Senior Frontend Engineer – Sell Online

Meyandy LLC; Köln; Vor Ort; EUR 75.000 - 110.000; Vollzeit

Benefits dieser Stelle

Open Cologne office

Virtual Stock Option programme

€2000 annual L&D budget

28 days paid leave

Subsidised mobility

Urban Sports Club access

Corporate pension plan

Employee discounts

1-month sabbatical after 3 years

Referral bonus

Zusammenfassung

SumUp is seeking a Senior Frontend Engineer – Sell Online, based in Cologne. You’ll own frontend features for payment links, gift cards, and checkout, contributing to integration products and SDKs used across SumUp. Join a small, cross-functional team and shape product evolution from day one.

The role requires 5+ years in TypeScript/JavaScript with React/Next.js, SSR, and strong testing skills. You’ll work in an agile environment, contribute to performance and accessibility improvements, and

Qualifikationen

• 5+ years of TypeScript/JavaScript experience.
• Production-grade React/Next.js with SSR.
• Experience writing unit/integration/e2e tests (Jest, Vitest, RTL).
• Familiar with CI/CD and Agile processes (Scrum/Kanban).
• Knowledge of UI libraries (Radix, shadcn) and accessibility best practices.
• Strong product mindset focused on merchant value.

Aufgaben

• Build and maintain frontend features across payment links, gift cards, and online checkout.
• Develop and maintain integration products and SDKs used by internal and external teams.
• Engage in technical planning, design reviews, and sprint ceremonies.
• Reduce tech debt and improve performance, observability, and accessibility.
• Monitor live services and respond to issues to ensure reliability.

Kenntnisse

TypeScript

JavaScript

React

Next.js

SSR

Testing

CI/CD

Agile

Accessibility

Product mindset

Tools

Jest

Vitest

React Testing Library

Radix

shadcn

Next.js

Jobbeschreibung

About the team

You'll join the Sell Online Tribe, the group shaping how merchants bring their businesses to life online. We design and build tools that help millions of entrepreneurs, from barbers to bakers, sell their products and services anywhere.
You'll be working on some of SumUp's biggest merchant-facing online products as part of the Bifrost team, contributing to growing and scaling critical products like Payment Links and Gift Cards, while also working on integration products that provide essential features used across many other SumUp products. They're high-traffic, high-responsibility products that other SumUp teams depend on too.
You'll join a small, cross-functional team and take on genuine ownership of the frontend - not just executing tickets, but shaping how the products evolve. With new features to ship and integration products to keep secure and current, there's real, meaningful work to get stuck into from day one.

What you'll do

• Build and maintain frontend features across payment links, gift cards, and online checkout products, writing clean, testable, and maintainable code
• Contribute to the development and upkeep of our integration products and SDKs, used by both internal teams and external partners
• Take part in technical planning, design reviews, and sprint ceremonies - bringing your perspective on estimations, trade-offs, and improvements
• Help reduce tech debt and improve application performance, observability, and accessibility as a foundation for future delivery
• Monitor live services and respond to issues, providing redundancy for customer support requests reaching the team

You'll be great for this role if…

• You have 5+ years of experience in TypeScript and JavaScript, with hands‑on experience building production‑grade React and Next.js applications (including SSR and app router patterns)
• You have experience writing unit, integration, and end‑to‑end tests using tools like Jest, Vitest, or React Testing Library
• You're comfortable working within CI/CD workflows and collaborating in agile environments (Scrum or Kanban)
• You have experience with UI libraries such as Radix or shadcn, and a solid understanding of accessibility and UX best practices
• You have a product mindset - someone who cares about the value delivered to merchants, not just the code written to get there, and who can work autonomously to drive complex features end‑to‑end

Why you should join SumUp

• Opportunity to work in a truly global, multicultural team from our open, vibrant Cologne office, located in the heart of the city. This involves an office‑first setup
• 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 €2000 for your individual development, which can be used to attend conferences and/or advance your career through further education
• Generous time off: enjoy 28 days of paid leave plus public holidays and special leave days
• Commute made easy: subsidised mobility options like discounted transport tickets or bike leasing
• Stay active: access to fitness via Urban Sports Club, mostly covered by SumUp
• Financial health: a corporate pension scheme with SumUp contributing an extra 20% on top of your contribution
• Employee perks: get discounts across products and services via our Corporate Benefits platform
• Break4me: 1-month sabbatical after 3 years of service
• Referral Bonus: earn additional rewards by referring talented individuals to join the SumUp team

About SumUp

Be empowered to do more that matters.

At … Senior Frontend Engineer – Sell Online – sumup, Cologne.