The Kotlin Swift boundary

on YouTube ↗41m

" summary

Kotlin/Native compiles to Objective-C-compatible bytecode but idiomatic Swift often breaks: default parameters lost through the Obj‑C layer, generics erased at protocol boundaries, and reference‑counting plus the freeze API create surprising concurrency constraints. Practical fixes include adapter classes, JSON ↔ NSDictionary bridges using kotlinx.serialization, a flow-to-publisher adapter to expose Kotlin Flows as Combine publishers, and packaging via frameworks/CocoaPods or SPM wrappers; a new memory model lands experimentally in Kotlin 1.6 M1.

AI-written summary · about

" chapters (16)

1. 0:00Kotlin Swift boundary intro
2. 1:25Kotlin multi-platform overview
3. 4:17Shared vs platform Kotlin code
4. 7:48Kotlin multi-platform model
5. 8:08Bridging Kotlin to Swift
6. 10:15Default params in Swift interop
7. 12:46Generics challenges in interop
8. 15:37Protocols and generics limits
9. 16:40Kotlin memory model for iOS
10. 19:08Kotlin data vs Swift structs
11. 21:15Kotlin sealed vs Swift enums
12. 22:59Async in Kotlin and Swift
13. 26:10Shared logic case study
14. 29:02Key lessons from interop
15. 31:53Future of Kotlin multi-platform
16. 32:55Q&A on interop

" related talks

• 49mEffective Kotlin-Swift InteroperabilityJohn Rodriguez · KotlinConf 2019
• 45mSDK Design and Publishing For Kotlin Multiplatform MobileKevin Galligan · droidcon Berlin 2022
• 36mWriting Kotlin Multiplatform libraries that your iOS teammates are gonna loveAndré Oriani · Droidcon London 2023
• 52mKEYNOTE: Kotlin/Native – Embracing existing ecosystemsHadi Hariri · ACCU 2018
• 33mKotlin Multiplatform Alchemy: Making Gold out of Your Swift InteropPamela Hill · AndroidMakers by droidcon 2025
• 21mKotlin For Swift DevelopersEllen Shapiro · try! Swift Tokyo 2018
• 37mKotlin and Compose Multiplatform patterns for iOS interopJohn O'Reilly · droidcon London 2025
• 39mDependencies and Kotlin/NativeTadeas Kriz · droidcon Berlin 2025