Lead FullStack Engineer

In short At On, technology is more than just support—it’s a catalyst for movement. As we expand our global retail footprint, we’re reimagining the Point of Sale experience to be as premium, customer-centric, and innovation-driven as our brand. We’re seeking a Full-Stack Engineer to help power the next generation of POS platforms—solutions that enable frictionless checkout, real-time inventory, omnichannel excellence, and seamless integration across our digital and physical retail ecosystems. Based in Berlin, you’ll be a core contributor on the Retail Experience team, building modern interfaces and performant backends that bring our retail vision to life. This is a hands-on engineering role with broad technical ownership—spanning frontend (React/TypeScript), backend (Node.js or equivalent), and API orchestration. If you’re excited by streaming platforms, composable commerce, and building experiences that directly impact athletes and customers around the globe, let’s move together. Your mission POS Frontend & Backend Development: Build intuitive, fast, and resilient user interfaces using React, TypeScript, and modern frontend tooling Develop scalable backend logic (Node.js or equivalent) to support retail data flows, system integrations, and business rules Systems Integration & API Engineering: Integrate with REST and GraphQL APIs across commerce, ERP, payment, and inventory systems Build secure, observable services that handle real-time and asynchronous data exchange Work with mobile-first and PWA design principles to support a variety of in-store form factors Platform Architecture & Resilience: Help shape the architecture of On’s POS platforms with a focus on flexibility, scale, and high availability Contribute to platform observability and monitoring using industry-standard tooling Implement robust testing across unit, integration, and end-to-end layers—automating quality at every stage Cross-functional Collaboration: Work closely with product stakeholders to bring ideas to life Influence technical decisions during vendor evaluations and rollout phases Impact roadmap decisions by sharing technical insights and platform implications Participate in agile rituals, code reviews, and engineering best practices Your story 5+ years of full-stack development experience in high-performance, customer- or employee-facing applications Deep expertise in React, TypeScript, and modern JavaScript (ES6+) Proficient backend development skills—Node.js preferred, but open to equivalent modern stacks Strong understanding of REST and GraphQL APIs, including authentication, caching, pagination, and error handling Experience designing and building retail or commerce workflows such as checkout, loyalty, or order sync Familiarity with headless commerce, microservices, and composable architectures Solid understanding of testing methodologies: unit, integration, component, contract, and end-to-end Hands-on experience with CI/CD pipelines, Git workflows, and Agile methodologies Comfortable working in a fast-paced, evolving environment with cross-disciplinary teams 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.