Senior Software Engineer (iOS)

We’re Kingfisher, a team made up of over 74,000 passionate people who bring Kingfisher - and all our other brands: Castorama, B&Q, Screwfix, Brico Dépôt and Koçtaş - to life. That’s right, we’re big, but we have ambitions to become even bigger and even better. We want to become the leading home improvement company and grow the largest community of home improvers in the world. And that’s where you come in.

At Kingfisher, our customers come from all walks of life, and so do we. We want to ensure that all colleagues, future colleagues, and applicants to Kingfisher are treated equally regardless of age, gender, marital or civil partnership status, colour, ethnic or national origin, culture, religious belief, philosophical belief, political opinion, disability, gender identity, gender expression or sexual orientation.

We are open to flexible and agile working. Therefore, we offer colleagues a blend of working from home and our office, located in Kraków. Talk to us about how we can best support you!

At Kingfisher, we value the perspectives that any new team members bring, and we want to hear from you. We encourage you to apply for one of our roles, even if you do not feel you meet 100% of the requirements.

In return, we offer an inclusive environment, where what you can achieve is limited only by your imagination! We encourage new ideas, actively support experimentation, and strive to build an environment where everyone can be their best self. Interested? Great, apply now and help us to Power the Possible.

We offer a competitive benefit package and plenty of opportunities to stretch and grow your career:

• 20,000 - 28,000 PLN gross per month on an employment contract
• Private medical healthcare at LUXMED (including dentalcare) for you and your family
• Medicover sports card (Fit&More package)
• Life insurance financed by the employer
• 30-minute lunch break included in the 8-hour working day
• Work in a highly professional and stimulating atmosphere
• Training & Buddy programme that will allow you to quickly adapt to your new role
• Wellbeing programme for employees
• Co-financing of monthly tickets for the public transport in Krakow
• Comfortable working environment in the office and the possibility of home office
• Language courses, accounting courses, access to LinkedIn Learning and the possibility of co-financing studies and certification
• Employee referral programme

What's the job

About the role

We're going through an exciting period of change on our mobile platform, and we're looking for a motivated Senior iOS Engineer to join our Engineering team.

Our app (Castorama Poland, part of Kingfisher) is built as a Kotlin Multiplatform (KMP) product: domain, data, networking and persistence logic is written once in shared Kotlin and consumed by both our native iOS (Swift/SwiftUI) and Android apps through a shared `KingfisherFoundation`framework.

We're deliberately moving more logic into that shared Kotlin layer over time, with iOS as a first-class consumer.

We're looking for someone who is genuinely excited by this direction - an iOS expert who also wants to work in Kotlin Multiplatform: extending the shared Kotlin layer, shaping its Swift-facing API, and helping drive the app further toward shared code. This is a role for an engineer who sees KMP as an opportunity, not a threat, and who will champion the shared-code direction rather than resist it.

You'll design, build and maintain high-quality iOS applications while collaborating closely with Android engineers, backend engineers, product managers and designers, and you'll help set the technical direction for iOS as our KMP adoption deepens. You'll work with a modern, opinionated stack and follow best practices in mobile architecture, performance and security.

If you want to step out of your comfort zone, work across the Swift/Kotlin boundary, and make a real impact on how a large-scale retail app is built; this is the job for you.

Responsibilities

• Lead the design, development and maintenance of scalable, high-performance iOS applications using Swift, SwiftUI and Xcode, following The Composable Architecture (TCA) and a modular Swift Package Manager codebase.
• Work hands-on in our Kotlin Multiplatform shared layer - consuming and extending shared Kotlin UseCases, repositories and models exposed to iOS through the KingfisherFoundation framework and helping grow the amount of logic that lives in shared code.
• Collaborate with Android and backend engineers to shape the Swift-facing API of the shared KMP layer so it serves both platforms cleanly and help define our long-term multiplatform mobile strategy.
• Integrate and maintain our GraphQL (Apollo Kotlin) and REST (Ktor) data layer - including the iOS URLSession/Ktor bridge and normalized caching - and third-party SDKs and platforms.
• Champion mobile security (OAuth2 / PKCE, CIAM, Keychain, certificate pinning, jailbreak detection, F5 API protection), accessibility, performance optimisation and overall app quality across the development lifecycle.
• Lead code reviews, mentoring, refactoring initiatives and complex troubleshooting across the Swift Kotlin boundary to keep the codebase high-quality and sustainable.
• Support and improve our CI/CD and release pipelines (Bitrise, fastlane, Danger, match, TestFlight) and engineering workflows to increase delivery efficiency and stability.
• Drive engineering best practices - clean modular architecture, robust unit and UI testing (XCTest with TCA's TestStore, XCUITest) and maintainable code.
• Stay current with emerging iOS and Kotlin Multiplatform technologies, proactively introducing improvements and sharing knowledge across the iOS and Android teams.
• Mentor junior and mid-level developers, and contribute to technical decision-making, architectural planning and long-term mobile strategy within the engineering organisation.

What you'll bring

• Expert knowledge of Swift, SwiftUI and the Xcode ecosystem (UIKit familiarity for interop is useful, but our UI is SwiftUI-first).
• Genuine enthusiasm for Kotlin Multiplatform and working in shared Kotlin - you want the app to move toward more shared code and you're keen to contribute to the Kotlin layer yourself, not just consume it. (Direct Kotlin/KMP experience is a strong advantage; a real willingness to learn it fast is essential.)
• Strong command of modern, state-driven app architecture - we use The Composable Architecture (TCA); experience with TCA, MVVM, MVI or similar unidirectional patterns is valued.
• Solid experience with modular codebases and dependency management using Swift Package Manager, and with Swift Concurrency (async/await).
• Proven experience integrating GraphQL and REST APIs, SDKs and third-party platforms.
• Strong knowledge of mobile security, performance optimisation and accessibility best practices.
• Ability to lead technical discussions, mentor developers and drive engineering best practices.
• Excellent problem-solving skills, attention to detail and strong collaboration in cross-functional teams.
• Excellent command of English (written and spoken).

Nice to have

• Hands-on Kotlin / Kotlin Multiplatform experience (Apollo Kotlin, Ktor, SQLDelight, Koin).
• Experience with CI/CD for mobile (Bitrise, fastlane, Danger, match) and TestFlight release management.
• Experience with cloud-backed mobile backends and observability / analytics tooling (GraphQL gateway on GCP/k8s, Firebase, Datadog RUM, Tealium), feature-flagging (Optimizely, Firebase Remote Config) and push (Airship).
• Experience with OAuth2 / PKCE and CIAM identity flows.