Java Team Lead

SumUp gives small businesses the tools they need to get paid, manage their money, and grow - today, over 4 million merchants across 37 markets worldwide rely on SumUp to do exactly that. The Bank Web squad sits within SumUp's Bank domain and owns the web experience across our banking surfaces - from the business account dashboard that merchants use daily, to the back-office tooling that powers the support teams behind them. The team has a clear mission: make Bank Web a genuinely first-class platform, on par with our mobile applications in quality, reliability, and performance. Joining now means being part of a team that’s at a key growth point - modernization work, growing scope across markets, and making architectural decisions that will shape how millions of merchants experience SumUp's banking products. 👉 Take a look at our Sofia office What you'll do * Build and own features end-to-end across our web banking surfaces - from scoping and component implementation through testing, observability, and production maintenance * Work across the full stack - including defining API contracts, working with backend proxies, and integrating with the services that power our banking platform * Contribute to modernisation efforts, including architectural improvements, component refactoring, and stack migrations that reduce technical debt and accelerate future delivery * Review peers' pull requests with attention to UI consistency, accessibility, and frontend best practices * Participate in production support and incident reviews, helping to strengthen the squad's operational resilience across its web domain You'll be great for this role if… * Strong experience with React, TypeScript, with a track record of delivering production-ready features end-to-end -not just isolated UI components * Genuine full-stack capability: Experience defining API contracts, working with backend proxies, and owning integrations, not just consuming them; backend experience in Node, Kotlin, Java, or Golang is valued * Solid understanding of frontend architecture, component design patterns, state management, and how frontend applications connect to backend services * Experience writing and maintaining frontend tests (unit, integration, snapshot, end-to-end) and a genuine care for code quality and reliability * Comfort navigating a complex, multi-stack codebase. React and TypeScript are core to this role, while our broader ecosystem also includes Node.js, Kotlin, Java, Go, Angular, AWS and Kafka. Prior experience with all of these is not required, but familiarity with most of them is a plus * Curiosity about complex domains - banking products have intricate user flows and edge cases, and you enjoy digging into them to find the right solution * Familiarity with CI/CD practices and getting changes safely to production; exposure to AI tooling to augment engineering workflows is a plus 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 setup * 🌈 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.   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.

At SumUp, we empower millions of small businesses worldwide. Our Payments Tribe is at the heart of this mission, processing billions of transactions across 36+ countries each year. We're building reliable, secure, and scalable systems that truly make a difference. THE TEAM:  Our robust payments processing platform has powered SumUp’s global business for over a decade. The Online Payments team, now a key part of our Payments Tribe, is responsible for facilitating all Card Not Present (CNP) transactions, ensuring our merchants can accept payments seamlessly online. This entire ecosystem is developed in Sofia by autonomous, cross-functional, and co-located squads, each owning their part of the platform end-to-end. We are currently in an exciting phase of scaling and improving existing products, while also developing innovative new ones. You'll make a significant impact by improving and co-creating our existing and new microservices architecture platforms, tackling complex scaling and new development challenges. Scalability and high availability are always at the forefront of our work. You'll join a team that values solid engineering and impactful solutions. You'll contribute to the design and development of our Golang-based Online Payments platform, working with cutting-edge tech and directly influencing our product. OUR TECH STACK:  We believe in using the best technology for each challenge, fostering an environment of continuous learning and exploration. Our current ecosystem includes Golang, Kafka Streams, PostgreSQL/RDBMS, AWS, microservices architecture. WHAT YOU'LL DO: * Co-design and develop high-performance, secure backend services for our Online Payments Platform  * Participate in API design and implementation for both internal and external integrations. * Deliver business value through backend decisions and active participation in product discussions. * Ensure high code quality, comprehensive test coverage, and clear documentation. * Optimize application performance and scalability through active monitoring and proactive solutions. * Collaborate closely with other software developers, QA, and DevOps engineers for smooth deployment, continuous integration, and support. * Actively participate in code reviews, fostering a culture of continuous improvement. YOU'RE A GREAT FIT IF YOU HAVE: * Solid experience as a Backend Software Engineer in any modern language(e.g. Go, Java, Python, Kotlin, etc.). We care more about how you think and design systems than the specific language you use. * Experience with PostgreSQL/RDBMS and distributed, fault-tolerant systems. * A genuine passion for clean, maintainable, and testable code. * Interest in using AI as part of your development workflow. * A good understanding of software architecture and application design. * Bonus points for: Experience with Docker and/or Kubernetes, Kafka/other messaging systems, Unix/Linux environments, and DevOps practices (CI/CD). WHY JOIN SUMUP? * Make an impact on a global scale - our systems serve millions of merchants * Learn from experienced engineers while working on complex, real-world problems * Be part of a tech-agnostic team that uses the right tools for the job * Collaborate with SumUppers worldwide on large-scale fintech products used by millions, based in our Sofia office (office-first setup). * Access a €2,000 annual L&D budget to attend conferences or advance your career through education. * Enjoy 25 days of paid leave (increasing with tenure), plus paid vacations for special occasions and a 1-month sabbatical every 3 years. * Benefit from extra perks like health and life insurance, co-sponsored Multisport cards, childbirth/adoption bonuses, discounts, a referral program, 100 EUR monthly food vouchers, 40 EUR flexible benefits, and more. Please note: This role requires the right to work in Bulgaria. We are currently not able to support visa applications or relocation for this position at this time. About us: SumUp is a leading financial technology company, founded in 2012 with the goal of empowering small businesses around the globe. We’re the financial partner of choice for more than 4 million merchants in over 35 markets. We collectively build, plan and fine-tune the technology that drives SumUp and empowers small businesses around the world. 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 business. 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. SumUp is an Equal Employment Opportunity employer that proudly pursues and hires a diverse workforce. SumUp does not make hiring or employment decisions on the basis of 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. SumUp also strives for a healthy and safe workplace and strictly prohibits harassment of any kind.   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.