On - Senior Lead – Staff Site Reliability Engineer - London

Team for Career Site

Technology

In short

At On, we believe technology should move as fast as a runner. We are building the foundation that allows our engineering organization to scale, innovate, and deliver value without friction. We are looking for a Staff Software Engineer to join the Developer Experience (DevEx) team.
In this hands-on IC role, you will build the platform that empowers dozens of technology teams to build, ship, and operate services effortlessly. You will be the architect and primary builder of our “Golden Path,” ensuring that speed, safety, and reliability are baked into every developer’s workflow.

Your mission

– Engineer the Golden Path: Design and implement highly automated CI/CD pipelines (GitHub Actions) and common templating (Typescript/Node) systems that allow a developer to go from “idea” to “production-ready service” in minutes.
– GraphQL Infrastructure: Act as a core contributor to our central Apollo GraphQL API Gateway. You will manage the supergraph composition, runtime stability, and schema governance standards to ensure a consistent contract for all consumers.
– Build the Internal Developer Platform (IDP): Develop our Cloud Abstraction Layer and Developer Portal. This includes building self-service tools, CLIs, and service catalogs that reduce cognitive load for engineers.
– SRE & Observability: Integrate “secure-by-default” practices and robust observability into the platform. You’ll build dashboards (NewRelic) and monitoring patterns that provide teams with deep insights into their service health.
– Technical Excellence & Advocacy: Conduct code reviews, write high-quality documentation, and advocate for DevEx best practices across the organization.
– Friction Reduction: Actively hunt for bottlenecks in the software development lifecycle. Whether it’s a slow build or a complex deployment process, you are responsible for fixing it.

Your story

– Product Thinking: You treat internal developers as your customers. You listen to their pain points and iterate on the platform based on real-world feedback.
– Infrastructure as Code: You are comfortable with Terraform and Kubernetes (GCP experience is a plus), treating infrastructure with the same rigor as application code.
– Automation Mindset: You are passionate about CI/CD (GitHub Actions) and building developer tooling (CLIs, SDKs, or Portals).
– AI-Augmented Engineering Workflows: You leverage the latest agentic coding tools to 10x your productivity, blending deep technical principles with AI-assisted workflows. As a power user of AI, you orchestrate complex builds and bypass boilerplate to deliver robust, scalable code at pace, ensuring our TypeScript/Node.js environment remains lean and efficient.
– Architectural API Design: Extensive experience in crafting robust API contracts with a focus on GraphQL Federation; familiarity with the Apollo tech stack is highly regarded.
– Data-Driven: You understand DORA metrics and DevEx signals, using them to measure the success of the tools you build.

Meet the team

The Developer Experience team serves as the bridge between infrastructure and product. We don’t just measure “uptime”; we measure “time to value.” As a Staff Engineer on this team, you will be at the heart of our engineering culture, defining the standard for how software is built and delivered at On.