What’s the best way to use concurrency?
Asked on 06/12/2025
1 search
To effectively use concurrency in Swift, it's important to understand the concurrency model and how to apply it to your app. Here are some key points from the WWDC sessions on Swift concurrency:
-
Start with Single-Threaded Code: Begin by running all your code on the main thread. This is where your app receives UI-related events and can update the UI in response. Single-threaded code is easier to write and maintain (Embracing Swift concurrency).
-
Introduce Asynchronous Tasks: As your app grows, you may need to perform tasks that take a long time, such as network requests. Introduce asynchronous tasks to handle these operations without blocking the main thread (Embracing Swift concurrency).
-
Use Background Threads for Expensive Computation: Move expensive computations to background threads to keep the app responsive. Swift's concurrency model allows you to offload work to the background safely (Embracing Swift concurrency).
-
Leverage Actors and Nonisolated Code: Use actors to manage state that needs to be accessed concurrently. Nonisolated code can be used when you want to separate certain operations from the main actor (Embracing Swift concurrency).
-
Structured Concurrency: Use structured concurrency to manage the lifecycle of concurrent tasks. This helps in organizing and controlling asynchronous code (Code-along: Elevate an app with Swift concurrency).
-
Concurrency in SwiftUI: In SwiftUI, separate your UI code from non-UI code. Use state as a bridge to initiate async tasks and update the UI synchronously when tasks complete (Explore concurrency in SwiftUI).
By following these guidelines, you can effectively use concurrency to improve the performance and responsiveness of your app while avoiding common pitfalls like data races. For a deeper dive, consider watching the full sessions on Embracing Swift concurrency and Explore concurrency in SwiftUI.
Embracing Swift concurrency
Join us to learn the core Swift concurrency concepts. Concurrency helps you improve app responsiveness and performance, and Swift is designed to make asynchronous and concurrent code easier to write correctly. We’ll cover the steps you need to take an app through from single-threaded to concurrent. We’ll also help you determine how and when to make the best use of Swift concurrency features – whether it’s making your code more asynchronous, moving it to the background, or sharing data across concurrent tasks.
Explore concurrency in SwiftUI
Discover how SwiftUI leverages Swift concurrency to build safe and responsive apps. Explore how SwiftUI uses the main actor by default and offloads work to other actors. Learn how to interpret concurrency annotations and manage async tasks with SwiftUI’s event loop for smooth animations and UI updates. You’ll leave knowing how to avoid data races and write code fearlessly.
What’s new in Swift
Join us for an update on Swift. We’ll talk about workflow improvements that make you more productive, and new and modernized library APIs for fundamental programming tasks. We’ll show examples of Swift adoption throughout more layers of the software stack. Finally, we’ll explore new language features for both improving approachability of concurrency, and achieving peak performance when you need it.