Senior Backend Engineer - Accounts

Sumup

In the Global Bank tribe, we're building the infrastructure to provide merchants with a digital business account that empowers them to manage their banking needs. Our goal is to become the most popular banking partner for small merchants globally with an effortless, simple, and affordable experience. As part of the Bank Activation and Revenue team, you will join a high-impact growth engine within the bank. Our mission is to guide merchants in unlocking the most value out of their SumUp Business Account during their activation journey: we aim to convert 100% of SumUp’s ecosystem users into active Bank users. We own the critical journey from the moment a merchant opens an account until they understand how the business account can solve their business needs, making it part of their daily routine. To achieve this at scale, we are building a greenfield activation and engagement platform consisting of a series of initiatives and experiments to drive adoption and engagement of SumUp users with the business account. Your work will directly drive revenue by enabling seamless cross-selling of the entire SumUp product suite to millions of merchants. What You’ll Do * Build Greenfield Services: Design and implement the trifecta of services (Banners, Rewards, and Feature Toggles) from the ground up to power global product experimentation. * Drive Activation: Create the technical logic that tracks and incentivizes users through their first five meaningful transactions, ensuring a smooth path to becoming a long-term banking partner. * Own the Stack E2E: We follow a “build it, run it, own it” model. You will be responsible for the full lifecycle of your features, from architectural design to production monitoring. * High-Velocity Engineering: Participate in a culture of daily deliveries. We value moving fast, testing hypotheses, and iterating based on real-world data. * Bridge Client & Backend: Build robust APIs that power the mobile and web banking experience while managing complex asynchronous processing for rewards and incentives via Kafka. * Collaborate with Stakeholders: Work closely with other engineering teams across the Bank and the wider SumUp ecosystem to ensure our activation tools are easily integrable and highly scalable. You’ll be great for this role if * Strong technical foundation: Solid backend development experience in Golang, with interest in working across multiple languages (Kotlin, Elixir). You understand system architecture, object-oriented and functional design principles, data modeling, and API design (RESTful and event-driven). * Growth Mindset: You're curious and energized by complex problem-solving. You thrive in environments with fast iterations and careful design, where understanding the problem deeply is valued over rushing to delivery. You're excited by the opportunity to architect critical systems from scratch - like our new global banner service - and work in a team that follows a "build it, run it" model with daily deliveries. * Systems Pragmatist: You understand that supporting and evolving legacy systems is the foundation for future success. You take pride in making existing code better while ensuring new services are architected for the long haul. * Ownership and craft: You take full ownership of the software you ship, from design to production readiness. You value clean, maintainable code and continuously refactor to keep designs simple and scalable. * Communication: You can communicate complex technical trade-offs effectively to your fellow engineers and technical stakeholders. What You'll Achieve in 6 Months By your sixth month, you will have taken full ownership of one of our Rewards features and contribute to the Banners service. Banners service will be the primary engine for product discovery and cross-selling within the Bank app, enabling our team to run rapid-fire experiments that directly impact SumUp's bottom line. Any of the following would be considered a plus * Previous experience in a Growth-focused engineering team. * Experience building rules engines or Reward/Incentive systems. * Familiarity with the Fintech or Banking regulatory landscape. 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. * Be part of a global tribe building a banking solution from the ground up and delivering impactful solutions to the real-life problems of millions of SumUp merchants all over the world * 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) * Sabbatical program for tenured SumUppers * 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 * Health & wellness benefits: in-house fitness classes, gym in the office, subsidized Urban Sports Club and available psychotherapy sessions * A lot of other benefits such as Subsidized Public Transport Card, Kita placement assistance, Pension Scheme, Language Learning platform/courses etc. * Enrollment onto our virtual stock ownership program - you will own a stake in SumUp’s future success 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 valuesOpens in new window and cultureOpens in new window shape everything we do, fostering inclusion, learning, and belonging. SumUp is proud to be an Equal Employment Opportunity employer, committed to building a safe, respectful, and diverse workplace where everyone can thrive. 👉 Explore more about our culture on our careers site, or follow us on LinkedInOpens in new window and InstagramOpens in new window. 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. 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.

