Senior Backend Engineer - Golang

MEET URBAN SPORTS CLUB We are among the leading platforms for sports and wellness in Europe, dedicated to inspiring people to live active, healthy lives. With just one membership we offer access to thousands of fitness and wellness experiences across the continent. But what truly sets us apart? We believe our people are at the heart of everything we do. If you’re curious about how we work, what we value and how you might grow with us, explore our Culture Hub & Career Opportunities. *Big news: Wellhub and Urban Sports Club unite!* Urban Sports Club is now a proud part of Wellhub, creating a global wellbeing ecosystem. Together, we connect 39,000 corporate clients and 97,000 wellness partners across 18 countries, offering millions of people even more ways to stay active and take care of their health. THE OPPORTUNITY  We are looking for an experienced Senior Backend Engineer to join our Foundation Engineering team. In this role, you won't just be building features for a single product; You will be crafting the very core services that power the entire Urban Sports Club ecosystem. The Foundation team sits at the heart of our engineering organization. We are responsible for application-level, system-wide services that enable our multi-million user base to interact with our platform seamlessly. Your initial focus will be taking ownership of our critical Identity & Authentication services and our core Search backend, with exciting plans to architect and scale a centralized Notification service in the near future. You will act as a force multiplier for our entire engineering department. By designing highly scalable, secure, and performant internal APIs and services, you will enable other product teams to build fast and deliver value to our users. If you love deep-diving into system design, solving complex architectural challenges at the application level, and working with Golang, this is the perfect place for you. This position will be based in Berlin. WHAT YOU WILL DO * Own Core System Services: Architect, develop, and maintain high-throughput, application-level foundational services, focusing initially on identity/authentication and our core search backend service. * Drive Technical Evolution: Design and implement future shared services that support our vision for scaling the platform. * Enable Engineering Teams: Build clean, robust, and well-documented internal APIs and developer tools that empower other product teams to build features rapidly and securely. * Write Exceptional Code: Deliver highly testable, maintainable, and secure Golang code, taking full operational ownership of the components your team develops. * Foster Best Practices: Actively participate in the Urban Sports Club backend cluster, championing strong system design, modularized architecture, and automated testing across the company. * Collaborate Across Boundaries: Work closely with product owners, tech leads, and other engineering teams to understand their requirements and translate them into scalable, domain-agnostic solutions. WHAT YOU WILL NEED TO SUCCEED * You have extensive industry experience as a Senior Backend Engineer developing, optimizing, and troubleshooting large-scale applications written in Go (6+ years) * You have a solid understanding of (or direct experience with) core foundational services like Identity/Authentication protocols (e.g., Keycloak, OAuth2, OIDC) and search engines. * You possess a deep understanding of data structures, algorithms, and distributed system design. You know how to build modular, high-volume services that remain performant under heavy traffic. * You have a track record of designing clean, secure, and developer-friendly internal APIs that scale across multiple engineering teams. * You are comfortable working within cloud ecosystems (GCP/AWS) from an application perspective, understanding how to leverage cloud-managed services efficiently. * You break down complex, abstract problems into elegant software solutions. You communicate effectively with technical stakeholders and love mentoring others. * Experience with PHP is a nice-to-have. We have some legacy context here, so a familiarity with PHP helps if you need to understand existing logic during modernizations or integrations - but your primary daily weapon will be Go. * You engage, inspire, and motivate the people you work with. We like to have fun while building the backbone of a platform that inspires healthy living. WHAT’S IN IT FOR YOU  * Work on cutting-edge tech and influence the future of our stack: explore our Tech Radar * We're open to relocation and providing support with our visa agency * Free Urban Sports Club L Pro Membership + Friends and Family Discount: Stay active with free membership, plus discounts for friends and family. * Flexible Work Model: Enjoy a hybrid work setup, balancing on-site and remote work options to fit your lifestyle. * Extended Remote Work Options: Work up to 120 days remotely within the EU, the UK, and Switzerland, including 30 days outside the EU. You’ll also have the option to desk-swap at our other European offices. * WorkOUT Life Balance: Take advantage of 30 days of paid vacation annually, plus two additional days for volunteering, flexible working hours, and complimentary access to our mental health provider Open Up. * Personal Development: Receive an annual budget of €1,000 for professional growth, with regular internal training sessions and weekly German and English language classes. * Engaging Team Culture: Participate in regular team and company events along with wellness initiatives that help you stay productive, healthy, and engaged in a hybrid work environment. Urban Sports Club is committed to providing a friendly, safe, and welcoming environment for everyone who applies for a position or already works with us, regardless of their sports preferences, gender, gender identity and expression, sexual orientation, disability, physical appearance, body size, race, age, or religion (or lack thereof).

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.