(Senior) Full-Stack Engineer at Sumup

About the team: As part of the Acquisition Domain, you will work on building and scaling the systems that power how SumUp acquires and onboards merchants across all channels. The team operates within the Acquisition Tribe, focusing on developing end-to-end platforms and tools used by Sales, Partner Acquisition, and Account Management teams on a daily basis. You will contribute across the stack—designing and building backend services, APIs, and frontend applications that support acquisition workflows such as lead management, partner integrations, and onboarding processes. This includes developing user-facing interfaces that enable internal teams to interact with complex systems efficiently, while ensuring a seamless and intuitive experience. From a technical perspective, the team works with microservices architecture, event-driven systems, and modern frontend frameworks, handling high volumes of operational data and enabling real-time interactions across systems. You’ll collaborate closely with Product, Data, and other engineering teams to define scalable system designs, clean interfaces, and strong data contracts, while continuously improving system reliability, performance, and developer experience across the stack. What you’ll do: • Design, build, and maintain end-to-end features across backend services and frontend applications that support merchant acquisition and onboarding workflows • Develop and evolve scalable APIs and user-facing tools used by Sales, Partner Acquisition, and Account Management teams • Build intuitive frontend interfaces that simplify complex operational processes and improve internal user experience • Ensure data consistency and reliability across systems that handle leads, partner integrations, and acquisition pipelines • Write high-quality, maintainable code across the stack, following Platform standards and engineering best practices • Improve system performance, observability, and reliability, ensuring smooth operation of business-critical tools • Collaborate closely with Product, Data, and cross-functional teams to translate business needs into scalable, user-centric solutions You’ll be great for this role if you have: • 5+ years of professional experience, with strong proficiency in TypeScript and React • Hands-on experience building fullstack applications using modern frameworks such as Next.js, Remix, Nuxt, or similar • Strong experience designing and consuming RESTful APIs within a microservices environment, ideally supporting data-heavy or workflow-driven systems • Experience working with SQL and event-driven architectures (e.g. Postgres, Kafka), especially in systems that handle operational data such as leads, onboarding flows, or partner integrations • Good understanding of system architecture, software design principles, data modeling, and API design, with the ability to build scalable and maintainable systems • Experience building internal tools or user-facing applications that improve workflows and usability for non-technical users (e.g. Sales or Operations teams) • A collaborative mindset with strong communication skills, openness to feedback, and a clear sense of ownership over delivered features and systems Why you should join SumUp: 🌍 Opportunity to work with SumUppers globally on large-scale fintech products used by millions of businesses worldwide, from our Berlin 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 📚 A dedicated annual L&D budget of €2,000 for attending conferences and/or advancing your career through further education 🚀 Enrolment onto our VSOP program: You will own a stake in SumUp’s future success 💶 A corporate pension scheme where we match up to 20% of your contributions 🔄 30 Days Sabbatical: Enjoy the unique opportunity to take a well-deserved break with our 30 days sabbatical benefit after completing 3 years of employment with SumUp 🔗 Referral Bonus: Earn additional rewards by referring talented individuals to join the SumUp team 🚵🏾‍♂️ Numerous other benefits such as Urban Sports Club subsidy, Kita placement assistance, relocation assistance, subsidised office lunches About us: 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 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 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. 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. 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.