Create apps that allow players to interact with each other using GameKit.

GameKit Documentation

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Game Center Authentication Crashing - Unity 6, Gamekit 3.0.2
When testing my development build for gamecenter authentication, the game crashes. I've breadcrumbed it to the "await GKLocalPlayer.Authenticate();" call. Can't find any documentation on this issue and have been looking through the forums! I've already done all of the usual stuff like verifying bundle identifiers match, ensuring game center is enabled for the app, setting up app store connect, using a sandbox account, etc... Please point me to some resources if you know any. Any help is appreciated, I'm starting to lose hope here!
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Apr ’25
Testing Achievements - Apple Documentation out of Date
New to achievements. I added them in App Store Connect and want to test them. Apple Documentation says this: "Before you begin testing your GameKit configuration, you need to enable Debug Mode. In Xcode, choose Product > Scheme > Edit Scheme. From the Run configuration, select Options and toggle Enable Debug Mode. To begin testing your achievement configuration, open the game Progress Manager. In Xcode, choose Debug > GameKit > Manage Game Progress." Sounds easy enough, but there is no "GameKit" under Debug in Xcode 16.2.
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May ’25
authenticateHandler events not being received on iOS 18
I work on a team that provides an SDK for another game to handle various tasks like authentication. They are experiencing a case where devices using iOS 17 are failing to authenticate with GameCenter, receiving the message "The requested operation could not be completed because local player has not been authenticated." We imagine this is because they still have some setup to finish regarding GameCenter itself, and we're working with them to take care of that. However, on iOS 18, their app ends up waiting indefinitely for GameCenter authentication messages that it never receives. That's where we're puzzled. We expect them to have the same outcome regardless of OS version. We initiate GameCenter authentication by setting an authenticateHandler after some initial application setup. The handler has code to account for UI, errors, and successful authentication. On iOS 17, it's clear that it's getting called as expected because they receive an indication that the player isn't authenticated. But on iOS 18, it looks like the same handler code on iOS 18 isn't being called at all. Are there differences in how iOS 18 interacts with the authenticationHandler that we somehow aren't accounting for? Or is there potentially something else that we're doing incorrectly that is manifesting only on iOS 18? Here's a simplified version of our login function code (in Obj-C++). There is no OS-specific code, and the job that owns this function does stay in scope until after authentication is complete. void beginLogin() { // Snip: Check if the user is already logged in. // Snip: Prevent multiple concurrent calls to this function. auto authenticateHandler = ^(UIViewController* gcViewController, NSError* error) { if (gcViewController != nil) { // Snip: Display the UI } else if (error != nil) { // Snip: Handle the error. } else { if ([[GKLocalPlayer localPlayer] isAuthenticated]) { // Snip: Handle successful authentication. } else { // Snip: Handle other case. } } }; [[GKLocalPlayer localPlayer] setAuthenticateHandler: authenticateHandler]; }
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May ’25
Blurry Game Center Achievement Images?
Hey all — I’ve been building out my first set of Game Center Achievements for a game I’m working on, and I’ve run into something odd with the image quality. The specs say to upload icons at 512x512 or 1024x1024@2x. I’ve been uploading 1024x1024 PNGs (without explicitly naming them “@2x” since there’s only one upload slot), assuming that Game Center would just handle the scaling automatically — kind of like how a lot of things are getting more streamlined across platforms lately. But in testing, the icons are showing up a bit blurry, especially in the Game Center interface. It’s not horrible, but it’s definitely softer than I expected — more like low-res than Retina. All my test devices (outside the Simulator) are running iOS 26, so I’m also wondering if this might be a beta-related display bug? Has anyone else run into this? Curious if I’m missing a best practice here, or if I really do need to ensure I’m uploading it with the @2x suffix, or maybe something else entirely? Thanks!
