Senior Software Engineer - SRE Core Infrastructure

Senior Software Engineer – SRE Core Infra London (Hybrid) | Engineering | Full Time

The Role

PhysicsX is growing rapidly and so is the infrastructure that underpins our platform. We are building core infrastructure that is reliable, secure, scalable and reproducible across multiple cloud providers and on premises environments. As the platform evolves to serve increasingly complex engineering workloads, the foundational infrastructure layer becomes ever more critical.

We are looking for a Senior Software Engineer to join our Platform SRE Core Infrastructure team. This role is responsible for the design, provisioning and operation of the shared infrastructure that the entire PhysicsX platform depends on. You will work across infrastructure as code, Kubernetes cluster management, secrets management, GPU drivers, networking and multi tenancy architecture to ensure the platform is dependable, scalable and secure.

This is a role for an engineer who combines deep infrastructure expertise with a reliability engineering mindset and an appreciation for the developer experience of the teams that consume the platform.

What You Will Do

• Own the design and delivery of core infrastructure across multi cloud providers (GCP, Azure, AWS) and on premises environments using Terraform and Crossplane.
• Architect and operate Kubernetes clusters supporting both single tenant and multi tenant workloads, with a strong emphasis on isolation, performance and reliability.
• Define and implement infrastructure provisioning patterns using Crossplane compositions and Terraform modules, ensuring reproducibility and auditability across environments.
• Design and operate secrets management solutions, including dynamic secret provisioning, rotation and fine grained access control integrated with cluster identity.
• Manage and maintain GPU driver configurations and accelerated compute node pools, ensuring compatibility and performance for AI and simulation workloads.
• Own cluster networking design including CNI selection, Istio service mesh integration, ingress strategy and cross cluster connectivity.
• Implement and maintain vCluster based multi tenancy to provide strong workload isolation within shared infrastructure.
• Develop lightweight Kubernetes Operators or controllers where automation of infrastructure lifecycle tasks requires it.
• Establish SLOs and reliability targets for core infrastructure components and lead the response to production incidents.
• Partner with security and platform teams to enforce infrastructure governance, network policies and compliance controls.
• Contribute to and uphold engineering standards across the platform organisation.

What You Bring to the Table

• Kubernetes depth – 5 or more years of professional experience operating Kubernetes in production. You have a thorough understanding of cluster architecture, the scheduler, networking, storage and the API lifecycle. Kubernetes certifications such as CKAD, CKA or CKS are highly desirable.
• Crossplane expertise – significant hands on experience designing and operating Crossplane compositions, providers and managed resources in production environments.
• Terraform proficiency – strong experience authoring, structuring and operating Terraform at scale, including state management, module design and CI integration.
• Multi cloud and on premises – practical experience operating infrastructure across more than one cloud provider and on premises environments, with an understanding of the differences in identity, networking and storage.
• Multi tenancy architecture – experience designing and implementing both single tenant and multi tenant Kubernetes architectures, with strong views on isolation, resource governance and operational overhead.
• Secrets management – experience with tools such as Vault, External Secrets Operator or cloud native secret stores, including dynamic provisioning and rotation.
• Networking – solid knowledge of Kubernetes networking, CNI plugins, Istio service mesh and ingress patterns. Experience with cross cluster or hybrid connectivity is valuable.
• vCluster and virtual clusters – experience using vCluster or similar tooling to provide lightweight, isolated Kubernetes environments within shared clusters.
• GPU and accelerated compute – familiarity with GPU driver management, device plugins and the operational considerations of running accelerated workloads in Kubernetes.
• Kubernetes Operators – at least lightweight experience writing or extending Kubernetes Operators or controllers, ideally in Golang or Python.
• Software engineering capability – you are comfortable writing code to automate and extend infrastructure. Python and Golang are the primary languages used across the platform. Exposure to functional programming languages such as Erlang, Elixir or OCaml is appreciated.
• Platform engineering mindset – you think about infrastructure as a product consumed by engineering teams and prioritise usability, documentation and long term maintainability.
• Distributed systems experience – a solid grounding in distributed systems concepts, including failure modes, consistency and the operational challenges of running systems at scale.

Ideally

• Experience with GitOps workflows using tools such as Argo CD or Flux.
• Contributions to open source infrastructure or Kubernetes ecosystem projects.

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.

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.