@MainActor is a Swift attribute that ensures code runs on the main thread/main actor. It’s used to guarantee UI updates and other main-thread-only operations execute safely.

Key uses:

• Classes/structs that update UI
• Properties/methods that must run on main thread
• Preventing data races in concurrent code
• SwiftUI view models and UI-related code

Example:
@MainActor
class ViewModel: ObservableObject {
@Published var data: String = “”

  func updateUI() {
      // Always runs on main thread
      data = "Updated"
  }

}