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Jul ’25
GameKit Achievements, Leaderboards and Challenges not showing on iOS 26 beta 4 in the Game Center UI (opened from GKAccessPoint)
On an iPad running iPadOS 26 beta 4, when tapping the Game Center Access Point, the overlay doesn’t show the configured achievements, leaderboards or challenges. I should specify this is an in-development app and the achievements and leaderboards are in the “Not Live” state, however they show on other devices running iOS 18 in the Access Point UI. Anyone else having this issue? If so, how should I test achievements and leaderboards while iOS 26 beta is out? The UI looks like this on iPadOS 26:
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Aug ’25
App not showing in Game Center “All Activity” after release
Hello — I shipped an App Store build that signs in to Game Center using the Apple Unity Plugins (GameKit). The login banner appears, but my app still doesn’t show up in Game Center’s “All activity” (You started playing XXX 2d ago) What I’ve done Call await GKLocalPlayer.Authenticate(); “Game Center” is enabled for the current version in App Store Connect Confirmed: other App Store games do appear under “All Activity” on the same device/account Timeline: This is the first version that enables Game Center (not the app’s first release), and it has been about 2 hours since this build went live. Questions Is authentication alone sufficient for “Recently Played,” or is at least one Game Center component (leaderboards, achievements, activities, multiplayer) required? Is there a typical propagation delay before “Recently Played” starts showing a newly enabled app/version? Is there anything else I should configure in App Store Connect or entitlements to make “Recently Played” visible? Thanks for any help.
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575
Aug ’25
Unity GameKit plugin beta GameKit Activity UnsupportedOperationForOSVersion
I’m running into unexpected problems with the Unity GameKit plugin setup with the new Activities. I didn’t see anyone else mentioning these issues, so my guess is that it’s a problem with my setup. The authentication (GKLocalPlayer.Authenticate()) works as expected, but any call to the new GameActivity functionality (e.g. GKGameActivityDefinition.LoadGameActivityDefinitions() or GKGameActivity.WantsToPlay) gives me an exception with a 'UnsupportedOperationForOSVersion' reason despite it running on an iOS 18.6.1 device. I’m using a completely empty Unity 2022.3.62f1 project that only contains the official authentication example, followed by an event handler for activities from another example and the Unity core and gamekit plugins. The setup: macOS 15.6 Xcode 26 beta 6 (also tried with 5) Physical iPhone device running iOS 18.6.1 Unity 2022.3.62f1, which satisfies the requirements Unity plugin, Xcode setup, and build steps: I Followed the official beta branch build steps for Unity plugins with python3 build.py -m iOS iPhoneSimulator macOS -p Core GameKit which ran through after a slight modification for the macOS target that somehow contained an unknown team reference for the GameKitWrapper project, which I changed to not reference a team and use ‘sign to run locally’, as was the case for the other packages. As far as I understood the macOS version is not strictly necessary either way just for running it on a local iOS device(?) I Imported these as tarball packages into the empty Unity 2022.3.62f1 project as per the official instructions, which seems to work as expected Added a single script with the mentioned example code added in a MonoBehavior.Start Building in Unity works as expected as well, creating the Xcode project The Unity-iPhone target has the GameKit framework linked (’do not embed’) and the GameCenter capability was added automatically as expected The GameKit framework seems to not be added to the UnityFramework target, but I don’t think this is necessary? Quickly testing this with the GameKit framework added there as well didn’t make a difference The linked GameKit framework is indeed the expected Xcode 26 beta version I can then build and run this on the physical iPhone iOS 18.6.1 device, where I get an ‘UnsupportedOperationForOSVersion’ as soon as I try to subscribe to deeplinking events (GKGameActivity.WantsToPlay) or use other GameKit Activity functionality from the official examples: // log showing that it's actually running on iOS 18.6: [Apple.Core Plug-In Runtime] Availability Runtime Environment: iOS 18.6 Apple.Core.Availability:OnApplicationStart() // and the exception I get: GameKitException: Code=-7 Domain=GKErrorDomain Description=The operation couldn’t be completed. (GKErrorDomain error -7.) (UnsupportedOperationForOSVersion) at Apple.GameKit.DefaultNSErrorHandler.ThrowNSError (System.IntPtr nsErrorPtr) [0x00000] in <00000000000000000000000000000000>:0 Rethrow as TypeInitializationException: The type initializer for 'Apple.GameKit.GKGameActivity' threw an exception. I unfortunately didn’t find any clues as to why this happens and how to resolve it on this forum or otherwise. Changing the minimum iOS version - up to 18.6 from the previously used (Unity export default) 12.0 for any and all targets - did not yield a different result I'd rather not update the phone to use the iOS 26 beta, though as far as I understood this is not necessary Any pointers to what I might be missing or doing wrong are greatly appreciated! Thank you very much in advance!
