Fullstack Engineer

SumUp gives small businesses the tools they need to get paid, manage their money, and grow - today, over 4 million merchants across 37 markets worldwide rely on SumUp to do exactly that.

The Bank Web squad sits within SumUp's Banking domain and owns the web experience across our banking surfaces - from the business account dashboard that merchants use daily, to the back-office tooling that powers the support teams behind them. The team has a clear mission: make Bank Web a genuinely first-class platform, on par with our mobile applications in quality, reliability, and performance.

Joining now means being part of a team that’s at a key growth point - modernization work, growing scope across markets, and making architectural decisions that will shape how millions of merchants experience SumUp's banking products.

👉 Take a look at our Sofia office

What you'll do

• Build and own features end-to-end across our web banking surfaces - from scoping and component implementation through testing, observability, and production maintenance
• Work across the full stack - including defining API contracts, working with backend proxies, and integrating with the services that power our banking platform
• Contribute to modernisation efforts, including architectural improvements, component refactoring, and stack migrations that reduce technical debt and accelerate future delivery
• Review peers' pull requests with attention to UI consistency, accessibility, and frontend best practices
• Participate in production support and incident reviews, helping to strengthen the squad's operational resilience across its web domain

You'll be great for this role if…

• Strong experience with React, TypeScript, with a track record of delivering production-ready features end-to-end -not just isolated UI components
• Genuine full-stack capability: Experience defining API contracts, working with backend proxies, and owning integrations, not just consuming them; backend experience in Node, Kotlin, Java, or Golang is valued
• Solid understanding of frontend architecture, component design patterns, state management, and how frontend applications connect to backend services
• Experience writing and maintaining frontend tests (unit, integration, snapshot, end-to-end) and a genuine care for code quality and reliability
• Comfort navigating a complex, multi-stack codebase. React and TypeScript are core to this role, while our broader ecosystem also includes Node.js, Kotlin, Java, Go, Angular, AWS and Kafka. Prior experience with all of these is not required, but familiarity with most of them is a plus