Senior Backend Engineer (Java) - Payments… at SumUp Payments · Sofia

Senior backend engineer Java – Payments tribe 📍 Sofia | Full-time | Office-first Check out our Sofia office WHO WE ARE: We’ve come a long way from our origins as a small startup. Today, we’re a truly global fintech company, with over 3000+ people from 80 nationalities, spread across 22 offices on 4 continents. And we’re growing and diversifying faster than ever before. SumUp enables businesses to get paid easily, process orders quickly, sell online instantly and manage their money more efficiently. We create the tools businesses need to make their business and their customer experience thrive. The Team The Settlement Squad sits within SumUp's Payments Tribe and is responsible for the infrastructure that moves real money — managing settlement processes, banking integrations, and the financial controls that keep payouts running accurately across our merchant base. We're at a pivotal moment: alongside maintaining a business-critical legacy system, we're building a brand-new event-driven platform designed to scale across multiple markets and teams. This role is central to that transition — you'll help shape the architecture of a system where the quality of your decisions has a direct, measurable impact on SumUp's operations and reputation. What you'll do Build and maintain integrations with banking partners that execute payouts to merchant bank accounts Contribute to the design and development of a new event-driven microservices platform, moving away from legacy architecture Work on reconciliation processes, prefunding calculations, and safeguarding flows for our payment operations teams Develop and maintain operational tooling used by Payment Operations to manage day-to-day payout jobs Participate in code reviews, architectural discussions, and on-call rotations to keep our systems healthy and reliable You'll be great for this role if you have: Strong hands-on experience with Java and Spring Boot, building and maintaining production-grade backend services Strong experience across thefull SDLC (build → ship → operate → improve) Experience working with distributed systems and microservices architecture across the full software development lifecycle Comfort working autonomously and making sound technical decisions without needing heavy direction A collaborative communicator who can engage effectively with both technical teammates and non-technical stakeholders Exposure to payments, fintech, or other regulated, transaction-heavy domains is a plus — though a genuine curiosity for the space matters just as much Nice to have: Kafka / event-streaming experience. Docker, Kubernetes, AWS. Payments / settlement / reconciliation domain knowledge. Experience building a platform or services from scratch. Our current stack (subject to evolution) Java (Spring Boot), Kafka Streams, PostgreSQL/RDBMS, REST, plus operational tooling and internal UIs. Why you should join SumUp Opportunity to work with SumUppers globally on large-scale fintech products used by millions of businesses worldwide, from our modern Sofia office. This involves an office-first set up 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 and 10 paid days of educational leave which can be used to attend conferences and/or advance your career through further education Generous time off: 25 days of paid leave, plus one extra day per year of service (up to 35), along with public holidays and special leave options Peace of mind: additional health insurance and life insurance Stay active: on-site yoga and a co-sponsored Multisport card offering access to hundreds of sports facilities Meal support: benefit from a tax-free food voucher program plus flexibility via our Re:Benefits platform Easy commute: free shuttle buses connecting directly to Joliot-Curie metro station Break4me: 1-month sabbatical after 3 years of service Referral Bonus: earn additional rewards by referring talented individuals to join the SumUp team 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 simple and affordable tools that allow them to thrive. Today, over 4 million businesses in 37 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 inclusivity and a 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. Discover more about our culture and opportunities on our careers website, and follow our journey on LinkedIn, Instagram, and TikTok. Job Application Tip We recognise that candidates feel they need to meet 100% of the job criteria in order to apply for a job. Please note that this is only a guide. If you don’t tick every box, it’s ok too because it means you have room to learn and develop your career at SumUp.