Senior iOS Developer (Mobile Commerce)

About the role

We are looking for a Senior iOS Developer to build and improve a high-traffic retail shopping app. The app runs on the POQ app-commerce platform, with SAP Commerce Cloud as the e-commerce backend.

You will own key parts of the shopping journey, from product browsing and product detail pages to basket and checkout. The focus is a fast, stable app that handles large product catalogues, many images and peak trading traffic without slowing down or crashing.

What you'll do

• Build and maintain features in Swift across the shopping journey: product listing, product detail pages (PDP), search, basket, checkout and order history.
• Apply MVVM and clean architecture so screens stay testable, reusable and easy to change.
• Build checkout flows that handle complex orders, including splitting one order into several shipments based on store and warehouse stock.
• Design and maintain a clean networking layer for REST APIs, with typed models, error handling, retries and authentication.
• Use caching (NSCache, URLCache, on-disk storage) to keep PDP and catalogue screens fast.
• Optimise image loading and memory use for image-heavy product screens.
• Support offline use, persist product and cart data, and keep the cart in sync across devices and sessions.
• Find and fix crashes, memory leaks and slow screens using Instruments, Xcode Memory Graph and Firebase Crashlytics.
• Keep the UI smooth using Swift concurrency (async/await, actors), GCD and OperationQueue where each fits best.
• Own release delivery: certificates, provisioning profiles, TestFlight builds, App Store submission and CI/CD pipelines.
• Work with backend, design, QA and product teams on POQ configuration and SAP Commerce APIs.

What you'll bring

• Swift and iOS SDK: strong Swift, UIKit and SwiftUI, with a solid grasp of memory management (ARC, retain cycles, weak/unowned).
• Architecture: MVVM and MVC, and when to use each; clean architecture, coordinators, dependency injection and protocol-oriented design.
• Networking: URLSession, Codable, a modular API layer with request builders, error mapping, token refresh and retry logic.
• Concurrency: async/await, Task, actors and MainActor; GCD and OperationQueue for older code and dependent tasks.
• Caching and persistence: NSCache, URLCache and disk caching; Core Data, SwiftData or Realm; offline-first data and cart sync.
• Image performance: downsampling, prefetching, cell reuse and libraries such as Kingfisher or SDWebImage.
• Debugging and monitoring: Instruments (Time Profiler, Allocations, Leaks), Xcode Memory Graph and Firebase Crashlytics, including dSYM symbolication.
• Release management: certificates, App IDs, provisioning profiles, signing, TestFlight and App Store Connect review.
• E-commerce experience: at least one shipped retail or e-commerce app covering PDP, basket and checkout.
• Engineering practice: Git, unit and UI testing (XCTest), code review, and CI/CD with Xcode Cloud, Fastlane, Bitrise or GitHub Actions.

Nice to have

• Experience with the POQ app-commerce platform or a similar mobile commerce SDK (Shopify Mobile Buy SDK, Salesforce Commerce Cloud, commercetools).
• Working with SAP Commerce (OCC) APIs from a mobile app.
• Apple Pay, payment SDKs (Adyen, Stripe, Klarna) and secure storage with Keychain.
• Push notifications, deep links and universal links, and analytics tools (Firebase Analytics, Adobe, Amplitude).
• Combine, Swift Package Manager and modular app design.
• Accessibility (VoiceOver, Dynamic Type) and localisation for multiple markets.
• Some Android or Kotlin exposure.

Experience and qualifications

• 5–9 years in mobile development, including 4+ years building native iOS apps in Swift.
• At least 2 apps released to the App Store, ideally including a retail or e-commerce app with high daily traffic.
• Proven record of improving app stability (crash-free rate) and performance in production.
• Bachelor's degree in Computer Science or equivalent practical experience.
• Clear written and spoken English, and comfortable working with designers, backend engineers and product owners.
• Calm ownership of production issues and release deadlines, especially during peak trading.