Backend Engineer - Cards

SumUp supports millions of small businesses around the world with simple, reliable financial products, from payments and banking to invoicing and more. 

As a Backend Engineer in the Cards Team, you’ll shape the future of payments by developing the systems that power card issuing, management, and transaction processing across Europe. Our systems handle millions of payments every day, and we’re evolving them into a global, scalable platform that can support merchants worldwide. Working with a modern cloud-native stack (AWS, Kubernetes, Docker, Kotlin, Elixir and Golang), you’ll build high-throughput, highly reliable services at significant scale.

If you’re passionate about solving complex engineering challenges in distributed systems, and want your work to directly impact millions of small businesses, then this is the perfect role for you.

What You’ll Do

• Collaborate with a global team to build a global banking platform, including high-level APIs, local implementations, and the infrastructure powering card issuing and payments across regions.
• Be part of the transformation efforts, helping turn monolithic services into decoupled, highly scalable, region-agnostic global banking services. 
• Design, implement, and iteratively improve backend services using Kotlin, Java, Golang, Elixir, PostgreSQL, Kafka.
• Strengthen reliability and observability by refining monitoring, logging, alerting, test coverage, and service health metrics.
• Improve our CI/CD pipelines to ensure fast, safe, automated deployments.
• Modernize and evolve existing systems, improving maintainability, introducing better patterns and driving incremental enhancements that make meaningful impact. 
• Solve meaningful challenges at scale, balancing innovation with the stability expected in the banking domain. 

You’ll be great for this role if 

• You have solid hands-on experience as a Backend Engineer and bring strong hands-on programming skills in Kotlin and Java, with an openness to work with additional languages such as Elixir, Java or Golang.
• You’re comfortable working with distributed or event-driven systems and are eager to deepen your knowledge of robust, fault-tolerant architectures, system design, data modelling and API design.
• You have experience working with PostgreSQL or other relational databases.
• You have some experience with event streaming platforms and messaging brokers like Kafka, or you’re excited to gain more practical experience with them.
• You’ve worked with modern cloud technologies (e.g., AWS) and have experience using containerization and orchestration technologies like Docker and Kubernetes.
• You’ve used CI/CD tools such as GitHub Actions or ArgoCD and understand the value of efficient and reliable deployment pipelines.
• You care about delivering high-quality, maintainable code, enjoy solving meaningful problems with others, and actively contribute to a team culture of learning and knowledge sharing.

Why you should join SumUp

• Be part of a company that values diversity and celebrates unique perspectives.
• Work with a global team of skilled professionals in an environment that fosters collaboration, learning, and growth.
• The opportunity to work on large scale fintech products used by millions of businesses around the world
• You’ll receive 25 days’ paid leave, plus 1 additional day for each year of employment.
• You can take up to 10 days’ educational leave to expand your skill set.
• Career growth and learning opportunities: We invest in your development through regular training, mentorship programs, SumUp University leadership cohort and a yearly learning budget (2,000 EUR)
• Enrollment onto our virtual stock ownership program - you will own a stake in SumUp’s future success
• Access to the SumUp Sabbatical, our Employee assistance program for mental health
• Join a global team where you belong: Check out our D&I Initiatives and Employee Resource Groups such as Pride Club, SumAfro, Neurodiversity, Grupos Mais, Women in Tech, and more
• We offer additional health insurance, a subsidized Multisport card, free shuttle buses from Joliot-Curie metro station and other great benefits.
• You’ll attend global offsites and/or hackathons

About SumUp

Be empowered to do more that matters.

At SumUp, we're on a mission to empower small businesses across the globe by providing a vast set of simple and affordable business tools to help them start, run, and grow their businesses. Today, over 4 million businesses in 36 markets rely on SumUp as their financial partner to manage payments, finance and customer relationships.

Our commitment to small businesses is reflected in our diverse team of over 3,000 SumUppers from over 90 nationalities, united by global collaboration and an innovative mindset. Our core values lay the foundation for who we are and what we stand for, shaping our work culture and driving our success. We foster an inclusivity and continuous learning culture, providing a safe space for personal and professional growth. Our differences make us unique and strong as we strive to create an environment where everyone belongs and feels supported, no matter how they identify.

SumUp is proud to be an Equal Employment Opportunity employer, actively seeking and embracing diversity in our workforce. We don't make hiring or employment decisions based on race, colour, religion or religious belief, ethnic or national origin, nationality, sex, gender, gender identity, sexual orientation, disability, age or any other basis protected by applicable laws or prohibited by company policy. Our commitment extends beyond recruitment to creating a safe and respectful workplace where harassment of any form is strictly prohibited.

Explore career opportunities with us and join a team driven by collaboration, innovation, and a shared vision of creating a world where everyone can build a thriving business. Discover more about our vibrant and inclusive work culture and how we work on our careers website, and follow our journey on LinkedIn and Instagram.