Senior Frontend Engineer – Sell Online

You'll join the Sell Online Tribe, building frontend features for payment links, gift cards, and online checkout products. You'll work with React and Next.js in a cross-functional team, taking ownership of the frontend and contributing to integration products and SDKs.

• Build and maintain frontend features across payment links, gift cards, and online checkout products, writing clean, testable, and maintainable code
• Contribute to the development and upkeep of our integration products and SDKs, used by both internal teams and external partners
• Take part in technical planning, design reviews, and sprint ceremonies - bringing your perspective on estimations, trade-offs, and improvements
• Help reduce tech debt and improve application performance, observability, and accessibility as a foundation for future delivery
• Monitor live services and respond to issues, providing redundancy for customer support requests reaching the team

• 5+ years of experience in TypeScript and JavaScript, with hands-on experience building production-grade React and Next.js applications (including SSR and app router patterns)
• Experience writing unit, integration, and end-to-end tests using tools like Jest, Vitest, or React Testing Library
• Comfortable working within CI/CD workflows and collaborating in agile environments (Scrum or Kanban)
• Experience with UI libraries such as Radix or shadcn, and a solid understanding of accessibility and UX best practices
• A product mindset - someone who cares about the value delivered to merchants, not just the code written to get there, and who can work autonomously to drive complex features end-to-end

• Opportunity to work in a truly global, multicultural team from our open, vibrant Cologne office, located in the heart of the city. This involves an office-first setup
• Commitment to Diversity and Inclusion: be part of a workplace that values and promotes diversity, fostering an inclusive environment where everyone's perspectives are respected and embraced
• Enrolment onto our Virtual Stock Option programme: you will own a stake in SumUp's future success
• A dedicated annual L&D budget of €2000 for your individual development, which can be used to attend conferences and/or advance your career through further education
• Generous time off: enjoy 28 days of paid leave plus public holidays and special leave days
• Commute made easy: subsidised mobility options like discounted transport tickets or bike leasing
• Stay active: access to fitness via Urban Sports Club, mostly covered by SumUp
• Financial health: a corporate pension scheme with SumUp contributing an extra 20% on top of your contribution
• Employee perks: get discounts across products and services via our Corporate Benefits platform
• Break4me: 1-month sabbatical after 3 years of service
• Referral Bonus: earn additional rewards by referring talented individuals to join the SumUp team