Senior Backend Engineer (Golang) - Balance Management

Sumup

About the team: You’ll join SumUp’s Merchant Intelligence squad within the Engagement Mission — a newly formed team building foundational backend services that create a shared source of truth for product and merchant data across the business. The team is focused on two core services: * Product Catalogue Service — a global source of truth for all products SumUp sells across every market, including hardware, subscriptions, and software, as well as market-specific feature and settings configuration. * Merchant Intelligence Service — a centralized platform that aggregates merchant data from across the SumUp ecosystem, helping teams understand the full merchant journey through product adoption, hardware sales, health signals, support interactions, and marketing cohorts. By building these services, the squad is solving a company-wide challenge: product and merchant data is currently fragmented across multiple systems and teams, creating duplication, inconsistency, and reliance on manual workarounds. The Merchant Intelligence squad is building the platform foundations that will help teams across SumUp move faster and make better decisions with reliable, centralized data. As a Senior Backend Engineer, you’ll help design and build these services from the ground up. You’ll work closely with product, data, and engineering teams across SumUp to create scalable systems that are reliable, easy to integrate with, and valuable to a broad range of internal users.   What you’ll do: * Design, build, and evolve foundational backend services that create a shared source of truth for product and merchant data across SumUp, with a strong focus on scalability, reliability, and ease of adoption by internal teams * Develop and maintain robust APIs, data models, and integration patterns that enable teams across the business to access consistent and trustworthy product and merchant information * Build and improve data ingestion, aggregation, and event-processing pipelines that bring together signals from across the SumUp ecosystem into actionable merchant intelligence * Contribute to shaping the long-term architecture and strategy for the Product Catalogue and Merchant Intelligence services, helping establish platform capabilities that can be used across multiple systems and teams * Write high-quality, maintainable backend code following engineering best practices for testing, observability, and production readiness * Collaborate closely with product managers, data teams, and engineers across SumUp to identify needs, solve complex data challenges, and turn them into effective technical solutions * Work across squad and domain boundaries to support integrations, improve data consistency, and enable better internal tools, workflows, and merchant experiences * Help define engineering standards, technical direction, and ways of working in a newly established squad operating in a complex and evolving domain   You’ll be great for this role if you have: * Strong professional experience in backend engineering, building and operating reliable production systems * Solid experience with Golang and designing scalable backend services * Strong knowledge of API design, system design, and data modeling * Hands-on experience with Postgres or similar relational databases * Experience with AWS, Docker, Kubernetes, and infrastructure-as-code tools such as Terraform * Familiarity with event-driven architectures and message brokers such as RabbitMQ or Kafka * A strong ownership mindset, with the ability to work independently and navigate ambiguity * Clear communication skills and a collaborative approach to working across product, data, and engineering teams 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 🧑‍🔬 We take learning and experimentation seriously with Hack Days every second Friday, and entire global Hack Weeks. 🌈 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 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.   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.

Sumup

SENIOR BACKEND ENGINEER — GLOBAL EXPANSION ABOUT THE TEAM The Global Expansion Acquiring Squad is the engine behind SumUp's growth into new markets — integrating local payment acquirers, enabling merchant onboarding, and ensuring transactions flow reliably across countries like Mexico, Canada, New Zealand, and Australia. This role sits at the heart of that mission, owning critical backend systems while also shaping how the squad works — building AI agents and developer tooling that make the entire team faster and smarter. If you're a backend engineer who wants real ownership, enjoys working in ambiguous and complex environments, and is genuinely excited about teaching AI how your codebase works (not just using it for autocomplete), this role is for you. WHAT YOU'LL DO * Design and build scalable backend services in Golang and Kotlin, covering merchant onboarding, transaction processing, and reconciliation across multiple acquirers and markets * Lead technical investigations for new market launches and mentor engineers on the team * Configure and maintain AI coding assistants (Cursor, Copilot, Continue) with team-specific rules, framework conventions, and testing patterns — so generated code fits our systems, not generic templates * Build AI agents that automate repetitive development tasks, such as generating integration stubs, updating OpenAPI specs, and flagging idempotency violations * Keep documentation accurate and AI-accessible, so the team spends less time answering "how does X work?" and more time shipping YOU'LL BE GREAT FOR THIS ROLE IF… * Strong proficiency in Golang (primary) or a JVM language such as Java or Kotlin, with experience building distributed, fault-tolerant backend systems * Experience configuring AI coding assistants at a team level — defining rules, prompts, and context packages that produce consistent, framework-compliant output * Solid understanding of idempotency, retry policies, and transaction safety in payment or financial systems * Comfort working across multiple teams and domains simultaneously, navigating ambiguity and influencing without direct authority * A track record of taking ownership in complex, cross-functional environments where the scope isn't always clearly defined 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 €2,000 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

SumUp builds simple, affordable financial tools that help over 4 million small businesses across 37 markets get paid, manage their money, and grow. Beyond card payments, we offer a full suite of financial products - business banking, lending, invoicing, and money transfers - giving merchants everything they need in one place.  Our Transfers Excellence squad sits within SumUp's Global Bank, and owns the core services that power how merchants and consumers move money. E.g. IBAN-based transfers, money in and out, and peer-to-peer payments via the SumUp consumer app. With the high volume transfers per hour across our European markets. That means reliability isn't a nice-to-have - it's the baseline for us. Right now, the team is replacing a set of market-specific implementations with a single, unified global transfer platform that will serve Europe, the UK, Brazil, Chile, and eventually the US and Canada.  Join our team and contribute directly to platform-level architecture that will shape how SumUp moves money at scale - work that directly impacts millions of small businesses every day. Our tech stack includes Kotlin, Java, Go, a bit of Elixir, 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. 🎥 Get a feel for life in our Berlin office. WHAT YOU'LL DO * Build and maintain backend services that sit at the heart of SumUp's transfer infrastructure, taking end-to-end ownership from development through to observability, testing and production support * Contribute to the migration from market-specific services toward a unified global transfer platform, working across a mix of active services and legacy systems being decomposed * Raise well-scoped pull requests, conduct thorough code reviews, and help maintain high standards of code quality and test coverage across the team * Participate in incident reviews and the on-call rotation, taking accountability for the reliability of the services you build * Contribute to the technical roadmap by participating in architectural discussions and proposing solutions for complex, distributed systems challenges * Apply AI tooling to accelerate your own engineering workflows and contribute to raising the team's overall AI literacy YOU'LL BE GREAT FOR THIS ROLE IF… * Solid experience as a Backend Software Engineer in modern languages (e.g. Kotlin, Go, Java, etc.). Kotlin is the team's primary language and we also work with Java, Golang, and Elixir. * Solid understanding of distributed systems and event-driven architecture. Experience with async processing and messaging tools like Kafka (or similar). * Experience working with microservice architectures, including Spring Boot and event-driven patterns, alongside solid knowledge of relational databases and API design * Comfortable working in high-throughput, regulated environments where reliability matters. Defensive coding and attention to edge cases are part of the job * Clear communicator in written and spoken English, with a collaborative approach to working across global teams  * Curious about the product impact, not just the code. Comfortable thinking about how backend decisions affect the end 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.