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Aug ’25
iOS 26 Games app: Wired Switch Pro controllers (and GameSir X5 Lite) not working correctly
Hi, Since iOS 26 introduced the new Games app, I’ve noticed a problem when using a Nintendo Switch Pro Controller in wired USB-C mode, and also with third-party controllers that emulate it (like the GameSir X5 Lite). In the Games app interface, only the L/R buttons respond, but the D-Pad and analog sticks don’t work at all. Once inside actual games, the controller works fine — the issue only affects the Games app UI. What I’ve tested so far: Xbox / PlayStation controllers → work fine in both wired and Bluetooth, including inside the Games app. Switch Pro Controller (Bluetooth) → works fine, including in the Games app. Switch Pro Controller (wired) → same issue as the X5 Lite, D-Pad and sticks don’t work in the Games app. This makes it hard to use the new Games app launcher with these controllers, even though they work perfectly once a game is launched. My question: is this an iOS bug (Apple needs to add proper support for wired Switch Pro controllers in the Games app), or something that Nintendo / GameSir would need to address? Thanks in advance to anyone who can confirm this or provide more info.
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Sep ’25
Game Center SignIn alert appears on macOS 26 (Tahoe) without capability or entitlement
Hello, On macOS 26 (Tahoe), when building a OSX app that includes GameKit code, calling GKLocalPlayer.local.authenticateHandler shows the "Sign In to Game Center" alert (e.g. didShowFullscreenSignIn) — even if the app does not have the Game Center capability enabled or any related entitlement (com.apple.developer.game-center). This alert only appears when the user is not signed in to Game Center in system settings. However, when testing the same code path on iOS app built with macOS 26 (Tahoe), the alert does not appear unless the proper capability and entitlement are included. This behavior is different from macOS 15 (Sequoia) + Xcode 15.x. Prior to the update, Game Center features did not work at all even with the OSX app without Capability and Entitlements. Steps to Reproduce Create a new OSX app target (App Sandbox enabled, no Game Center capability). Add minimal GameKit code: GKLocalPlayer.local.authenticateHandler = { _, _, _ in } Build OSX app and run on macOS 26 (Tahoe). Ensure Game Center is signed out in System Settings. Observe: “Sign In to Game Center” alert appears automatically. Expected Behavior When Game Center capability and entitlement are not present, authenticateHandler should fail silently, and no signIn alert should appear. Actual Behavior On OSX app, the Game Center signIn UI appears even without any Game Center capability or entitlement. On iOS app, this alert does not appear. *Build Configuration: built with the same condition. (macOS 26 + Xcode 26) Question Could you please confirm whether this behavior is an intentional change in macOS 26 or a bug only for OSX apps in the GameKit authentication flow? Thank you.
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Oct ’25
GameKit Leaderboards not working in iOS 26.2
Leaderboards working fine in iOS 26.1 but seem to be broken in 26.2 and also in the 26.3 developer beta. Players cannot submit scores and neither can they view scores on Apple's default leaderboards. Custom leaderboards that rely on pulling information using GameKit APIs also fail. Is there a workaround or patch for this?
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receivedTurnEventForMatch giving stale data
In my turn-based game, I receive GKListener event receivedTurnEventForMatch and decode the match.matchData. On occasion, the matchData is clearly stale and is from the previous turn. If I call the MatchMaker ViewController up and select that same match, the data is not stale, so it's not a matter of not calling endTurn. I have tried both loadMatchWithID and loadMatchesWithCompletionHandler after receiving the receivedTurnEventForMatch, but the data is still stale. Advice?
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Xcode 26 – "Manage Game Progress" not showing achievements/leaderboards on macOS
Hello, When testing GameKit "Manage Game Progress" in Xcode 26: On iOS devices, achievements, leaderboards, and party code data display and work correctly. On macOS devices, none of these data appear in "Manage Game Progress." Is this a known issue with macOS GameKit, or is there a limitation compared to iOS? If it is not a bug, is there any additional configuration needed to make achievements and leaderboards visible on macOS? I also included the GameKit bundle in my macOS app and enabled Enable Debug Mode in GameKit Configuration in the scheme options. Thank you.
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Sep ’25
GameKit Turn Based Matches Push Notifications
I'm developing a game that supports GameKit turn based matches. What I don't understand is this: Is tapping on the Game Center notification push messages the only way for the GKTurnBasedEventListener to trigger? What if someone misses the push message (swiping it away by accident or something like that) but still wants to join? Is there some inbox somewhere where the pending messages can be seen or fetched? Also it was mentioned in a very old WWDC video (from 2013, I think that's the latest with information about turn based matches) that the notification also includes a badge for the icon. However, I do not understand how to implement that. Is there any documentation for that?
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How does the automatch feature work in Game Kit?