Sumup

SumUp builds simple, affordable financial tools that help small businesses get paid, manage their money, and grow. Beyond payments, we offer a number of financial products - including business banking, card products, lending, and invoicing — giving merchants everything they need to manage their payments and finances in one place. The Cards squad is a core part of that, owning the systems that power card issuing, lifecycle management, and transaction processing for merchants across Europe. We handle millions of card transactions every day, and we're now scaling those systems to support new product capabilities while laying the foundations for a more global, resilient platform. That's why we're growing the team and looking for a seasoned backend engineer who can take real ownership of complex, high-impact work. If you want to build systems that genuinely matter to small businesses and you're excited by the technical depth that comes with high-throughput, distributed architecture, this is the role for you. 🎥 Get a feel for our Berlin office here. WHAT YOU'LL DO * Own and lead the end-to-end delivery of backend services within the Cards EU domain, including observability, testing, and production support * Contribute to the technical roadmap by participating in architectural discussions and proposing solutions for complex, distributed systems challenges * Raise well-scoped pull requests, conduct thorough code reviews, and help maintain high standards of code quality and test coverage across the team * Collaborate closely with engineers in adjacent squads and with the product manager to shape and refine the squad backlog * Participate in incident reviews and the on-call rotation, taking accountability for the reliability of the services you build * Apply and champion AI tooling to accelerate engineering workflows, and help raise the team's overall AI literacy YOU'LL BE GREAT FOR THIS ROLE IF… * Solid, hands-on experience delivering production-ready backend services end-to-end, including testing, monitoring, and maintenance, on a modern cloud-native stack * Production experience with Kotlin and interest in working with a number of other languages (Java, Golang and Elixir) * Solid understanding of distributed systems, API design, data modelling, and working with relational databases * Hands on experience in containerisation, orchestration, and CI/CD practices * Ability to take an ambiguous product problem, define the technical approach, and lead it through to implementation with minimal guidance * Comfort working across teams and communicating clearly in written and spoken English in a professional setting * Genuine curiosity about the product domain — comfortable applying a backend lens during feature refinement and thinking beyond the code to understand how your work shapes the user experience 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 * 🚀 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 for your individual development, which can be used to attend conferences and/or advance your career through further education * 💶 A corporate pension scheme where we match up to 20% of your contributions * 🏖 Generous time off: enjoy 28 days of paid leave plus public holidays and special leave days * 🏃 Numerous other benefits such as Urban Sports Club subsidy, Kita placement assistance, subsidised office lunches * 🌴 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.

Sumup

ABOUT THE TEAM At SumUp, we're on a mission to bring merchants and consumers closer together and help local communities thrive. Within the Consumer Mission, we're building a rewarding banking experience that connects people to the small businesses they love while tackling some of the most technically demanding challenges in fintech: critical infrastructure migrations, smooth, uninterrupted payment experiences, seamless open banking integrations, and high‑availability banking systems that can’t afford to fail – all while enabling free transactions for our merchants. This role sits at the heart of that work — you’ll take real ownership of backend services that are close to our consumers, directly shaping their everyday experience, with impact that’s visible and felt across the entire platform. 🎥 Take a look inside our London office WHAT YOU'LL DO * Build and maintain Backend services for Core neobanking features including bank transfers, open banking, savings accounts, and payment processing * Take end-to-end ownership of features and projects, covering scoping, design, development, testing, deployment, and maintenance, leveraging Go along with Docker and Kubernetes for container orchestration. * Take ownership of critical infrastructure migrations — including our banking core system transitions — without disrupting live customer experiences * Collaborate closely with cross-functional teams including product, design, data science, security, and operations) to understand requirements, provide technical insights, and contribute to architecture discussions that ship meaningful banking features end-to-end * Support fellow developers and actively help build a collaborative, innovative engineering culture * Shape technical architecture and lead code reviews, helping define and promote best practices in code quality, testing, automation, and security to raise the overall engineering bar. * Build and integrate tools and systems that improve operational efficiency and reliability, with strong observability through monitoring, alerting, and hands‑on involvement in incident response and post‑mortems. YOU'LL BE GREAT FOR THIS ROLE IF YOU HAVE… * Strong proficiency in Go, Kotlin or Python, with a track record of building scalable, production-grade backend services * Experience working with cloud platforms (AWS or comparable) and container orchestration tools such as Docker and Kubernetes * Solid understanding of SQL and NoSQL databases, distributed systems, and the trade-offs that come with high-availability requirements * Comfort navigating complex, regulated environments — whether that's financial services, payments, or similarly high-stakes domains * A collaborative, product-oriented mindset with the ability to work independently, communicate clearly, and adapt when priorities shift Any of the following would be considered a plus * Previous experience in a Growth-focused engineering team. * Familiarity with the Fintech or Banking regulatory landscape. No visa sponsorship available with this position WHY YOU SHOULD JOIN SUMUP * 🌎 Opportunity to work with a truly global, multicultural team from our central London Bridge location. 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 * 🏖 Generous time off: enjoy 28 days of paid leave, plus bank holidays and special leaves * 📚 A dedicated annual L&D budget for attending conferences and/or advancing your career through further education * 🏥 Health matters: private health insurance, including optical and dental * 🚗 Life made easier: salary-sacrifice commuter benefits via Gogeta * 💼 Financial security: retirement scheme (SumUp matches 7% when you contribute 5%) * 🛡 Peace of mind: life insurance from MetLife for 2× your salary * 🌴 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. 📽 Want to bring this role to life visually? Check out our Global Employer Brand video library to add a video to your job post or create LinkedIn content. 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.