Senior iOS Engineer in City of Westminster

Location: London, United Kingdom

Team: Consumer

The Consumer team builds and maintains SumUp Pay — a regulated consumer banking app spanning payments, card management, savings, and open banking, used by hundreds of thousands of customers every day. We're a cross-functional squad of engineers, product managers, and designers working at pace on a product that genuinely matters to the people who rely on it. Right now, we're growing our iOS function to match the ambition of our product roadmap — and this role sits at the heart of that.

As an iOS Engineer, you'll own meaningful parts of the SumUp Pay experience end-to-end, from onboarding and KYC flows through to savings features and in-app messaging. With a lean iOS team and a growing product surface, there's real scope to shape how we build — not just what we build.

What you'll do

• Design, build, and ship iOS features across SumUp Pay — including KYC and card activation flows, savings, open banking consent, and payment experiences.
• Take ownership of performance monitoring, crash reporting, and app stability, proactively resolving issues before they reach customers.
• Contribute to the evolution of our iOS architecture — including modularisation, dependency management, and scalability as the product grows.
• Partner with the CRM Manager to implement in-app messaging (modals and banners) via Iterable, ensuring correct event instrumentation and display logic on iOS.
• Write clean, testable Swift code and contribute actively to code reviews, CI/CD pipeline health, and a culture of quality across the team.

You'll be great for this role if…

• Strong proficiency in Swift and the iOS framework, with a track record of shipping consumer-facing features in a product environment.
• Experience integrating RESTful APIs and collaborating closely with backend engineers on API design and contracts.
• Solid understanding of iOS architecture patterns, modularisation, and writing maintainable, well-tested code.
• Comfort working in a regulated or fintech environment, with an appreciation for the security, compliance, and data privacy considerations that come with it.
• A product-oriented mindset — someone who thinks about the user journey, not just the implementation, and brings both craft and pragmatism to technical decisions.

Why you should join SumUp

• Opportunity to work with a truly global, multicultural team from our central Covent Garden location, wrapped in historic charm and modern flair. 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.
• Generous time off: enjoy 28 days of paid leave, plus bank holidays and special leaves.
• A dedicated annual L&D budget for attending conferences and/or advancing your career through further education.
• Health matters: private health insurance, including optical and dental.
• Life made easier: salary-sacrifice commuter benefits via Gogeta.
• Financial security: retirement scheme (SumUp matches 7% when you contribute 5%).
• Peace of mind: life insurance from MetLife for 2× your salary.
• 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 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.

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.