(Senior) Backend Engineer

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 (Senior) 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.

Our tech stack includes Go, AWS, Kafka, PostgreSQL, and Kubernetes, supported by a strong observability toolchain with Prometheus, Grafana, and Honeycomb. We also actively use AI‑assisted development tools such as Cursor, GitHub Copilot, and others.

SumUp’s engineering culture is built around ownership. We follow a “build it, run it, improve it” model, with strong observability and a focus on learning. Engineers have clear scope and autonomy, with decisions documented, reviewed, and made collaboratively.

The Vilnius team is a core part of the Global Bank domain. We own production systems, shape technical direction, and work closely with colleagues across SumUp’s global offices on critical merchant banking capabilities. Join our Vilnius Team today (Vilnius office).

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.

🌎 We’re a truly global team of 3200+ skilled professionals from 92+ countries, spread across 4 continents. Join the team from our Vilnius office.

🌈 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

🏖️ Time off: 25 days of paid leave, plus special holidays

🏥 Peace of mind: health insurance through Gjensidige and life & accidental coverage from Ergo

💪 Stay active: gym membership allowance to help you keep fit on your terms

📚Career growth and learning opportunities: We invest in your development through regular training, mentorship programs, SumUp University cohort and a yearly learning budget (2,000 EUR)

💡We take learning and experimentation seriously with Hack Days every second Friday, and entire global Hack Weeks.

🌴 Break4me: 1-month sabbatical after 3 years of service

🔗 Referral Bonus: earn additional rewards by referring talented individuals to join the SumUp team.

Compensation: From entry senior level 4,200 - 6,500 Euro Gross / month + 2000 EUR annual learning budget + Virtual Stock Options. Ranges may vary based on skills and experience.

About SumUp

At SumUp, we’re on a mission to empower small businesses around the world with simple, affordable tools to help them start, run, and grow. More than 4 million merchants across 37 markets trust us as their financial partner — and we’re just getting started.

We’re a global team of 3,000+ people from over 90 nationalities, united by curiosity, collaboration, and care. Our core values and culture shape everything we do, fostering inclusion, learning, and belonging.

• 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/or Kotlin and comfortable learning and working with other languages as needed, e.g. 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.)