what’s new in concurrency
Asked on 2025-07-03
•@wwdc251 search
In the WWDC 2025 sessions, several updates and improvements related to concurrency in Swift were introduced:
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Swift 6.2 Concurrency Enhancements: Swift 6.2 introduces changes to make concurrency more approachable. By default, code runs on the main actor, reducing the risk of data races. When you start using async functions, they run wherever they're called from, maintaining data safety. You can offload specific code to the background to run in parallel when ready to embrace concurrency for performance improvements. These changes are opt-in and can be enabled in Xcode Build Settings or a Swift package manifest file. What’s new in Swift
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Xcode 26 Debugging Improvements: Xcode 26 has improved its debugging capabilities for Swift concurrency. It now follows execution into asynchronous functions and displays task IDs in the debugger UI, making it easier to debug concurrency issues. What’s new in Xcode
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Concurrency in SwiftUI: SwiftUI leverages concurrency to improve app performance and responsiveness. Swift 6.2 introduces a new language mode that marks all types in a module with the
mainactorannotation implicitly, helping to avoid data race bugs. Explore concurrency in SwiftUI -
Approachable Concurrency Configuration: New app projects in Xcode 26 have features enabled by default that provide a more approachable path to introducing concurrency, such as the Main Actor by default mode. Code-along: Elevate an app with Swift concurrency
These updates aim to make concurrent programming in Swift safer and more accessible, allowing developers to write efficient and responsive applications.
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.
What’s new in Xcode
Discover the latest productivity and performance advancements in Xcode 26. Learn how to leverage large language models in your development workflow. Explore editing and debugging enhancements, improved performance and testing tools, and Swift Build - the open-source build system engine used by Xcode.
Code-along: Elevate an app with Swift concurrency
Learn how to optimize your app’s user experience with Swift concurrency as we update an existing sample app. We’ll start with a main-actor app, then gradually introduce asynchronous code as we need to. We’ll use tasks to optimize code running on the main actor, and discover how to parallelize code by offloading work to the background. We’ll explore what data-race safety provides, and work through interpreting and fixing data-race safety errors. Finally, we’ll show how you can make the most out of structured concurrency in the context of an app.