IOS Engineer - Design System

About the team

As an iOS Engineer on the Design System team, you'll translate Sum Up's design language into a reusable, easy-to-use library of UI components and experience patterns — empowering product teams to build cohesive, accessible user experiences  Design System team works hand-in-hand with the Mobile Platform team to set standards and provide guidance across all product teams  we expand our ecosystem of merchant and consumer-facing products, this role offers a rare opportunity to shape the foundation that helps developers build faster and ship higher-quality experiences to millions of users worldwide.

• Shape the core experience for both users and developers interacting with Sum Up's iOS ecosystem
• Collaborate closely with product and design teams to build components that are maintainable, consistent, and beautiful
• Embed accessibility best practices into every component — from content descriptions and touch target sizing to color contrast and dynamic type
• Provide hands-on technical guidance to product teams to deliver on company priorities, including the upcoming brand refresh
• Review code contributions, enforce design system conventions, and mentor engineers on best practices for reusable UI development
• Lead the migration of legacy UIKit-based components to SwiftUI while maintaining system stability
• Proactively identify and address technical debt to uphold a high bar for engineering excellence and codebase health

• Bring 3+ years of professional iOS development experience, ideally on large-scale or consumer-facing applications
• Are fluent in Swift, with deep hands-on knowledge of both SwiftUI and UIKit — and a clear view on when and how to use each
• Bring experience building or contributing to a design system, component library, or shared UI framework, and understand what it takes to make components truly reusable and scalable
• Take pride in crafting accessible user experiences — you know your way around Voice Over, dynamic type, color contrast, and touch target standards, and treat accessibility as a first-class concern, not an afterthought
• Bring a strong grasp of testing best practices for UI components, including unit tests, snapshot tests, and UI automation
• Are comfortable reviewing code and mentoring peers — you enjoy sharing knowledge, giving constructive feedback, and raising the bar for the whole team
• Are self-motivated and structured in your working style — you manage your own priorities, communicate clearly in English, and thrive in a cross-functional, collaborative environment
• Stay genuinely curious about the iOS ecosystem — you follow Apple's releases closely, experiment with new APIs, and are excited to bring fresh ideas back to the team

• Opportunity to work with Sum Uppers globally on large-scale fintech products used by millions of businesses worldwide, from our Berlin office. 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 Sum Up's future success
• A dedicated annual L&D budget of €2000 for your individual development, which you can be used to attend conferences and/or advancing your career through further education
• A corporate pension scheme where we match up to 20% of your contributions
• Generous time off: enjoy 28 days of paid leave plus public holidays and special leave days
• Numerous other benefits such as Urban Sports Club subsidy, Kita placement assistance, subsidised office lunches
• Break4me: 1-month sabbatical after 3 years of service
• Referral Bonus: earn additional rewards by referring talented individuals to join the Sum Up team

We believe in the everyday hero. Small business owners are at the heart of all we do, so we're creating tools that help them run their businesses. With a founder's mentality and a 'team-first' attitude, our diverse…

iOS Engineer - Design System — Sum Up, Berlin.