kmp-ios-integration

KMP → iOS Integration

Overview

The KMP shared module compiles to a native Apple framework that the iOS app links against. Two things must be right: (1) export the framework from Gradle, and (2) bridge Kotlin suspend/Flow into idiomatic Swift async/AsyncSequence.

When to use

• Wiring an iOS app to consume a KMP shared module
• binaries.framework / XCFramework export configuration
• Choosing CocoaPods vs Swift Package Manager vs a direct framework
• Kotlin suspend/Flow not callable nicely from Swift → SKIE / NativeCoroutines
• Errors like "framework not found", missing symbols, "embedAndSign", or a crash on launch from a non-embedded framework

Framework export (shared/build.gradle.kts)

kotlin {
    listOf(iosArm64(), iosSimulatorArm64()).forEach { target ->
        target.binaries.framework {
            baseName = "Shared"   // becomes `import Shared` in Swift
            isStatic = true       // static linking — simplest for an app target
        }
    }
}

Build an XCFramework for binary distribution: ./gradlew :shared:assembleSharedXCFramework

Distribution options

Option	When	Setup
Direct framework + embedAndSign	Single repo; the app build also builds shared	Run embedAndSignAppleFrameworkForXcode in a Run Script build phase; set the framework to Embed & Sign
CocoaPods (kotlin-cocoapods)	You already use a Pods workflow	cocoapods { framework { baseName = "Shared" } } block, then pod install
SPM / KMMBridge	Ship a prebuilt binary to a separate iOS repo	XCFramework + Package.swift (KMMBridge automates publishing)

Exposing suspend/Flow to Swift — SKIE (recommended)

Plain Kotlin/Native exposes suspend as a completion-handler function and Flow as an opaque type. SKIE rewrites the generated Swift API so suspend becomes async and Flow/StateFlow become AsyncSequence:

// shared/build.gradle.kts
plugins { id("co.touchlab.skie") version "<latest>" }