Swift Testing is the modern framework for writing tests in Swift, built around expressive macros like @Test, #expect, and #require. It’s the successor to XCTest and the default testing framework for new projects in Xcode. Instead of dozens of assertion methods, you work with a single expressive macro that tells you exactly why a test …
Sendable and @Sendable closures explained with code examples
Sendable is a protocol in Swift that indicates a type is safe to share across concurrency domains like actors, tasks, and threads. When a type conforms to Sendable, the compiler verifies at compile time that passing it around can’t introduce data races. Together with the @Sendable attribute for closures, it’s one of the core building …
@MainActor in Swift explained with code examples
@MainActor is a global actor that performs its tasks on the main thread. You can use it to dispatch to the main thread by marking properties, methods, instances, or closures with the attribute. Instead of manually dispatching using DispatchQueue.main.async, you let the compiler enforce main thread execution for you. If you’re new to Actors in …
How to free up Xcode disk space safely with an AI Agent
Xcode disk space can grow rapidly without you noticing. Especially these days, with multiple agents turning multiple worktrees into silent disk space occupiers. Where I used to only focus on deleting old Simulators every now and then, I’m now also actively managing worktrees and derived data folders. There are great Mac apps and open-source projects …
How to Test iOS Apps in Different Time Zones on a Physical iPhone
Testing iOS Time Zones is a typical validation path that’s difficult without actually traveling yourself. You can apply all kinds of protocols and mock versions of your app, but having iOS act like it’s actually traveling between time zones is a real challenge. Ideally, you’d test apps like travel apps in such a way that …
User Diagnostics Reports: Solving app bugs faster with AI Agents
A user diagnostics report that helps you solve bugs and improve user support at the same time. I’ve been writing apps since 2009, and the Diagnostics repository is an outcome of all that experience. Used by major apps from companies like WeTransfer, it has proven its value time after time. I’ve seen consistent inefficiency at …
Defer in Swift explained with Code Examples
Although the defer keyword was already introduced in Swift 2.0, it’s still quite uncommon to use it in projects. Its usage can be hard to understand, but using it can improve your code a lot in some places. The most common use case seen around is opening and closing a context within a scope. Starting …
Memberwise Initializer in Swift explained with Code Examples
Memberwise initializers in Swift allow you to create struct instances without manually writing an initializer. The compiler examines the stored properties of your struct and automatically generates an initializer that accepts values for them. This feature is one of the reasons why structs are so lightweight to use in Swift. However, there are a few …
Swift 6.4: What’s New in Concurrency
Apple released Swift 6.4 during WWDC 2026, introducing a range of convenience improvements for both the general Swift language and the Concurrency APIs. While Swift is open-source, many of the changes might still have surprised you. At the same time, WWDC sessions do not cover all the new changes (if you have even had a …
SwiftUI Best Practices, straight from Apple’s Xcode 27 Agent Skill
Xcode 27 launched during WWDC 2026 and includes Apple’s SwiftUI Agent Skill for the first time. These skills work great for agentic development in Xcode, or when Using Xcode 27’s Agent Skills in Claude, Codex, and Cursor, any AI IDE. While we can use these skills and not look back, it’s far more interesting to …