(Senior) Backend Engineer - Golang

About the team: We are the Merchant Risk Intelligence team within SumUp’s Risk & Compliance tribe. We build systems that help protect SumUp and its merchants from fraud while supporting reliable, compliant business growth. Our team combines software engineering, machine learning, data science, product management and risk expertise. You will join a multidisciplinary group currently working across backend services, data products and AI-powered solutions. The team is growing its software engineering capabilities to develop Sentinel, our entity-level investigation and actioning framework, and to support broader risk and compliance use cases. You will bring dedicated Golang expertise to the team while also contributing to Python-based services and AI-agent initiatives. We value pragmatic engineering, thoughtful collaboration and the ability to balance delivery speed with security, reliability and long-term maintainability. What you’ll do: Develop new functionality and support existing services across the tribe’s codebase, primarily using Go Contribute to the continued development of our in-house merchant risk decision framework, taking it beyond its MVP and enabling new fraud prevention, risk and compliance use cases. Design, build and maintain reliable distributed systems and backend services. Work closely with product managers, data scientists, machine learning engineers, fraud strategy teams and operational stakeholders to turn complex problems into practical solutions. Help shape technical direction, service boundaries and system design decisions across the team. Contribute to Python projects, including AI-agent initiatives, as you build a broader understanding of the team’s systems. Participate in code reviews, testing, monitoring and continuous improvement of production services. Use AI-assisted development tools thoughtfully to deliver meaningful features faster without compromising code quality, security or maintainability. Be open to participating in an on-call