Lead Backend Engineer (Typescript)

ON; Greater London; On-site; GBP 70,000 - 90,000; Full time

Job summary

A leading sports brand in Greater London is searching for a Lead/Senior Backend Engineer to enhance its customer communication platform. The ideal candidate has over 8 years of backend experience and is fluent in Ruby and Node.js. This role involves shaping APIs and leading design initiatives, as well as mentoring other engineers. The organization promotes a values-driven culture focused on growth, innovation, and collaboration among diverse teams across locations.

Benefits

Supportive, team-oriented atmosphere

Access to personal self-care for physical and mental well-being

Opportunities for continuous learning and growth

Qualifications

• 8+ years of backend experience with complex distributed systems.
• Fluency in Ruby and Node.js; experience with TypeScript and NestJS a plus.
• Strong experience with event-driven systems and resilient APIs.

Responsibilities

• Shape and evolve the customer communication platform.
• Lead design and rollout of complex systems and architectural decisions.
• Mentor engineers and influence organizational culture.

Skills

Ruby

Node.js

API design

Kafka

Container orchestration

Job description

Our Direct to Consumer business is performing and growing strongly, which is why we - within the Customer Communication Platform team in Commercial Technology at On - are looking for a Lead/Senior Backend Engineer to scale On’s online business to the next level. Our newly created team is focused on providing a customer communication platform product. As an experienced engineer, you will be responsible to design, build, deploy, test and operate our digital services. You will be working in our office in London and collaborating closely with the cross‑functional teams across locations.

Your Mission

• You will shape and evolve the customer communication platform by providing APIs, real‑time events and documentation to reduce the cognitive load and enable multiple stream‑aligned teams to rapidly deliver premium, personalized experiences across all consumer touch points.
• You will lead the design and rollout of complex systems, guide architectural decisions across teams through RFCs, and ensure our platforms are built for long‑term growth and operational excellence.
• You will act as an expert in the given technology area, leverage best‑in‑class engineering practices including continuous integration and deployment, code reviews, high test coverage and observability.
• You iteratively deliver high‑value, high‑quality solutions while balancing speed, scalability, and reliability.
• You collaborate effectively across diverse teams and stakeholders, driving alignment between product, design, and engineering.
• You will engage in the engineering community by sharing knowledge, mentoring your team mates, receiving / providing feedback, or growing our team by supporting the hiring.
• You act as a mentor and technical reference for senior engineers, fostering a culture of learning and growth.

Your story

• You have 8+ years of backend experience designing, building, testing, releasing, maintaining, scaling, and evolving complex distributed systems with a strong problem‑solving mindset striving for excellence and taking full accountability across teams.
• You are fluent in Ruby and Node.js (TypeScript and NestJS as a plus) ecosystems and experienced with API design (GraphQL/REST).
• You bring strong experience with event‑driven systems (Kafka, RabbitMQ or similar), distributed data architectures and delivering resilient, observable APIs (New Relic).
• You have mastered automated testing, TDD, and performance debugging tools; you are hands‑on with operating the infrastructure on AWS or GCP and container orchestration (Kubernetes).
• You have led architectural initiatives, guided system design through RFCs, and influenced engineering strategy beyond your immediate team.
• You lead and coach teams through incident response, root cause analysis, and long‑term reliability improvements.
• You communicate with clarity and empathy, guiding stakeholders through complex trade‑offs and aligning multiple teams around shared goals.
• You mentor engineers and influence organizational culture, creating an environment of feedback, growth, shared accountability, and technical excellence.
• You think product‑first — connecting technical decisions to customer and business outcomes, applying holistic thinking and delivering for impact using experimentation.

Attributes of a successful candidate

• Action‑Oriented: Anticipates opportunities that advance organizational goals and mobilizes others to act with urgency and clarity.
• Organization‑focused: Builds trusted relationships across teams, creating alignment and shared purpose.
• Alignment‑driving: Connects technical decisions to organizational strategy and ensures consistent execution across domains.
• Leads through Ambiguity: Provides clarity and confidence across teams in uncertain or high‑pressure situations.
• Develops Others and Self: Models continuous learning while fostering growth across the organization through mentoring, coaching, and structured feedback.

About the Team

As you might expect from a running brand, the wider E‑Commerce team at On is a fast‑paced place to be. You will work in the diverse Customer platform team as part of Commercial Technology. You will collaborate with roles including Software Engineers, QA Engineers, Product Managers, Data Analytics, Marketing and others of stream‑aligned or platform teams that are located in Berlin, Zurich and London.

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.