. By enabling high-fidelity, multi-physics simulation through AI inference across the entire engineering lifecycle, PhysicsX unlocks new levels of optimization and automation in design, manufacturing, and operations — empowering engineers to push the boundaries of possibility. Our customers include leading innovators in Aerospace & Defense, Materials, Energy, Semiconductors, and Automotive.

Senior Software Engineer – Platform Runtime London (Hybrid) | Engineering | Full Time

The Role

PhysicsX is developing a platform used by Data Scientists and Simulation Engineers to build, train and deploy Deep Physics Models. As the platform scales to meet the demands of world class engineering teams, we are investing heavily in the runtime layer that underpins all workload scheduling, lifecycle management and compute orchestration.

We are looking for a Senior Software Engineer to join our Platform Runtime team. This role sits at the heart of how we extend Kubernetes to support the complex, long running and resource intensive workloads that PhysicsX customers depend on. You will own the design and delivery of Kubernetes Operators and runtime components that define how our platform provisions, manages and recovers workloads at scale.

This is a deeply technical, hands on engineering role. You will work closely with Platform SRE, Data Integration and product teams to define runtime contracts, surface observability and ensure the platform is reliable, extensible and operable in production.

• Design, build and operate production grade Kubernetes Operators that manage the full lifecycle of PhysicsX workloads, including provisioning, scaling, health management and graceful termination.
• Own the runtime architecture across multi cloud and on premises environments, ensuring consistent behaviour regardless of where compute runs.
• Drive the adoption and evolution of service mesh capabilities using Istio, including traffic management, mutual TLS and observability integration.
• Design and implement virtual cluster strategies using vCluster or equivalent tooling to support multi tenancy and workload isolation at the runtime layer.
• Collaborate with platform and infrastructure teams to define and maintain clear runtime interfaces and contracts.
• Establish and own reliability practices for runtime components, including SLOs, alerting and incident playbooks.
• Mentor engineers across the platform organisation and contribute to engineering standards, design reviews and technical direction.
• Evaluate and integrate upstream Kubernetes ecosystem tooling, contributing back where appropriate.

What You Bring to the Table

• Kubernetes Operator experience – you have designed, built and operated at least one production Kubernetes Operator. This is a firm requirement for the role.
• Golang expertise – 3 or more years of professional Golang development. You write idiomatic, testable and maintainable Go and are comfortable leading code reviews and establishing patterns.
• Deep Kubernetes knowledge – you understand the Kubernetes API machinery, reconciliation loops, controller runtime, admission webhooks and custom resource definitions inside out.
• Service mesh experience – hands on experience with Istio in a production environment, covering traffic shaping, observability, mTLS and policy enforcement.
• Multi tenancy and isolation – experience with vCluster, Capsule or equivalent tooling to provide workload and namespace isolation within shared Kubernetes clusters.
• Distributed systems background – a strong understanding of how to design and troubleshoot distributed systems at scale, including consensus, failure modes and recovery strategies.
• Multi cloud and on premises – experience operating Kubernetes across multiple cloud providers and on premises infrastructure, with an appreciation of the differences in networking, storage and permission management.
• Software engineering foundations – you are comfortable writing production code and are expected to do so regularly.
• Platform engineering mindset – you think in terms of internal products, developer experience and long term maintainability, not just delivery.
• AI infrastructure tools familiarity - You are familiar and/or have professional experience with software suites typically used to manage data and pipelines at scale, such as Kubeflow, Kedro, Kubetorch among others.

Ideally

• Experience contributing to open source Kubernetes projects or the wider CNCF ecosystem.
• Exposure to GPU workload scheduling or accelerated compute environments.
• Experience with Terraform and/or Crossplane for infrastructure provisioning.
• Background in simulation, ML platform engineering or HPC environments.
• Kubernetes certifications such as CKA, CKAD or CKS are a welcome signal of structured knowledge.

What we offer

Build what actually matters

Help shape an AI-native engineering company at a formative stage, tackling problems that genuinely matter for industry and society. This is work with real-world impact - and something you can be proud to stand behind.

Learn alongside exceptional people

Work with a high-caliber, collaborative team of engineers, scientists, and operators who care deeply about doing great work, and about helping each other get better. We come from diverse backgrounds, but we share a commitment to operating at the highest level and addressing some of the most complex challenges out there. If you’re ambitious, thoughtful, and driven by impact, you’ll feel at home.

Influence over hierarchy

We operate with a flat structure: good ideas win - wherever they come from. Questioning assumptions and challenging the status quo isn’t just welcomed, it’s expected.

Sustainable pace, long-term ambition

Building meaningful technology is a marathon, not a sprint. We believe in balancing focused, ambitious work with a life beyond it. Our hybrid model blends time together in our Shoreditch office with work-from-home days, giving you the flexibility to work sustainably while staying connected in person.

And it doesn’t stop there …

🚀Equity options - share meaningfully in the company you’re helping to build.

🏦10% employer pension contribution - because investing in future matters.

🍽️Free office lunches - to keep you energised and focused.

👶Enhanced parental leave - 3 months full pay paternity and 6 months full pay maternity leave, to provide extra flexibility during the moments that matter most.

🍼YellowNest nursery scheme - to help working parents manage childcare costs.

☀️ 25 days of Annual Leave (+ Public Holidays) - because taking time to rest matters.

🏥Private medical insurance - 100% employee cover, giving you complete peace of mind.

💪Wellhub Subscription - gain access to thousands of gyms, classes and wellness apps, supporting both physical and mental wellbeing.

👀Eye tests - because good work depends on good health.

📈Personal development - dedicated support for learning, development, and leveling up over time.

💛Employee Assistance Programme (EAP) - confidential wellbeing support, available whenever you need it.

🚲Bike2Work scheme and 🚆Season ticket loan - to make getting to work easier and greener.

🚗Octopus EV salary sacrifice - for a simpler, more sustainable way to drive electric.

🔎 Watch this space, we’re continuing to build this as we grow…

We value diversity and are committed to equal employment opportunity regardless of sex, race, religion, ethnicity, nationality, disability, age, sexual orientation or gender identity. We strongly encourage individuals from groups traditionally underrepresented in tech to apply. To help make a change, we sponsor bright women from disadvantaged backgrounds through their university degrees in science and mathematics. We collect diversity and inclusion data solely for the purpose of monitoring the effectiveness of our equal opportunities policies and ensuring compliance with UK employment and equality legislation. This information is confidential, used only in aggregate form, and will not influence the outcome of your application.