Senior Site Reliability Engineer - Edge

Company: FashionUnited Group

Location: London

Posted: March 21st, 2026

In the dynamic landscape of On, our technology thrives much like a spirited runner: always moving, always improving. We are building the foundation that allows our engineering organization to scale, innovate, and deliver "Wow" to athletes worldwide. To power this mission, we are seeking a Senior Site Reliability Engineer (SRE) - Edge who understands that reliability, security, and performance start at the transport layer.

You won't just manage a CDN; you will own the architecture and performance of our global entry points, including our Apollo GraphQL API Gateway. You will leverage expert‑level knowledge of HTTP/S, TCP, and DNS to optimize for global throughput. This is a hands‑on senior role where you will troubleshoot advanced network bottlenecks, design our future content delivery strategy, and act as the technical authority for our Web Application Firewall (WAF), bot mitigation, and standardized service authentication.

Your mission

Your story

Meet the team

You will be joining the Platform Foundations group, a high‑impact collective of engineers dedicated to building the "Engine" of On's technology. We manage our cloud infrastructure, Developer Experience (DevEx), and the Edge. We are a global team that values a "lead‑by‑example" culture. You will work alongside Staff and Principal engineers to bridge the gap between infrastructure and product, ensuring our technical investments directly accelerate the velocity of On’s mission.

What we offer

On is a place that is centered around growth and progress. We offer an environment designed to give people the tools to develop holistically – to stay active, to learn, explore and innovate. Our distinctive approach combines a supportive, team‑oriented atmosphere, with access to personal self‑care for both physical and mental well‑being, so each person is led by purpose.

On is an Equal Opportunity Employer. We are committed to creating a work environment that is fair and inclusive, where all decisions related to recruitment, advancement, and retention are free of discrimination.

England, United Kingdom of Great Britain and Northern Ireland

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