XCUITest
XCUITest is Apple's official UI test automation framework for iOS apps, built directly into Xcode, letting developers write UI tests in Swift or Objective-C that run against the actual app using the platform's own accessibility APIs to locate and interact with elements.
Because XCUITest is Apple's own tool, it has first-class access to iOS internals and typically offers the most reliable, tightly integrated testing experience for pure iOS apps — tests run in a separate process from the app under test, closely mirroring how a real user interacts with it through the actual UI.
Its main tradeoff versus a cross-platform tool like Appium is scope: XCUITest is iOS-only, requires Swift or Objective-C, and only runs within the Apple development ecosystem — a natural fit for teams already fully invested in native iOS development, less so for teams wanting one shared test suite across iOS and Android.