Senior Backend Engineer - Cards

Seasoned Backend Engineer (Cards Squad)

SumUp provides simple, affordable financial tools for small businesses to manage payments, money, and growth. Our Cards squad is central to this mission, managing card issuing, lifecycle, and transaction processing for merchants across Europe. We are scaling these critical systems to support new product capabilities and build a more global, resilient platform. We are looking for a seasoned backend engineer to take ownership of complex, high-impact work.

What You'll Do

• Own and lead the end-to-end delivery of backend services within the Cards EU domain, including observability, testing, and production support.
• Contribute to the technical roadmap by participating in architectural discussions and proposing solutions for complex, distributed systems challenges.
• Submit well-scoped pull requests, conduct thorough code reviews, and maintain high standards of code quality and test coverage.
• Collaborate closely with engineers in adjacent squads and product managers to refine the squad backlog.
• Participate in incident reviews and the on-call rotation, taking accountability for service reliability.
• Apply and champion AI tooling to accelerate engineering workflows and enhance team AI literacy.

You'll Be Great For This Role If You Have:

• Solid, hands-on experience delivering production-ready backend services end-to-end, including testing, monitoring, and maintenance, on a modern cloud-native stack.
• Production experience with Kotlin and an interest in working with other languages such as Java, Golang, and Elixir.
• A strong understanding of distributed systems, API design, data modeling, and working with relational databases.
• Hands-on experience with containerization, orchestration, and CI/CD practices.
• The ability to take an ambiguous product problem, define the technical approach, and lead it to implementation with minimal guidance.
• Comfort working across teams and communicating clearly in written and spoken English.
• Genuine curiosity about the product domain, with the ability to think beyond code to understand user experience impact.

Why You Should Join SumUp

• Global Impact: Work with SumUppers worldwide on large-scale fintech products used by millions of businesses from our Berlin office (office-first setup).
• Diversity & Inclusion: Be part of a workplace that values and promotes diversity, fostering an inclusive environment.
• Stock Options: Enrolment onto our Virtual Stock Option program, giving you a stake in SumUp's success.
• Learning & Development: A dedicated annual L&D budget of €2000 for conferences and further education.
• Pension Scheme: Corporate pension scheme with up to 20% employer match.
• Generous Time Off: 28 days of paid leave plus public holidays and special leave days.
• Other Benefits: Urban Sports Club subsidy, Kita placement assistance, subsidized office lunches.
• Sabbatical: 1-month sabbatical after 3 years of service (Break4me).
• Referral Bonus: Earn rewards for referring new talent.

About SumUp

SumUp empowers small businesses globally with simple, affordable financial tools. Over 4 million merchants in 37 markets rely on SumUp. Our diverse team of 3,000+ SumUppers from over 90 nationalities collaborates with an innovative mindset, guided by our core values. We foster inclusivity and continuous learning, ensuring a safe space for growth. SumUp is an Equal Employment Opportunity employer committed to diversity and inclusion.

Find out more about our culture and opportunities on our careers website, and follow our journey on LinkedIn, Instagram, and TikTok.

Job Application Tip: We encourage you to apply even if you don't meet 100% of the criteria, as we value potential for learning and development.