Backend Engineer

About SumUp

We believe in the everyday hero. Those who have the courage to follow their passion and who have the strength and determination to realise their dreams.

Small business owners are at the heart of all we do, so we're creating powerful, easy-to-use financial solutions to help them run their businesses. With a founder’s mentality and a 'team-first’ attitude, our diverse teams across Europe, South America and the United States work together to ensure that small business owners can be successful doing what they love.

At SumUp, the Global Bank team builds the core infrastructure and services that give merchants a digital bank account, helping small businesses manage their money easily and reliably.

The Balance Management Squad sits at the core of the Global Bank Platform. Right now, our team is completing a major milestone: consolidating and modernizing our balance management system in Europe. The next big step is creating a global transaction history service; a single, shared platform used by all regions to give merchants consistent and transparent views of their financial activity.

As a Backend Engineer, you’ll help modernize existing systems while balancing innovation with stability, collaborate with teams across regions, and build reliable services that manage diverse markets with different regulations.

If you enjoy solving complex problems on high-load systems, are curious about banking, and are looking for a team that tackles challenges head-on, we’d love to hear from you.

What You’ll Do

• Build and evolve the SumUp’s core banking services that powers ledger operations and transactions, transforming our regional systems into a unified, scalable global platform.
• Tackle complex distributed systems challenges, ensuring resilient services that continue to perform under high transaction volumes.
• Support modernization initiatives by improving observability, adding test coverage, refactoring code for long-term maintainability, and gradually introducing new architectural patterns without disrupting live banking operations.
• Contribute to key architectural decisions - build ledger and transaction history systems from the ground up, ensuring a globally scalable banking solution for our clients.
• Collaborate with teams across Risk, Treasury, Finance, and Infrastructure to ensure smooth, compliant, and reliable global operations
• Take ownership from design to production, running the services you build, monitoring their performance, and continuously improving how we deliver high-quality software at scale.

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.

Why you’ll enjoy working at 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

You’ll be great for this role if

• You have solid backend experience building reliable, high-volume services and you think carefully about system design, APIs, data modeling, and how services interact.
• You are proficient in Golang and comfortable learning and working with other languages as needed, e.g. Kotlin or Elixir.
• You write maintainable, well-tested code, follow CI/CD best practices, and take responsibility for the software you build from development to production.
• You’re comfortable building, deploying, and running services in cloud environments like AWS using Docker and Kubernetes.
• You’re eager to learn about relational databases that perform well under load and maintain data consistency.
• You are a collaborator who enjoys working across regions, communicating clearly, exchanging feedback effectively, and making thoughtful technical decisions together.
• You have a curiosity for building reliable financial services and banking domain

It’s a plus if you have

• Knowledge of Elixir - some of our legacy services are written in Elixir, and while it's not essential, it would be useful if you've worked with it before
• Deeper PostgreSQL experience - we rely heavily on Postgres, so if you've done performance tuning, complex queries, or schema design, that's a plus
• Experience with event streaming platforms (Kafka preferred) and modern observability stacks (Grafana, Honeycomb, etc.)