# Use SpriteKit Objects within Scene Delegate Callbacks Follow threading guidelines to keep your SpriteKit app thread safe. ## Discussion SpriteKit is largely a single threaded game engine and as such the API provides developers with callbacks to implement your custom game logic. The primary callback for your game logic is [`update(_:for:)`](/documentation/SpriteKit/SKSceneDelegate/update(_:for:)). Other callbacks are illustrated in [`SKSceneDelegate`](/documentation/SpriteKit/SKSceneDelegate). Modifying SpriteKit objects outside of the scene delegate callbacks (such as in a background queue or anything else not running on the main thread) can result in concurrency related problems. Even dispatching work on the main thread asynchronously or at a later time is risky because the closure is likely to be done outside of the timeframe SpriteKit expects. If you’re experiencing a segmentation fault or other type of crash occurring deep within the SpriteKit framework, there’s a good chance your code is modifying a SpriteKit object outside of the scene delegate callbacks. > Note: > To check at runtime if a particular block of code is running on the main thread, inspect . --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)