Senior Fullstack Engineer (NodeJs)

Location: Copenhagen, Denmark

The Global Bank tribe at SumUp, builds the financial tools that help small businesses manage their money more confidently, including Expenses and Making Tax Digital, two products that sit at the heart of SumUp's accounting and compliance offering. In this role you will join a small, senior squad, at a genuinely exciting moment: we starting with Making Tax Digital in the UK, where merchants can now submit Income Tax assessments digitally, SumUp's vision is to expand this into a full suite of Accounting tools - covering Income Tax assessment, VAT submission, and financial reporting across multiple markets. This is genuinely early-stage, high-impact work, and the Expenses and MTD squad is where it begins. We are looking for a Senior Fullstack Engineer who can own end to end delivery work across both the frontend and backend. You'll work closely with two senior engineers, a Product Manager, a Designer, and an Engineering Manager - with the reach and resources of a global 200 person tribe behind you, and product impact at scale. ### What you'll do

• Build and maintain full stack features across the Expenses and MTD products, working across the React.js frontend and Node.js/TypeScript backend
• Contribute to the major initiative to integrate Expenses directly into the Business Account transaction history, including API refactoring and frontend changes
• Take ownership of backend service reliability within the squad, including CI/CD workflows, Kubernetes deployments, and observability tooling
• Collaborate with Product, Design, and cross-functional squads to deliver clean, testable, and maintainable code, with a focus on user experience
• Participate in code reviews, contribute to architectural decisions, and help evolve the squad's engineering practices