Senior iOS Engineer

Senior iOS Engineer (Swift) – SumUp Pay

Location: London, United Kingdom Team: Consumer

Team description

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 maint