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Kotlin Multiplatform Academy · Lesson

Suspend Functions as Swift async

Consume Kotlin coroutines from Swift concurrency.

Suspend Functions as Swift async is a free Kotlin Multiplatform Academy lesson on CoddyKit — lesson 2 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the Kotlin Multiplatform Academy learning path, one of 4 lessons in the course, and your progress syncs across the web and the CoddyKit app.

Suspend, Meet async

A Kotlin suspend function is exposed to Swift as an async method, so iOS can await it with native Swift concurrency.

suspend fun loadUser(): User

No Callbacks Needed

Older bridges forced completion handlers. Modern KMP maps suspend straight to async, so Swift code stays clean and linear.

Await It in Swift

From Swift you simply await the call inside an async context. The coroutine runs and resumes Swift when it finishes.

let user = try await repo.loadUser()

Errors Become throws

If the suspend function can fail, Swift sees it as a throwing async method, so you wrap the await in try and catch errors.

do { try await repo.loadUser() }
catch { print(error) }

Cancellation Carries Over

When Swift cancels its Task, that cancellation propagates into the Kotlin coroutine, stopping the shared work cleanly.

Run It in a Task

Call your async shared function from inside a Swift Task when you are not already in an async context, such as a button tap.

Task {
    let u = try await repo.loadUser()
}

Pick the Right Dispatcher

The coroutine runs on whatever dispatcher you set in shared code, so heavy work stays off the iOS main thread by default.

Returning Values

Whatever the suspend function returns becomes the result of the Swift await, mapped through the usual Kotlin-to-Obj-C rules.

Unit Means Void

A suspend function returning Unit shows up in Swift as an async method that simply returns nothing, just like void.

Generated by SKIE

Plain KMP gives you basic async support, but tools like SKIE generate even smoother Swift signatures for these suspend calls.

Linear and Readable

The big win is readability: shared async logic reads top-to-bottom in Swift, with no nested callbacks or completion pyramids.

Quick Check

Let us check how a suspend function feels from Swift.

Recap

Kotlin suspend becomes Swift async: await it in a Task, catch thrown errors, and cancellation flows both ways. Clean concurrency. ✅

Frequently asked questions

Is the “Suspend Functions as Swift async” lesson free?

Yes — the full text of “Suspend Functions as Swift async” is free to read here on the web, and the Kotlin Multiplatform Academy course includes 4 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the Kotlin Multiplatform Academy course, upgrade to CoddyKit PRO.

What will I learn in “Suspend Functions as Swift async”?

Consume Kotlin coroutines from Swift concurrency. You practise Kotlin Multiplatform Academy with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.

Do I need any experience to start Kotlin Multiplatform Academy?

No prior experience is required. Kotlin Multiplatform Academy on CoddyKit is structured for beginners through advanced learners; this is — lesson 2 of 4, so you can start here or from the beginning and move at your own pace.

How long does the “Suspend Functions as Swift async” lesson take?

Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.

Can I write and run code in this Kotlin Multiplatform Academy lesson?

Yes. Every Kotlin Multiplatform Academy lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.

All lessons in this course

  1. How Kotlin Maps to Objective-C
  2. Suspend Functions as Swift async
  3. Collect Flows from Swift
  4. @ObjCName & Swift-Friendly APIs
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