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

You'll be great for this role if…

• Solid proficiency in Node.js and TypeScript, with a track record of building and maintaining microservices
• Hands-on experience with React.js and a history of delivering maintainable, user-facing frontend features
• Comfortable working in a small, autonomous squad where ownership is expected from day one
• Experience reasoning about API design, incremental migration paths, and architectural trade-offs, including familiarity with event-driven concepts and tools such as Kafka or RabbitMQ
• Clear and confident communication skills, with the ability to articulate technical decisions and feedback to product, design, and cross-functional partners
• You are curious about this domain and are a continuous learner

Why you should join SumUp

Opportunity to work with 3000+ SumUppers globally on large-scale fintech products used by millions of businesses worldwide, from our Copenhagen office (Vesterport station (within 5 mins walking distance to Copenhagen central station). 

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

Health insurance and life insurance (available after 3 months of employment)

Company Pension Scheme: SumUp contributes 9% and you contribute 4.5% (available after 3 months of employment)

DSB Business Commuter Card available via pre-tax salary

Subsidised meals in the office canteen

Smartphone and subscription provided by SumUp

❤ Mental well-being support: access to licensed psychotherapists through SumUp Sessions, our confidential Employee Assistance Programme

Break4me: 1-month sabbatical after 3 years of service

Special leave days for life moments that matter, including birthdays, weddings, bereavement, and volunteering

Referral Bonus: earn additional rewards by referring talented individuals to join the SumUp team

You’ll attend global offsites, trips and/or hackathons (2023 , 2024 , 2025 and counting)

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.