Senior Kotlin Multiplatform Engineer (#4163)

About the Client: 

Our customer is a leading provider of onboard retail technology and mobile solutions for the travel and retail industries. The company designs and builds digital products that transform how airlines, trains, and retailers manage in-motion sales, inventory, and customer experiences. 

We are forming a dedicated Kotlin Multiplatform (KMP) team to build a new cross-platform mobile application from the ground up — one codebase, two native experiences: iOS and Android. You’ll join a small, highly skilled Scrum team that owns the full delivery pipeline — from architecture and development to testing, optimization, and release.

Responsibilities:

• End-to-end development of high-performance mobile applications for both iOS and Android using Kotlin Multiplatform (KMP).
• Design and implement shared business logic and platform-specific layers to ensure native user experience and optimal performance on each platform.
• Architect the application using Clean Architecture / MVVM / MVI, ensuring modularity, scalability, and maintainability.
• Experience with device-to-device communication protocols, especially Bluetooth/BLE.
• Develop rich, responsive UI layers using Jetpack Compose (Android) and SwiftUI (iOS) where necessary, leveraging Compose Multiplatform when appropriate.
• Integrate with backend APIs (REST / GraphQL), manage data synchronization, caching, and offline capabilities.
• Optimize app performance, memory usage, and responsiveness for both platforms.
• Implement comprehensive testing: unit, integration, and UI tests across platforms.
• Configure and maintain automated build, test, and release pipelines (CI/CD) for Android and iOS using tools like GitHub Actions, Bitrise, or Fastlane.
• Participate in code reviews, technical discussions, and agile ceremonies, ensuring continuous improvement and delivery excellence.
• Collaborate closely with backend engineers, designers, and QA to deliver polished, high-quality user experiences.

Must-Have Skills:

• 6+ years of experience in mobile application development.
• At least 2–3 years of proven hands-on experience delivering production apps using Kotlin Multiplatform (KMP) for both Android and iOS.
• Deep expertise in Kotlin, including coroutines, flows, multiplatform libraries, and shared data management.
• Experience with Bluetooth/BLE.
• Strong understanding of platform interoperability — bridging shared Kotlin code with Swift / SwiftUI on iOS and Jetpack Compose on Android.
• Experience developing and optimizing native UI components for each platform.
• Solid understanding of mobile performance optimization (memory management, rendering, startup time, network performance).
• Experience integrating RESTful APIs or GraphQL using Ktor Client or Retrofit with offline caching (SQLDelight / Room).
• Experience with CI/CD for mobile (Bitrise, GitHub Actions, Fastlane, Jenkins) and mobile release processes (Google Play, App Store).
• Strong Git workflow and experience with agile development environments (Scrum / Kanban).
• Fluent in English, both spoken and written.
• Clear communication skills: being able to explain complex technical issues to non-technical stakeholders.
• Experience in offline-first architectures, synchronization logic, and push notifications.

Would be a plus:

• Experience of mesh networking protocols and device-to-device communication.