Senior Backend Engineer - Identity Lifecycle

You'll join one of the teams within SumUp's Identity Lifecycle Mission, working on some of the most critical building blocks behind the merchant journey, from onboarding and identity verification to KYC/KYB, regulatory data collection, and managing customer identity throughout the entire lifecycle. As a Senior Backend Engineer, you'll have the opportunity to shape how the identity platform evolves, modernise critical services, and help build foundations that can support new regulations, markets, and product requirements.

What you'll do

• Design, build, and operate scalable backend services, APIs, event-driven workflows, and system integrations.
• Build reusable capabilities that power merchant onboarding, identity verification, and KYC/KYB regulatory data collection.
• Drive reliability and resilience across critical services through better observability, failure handling, incident response, and long-term risk reduction.
• Work primarily with Go, while maintaining and progressively modernising existing services written in Java.
• Evolve domain models and service boundaries while reducing legacy complexity, duplicated logic, and tightly coupled integrations.
• Own your work end-to-end, from technical design and implementation to rollout and production follow-up.
• Work across team and domain boundaries, turning ambiguous product and regulatory requirements into clear, scalable technical solutions.
• Review code and designs, mentor engineers, and help raise engineering standards across the mission.

What you'll need

• Strong professional experience building and operating production backend systems with high business impact.
• Experience working with Go and Java and confidence in maintaining and evolving existing Java services.
• Strong knowledge of API design, distributed systems, asynchronous processing, data modelling, testing, and system design.
• Experience with event streaming platforms such as Kafka and modern observability tools such as Grafana or Honeycomb.
• Experience deploying and operating services in cloud environments such as AWS, ideally with Docker and Kubernetes.
• A strong ownership mindset, with the ability to take complex problems from definition through to production.
• Experience improving the reliability of business-critical systems and turning recurring incidents into lasting engineering improvements.

Nice to have

• Experience in fintech, payments, KYC/KYB, identity verification, or regulatory systems.
• Experience translating regulatory and compliance requirements into clear, scalable engineering solutions.

What they offer

• Annual L&D budget of €2,000 for conferences and further education
• VSOP program: ownership stake in SumUp's future success
• Corporate pension scheme matching up to 20% of contributions
• 30 days sabbatical after 3 years of employment
• Hack Days every second Friday and global Hack Weeks
• Urban Sports Club subsidy, Kita placement assistance, relocation assistance, subsidised office lunches