Senior Software Engineer - Platform Runtime

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:

Equity options – share in our success and growth.
10% employer pension contribution – invest in your future.
Free office lunches – great food to fuel your workdays.
Flexible working – balance your work and life in a way that works for you.
Hybrid setup – enjoy our Shoreditch office while keeping remote flexibility.
Enhanced parental leave – support for life's biggest milestones.
Private healthcare – comprehensive coverage.
Personal development – access to learning and training to help you grow.
Work from anywhere – extend your remote setup to enjoy the sun or reconnect with loved ones.