I'm developing a turn based game. When I present the GKTurnBasedMatchmakerViewController players can opt in for automatch instead of selecting a specific friend as opponent. How exactly does the matching work if a player doesn't specify anything explicitly? Does Game Center send push notifications in a round robin fashion to all friends and the first one to accept is then matched as opponent? Is this documented somewhere?
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GKLocalPlayer save and fetch data to iCloud issue
Hi all I have two mystic issues with saving and fetching data to and from iCloud. Both repro only after first launch of an app. 1. [GKLocalPlayer fetchSavedGamesWithCompletionHandler:] After first attempt I can see 0 saved games (but i know that there is at least one saved game) and there is no any error. In case if I try fetch one more time (without any additional actions) even immediately after first attempt I receive saved games correctly (not 0) 2. [GKLocalPlayer saveGameData: withName: completionHandler:] After first attempt I can see error The requested operation could not be completed because local player has not been authenticated. In case if I try save one more time (without any additional actions) even immediately after first attempt I can save data successfully without any error I found the same issue in StackOverflow, but there are no fixes...
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Feb ’25
Transferring Apps with iCloud KVS
Hi All! I'm being asked to migrate an app which utilizes iCloud KVS (Key Value Storage). This ability is a new-ish feature, and the documentation about this is sparse [1]. Honestly, the entire documentation about the new iCloud transfer functionality seems to be missing. Same with Game Center / GameKit. While the docs say that it should work, I'd like to understand the process in more detail. Has anyone migrated an iCloud KVS app? What happens after the transfer goes through, but before the first release? Do I need to do anything special? I see that the Entitlements file has the TeamID in the Key Value store - is that fine? <key>com.apple.developer.ubiquity-kvstore-identifier</key> <string>$(TeamIdentifierPrefix)$(CFBundleIdentifier)</string> Can someone please share their experience? Thank you! [1] https://developer.apple.com/help/app-store-connect/transfer-an-app/overview-of-app-transfer
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Feb ’25
GKMatch.chooseBestHostingPlayer(_:) always returns nil player
I'm building a game with a client-server architecture. Using GKMatch.chooseBestHostingPlayer(_:) rarely works. When I started testing it today, it worked once at the very beginning, and since then it always succeeds on one client and returns nil on the other client. I'm testing with a Mac and an iPhone. Sometimes it fails on the Mac, sometimes on the iPhone. On the device that it succeeds on, the provided host can be the device itself or the other one. I created FB9583628 in August 2021, but after the Feedback Assistant team replied that they are not able to reproduce it, the feedback never went forward. import SceneKit import GameKit #if os(macOS) typealias ViewController = NSViewController #else typealias ViewController = UIViewController #endif class GameViewController: ViewController, GKMatchmakerViewControllerDelegate, GKMatchDelegate { var match: GKMatch? var matchStarted = false override func viewDidLoad() { super.viewDidLoad() GKLocalPlayer.local.authenticateHandler = authenticate } private func authenticate(_ viewController: ViewController?, _ error: Error?) { #if os(macOS) if let viewController = viewController { presentAsSheet(viewController) } else if let error = error { print(error) } else { print("authenticated as \(GKLocalPlayer.local.gamePlayerID)") let viewController = GKMatchmakerViewController(matchRequest: defaultMatchRequest())! viewController.matchmakerDelegate = self GKDialogController.shared().present(viewController) } #else if let viewController = viewController { present(viewController, animated: true) } else if let error = error { print(error) } else { print("authenticated as \(GKLocalPlayer.local.gamePlayerID)") let viewController = GKMatchmakerViewController(matchRequest: defaultMatchRequest())! viewController.matchmakerDelegate = self present(viewController, animated: true) } #endif } private func defaultMatchRequest() -> GKMatchRequest { let request = GKMatchRequest() request.minPlayers = 2 request.maxPlayers = 2 request.defaultNumberOfPlayers = 2 request.inviteMessage = "Ciao!" return request } func matchmakerViewControllerWasCancelled(_ viewController: GKMatchmakerViewController) { print("cancelled") } func matchmakerViewController(_ viewController: GKMatchmakerViewController, didFailWithError error: Error) { print(error) } func matchmakerViewController(_ viewController: GKMatchmakerViewController, didFind match: GKMatch) { self.match = match match.delegate = self startMatch() } func match(_ match: GKMatch, player: GKPlayer, didChange state: GKPlayerConnectionState) { print("\(player.gamePlayerID) changed state to \(String(describing: state))") startMatch() } func startMatch() { let match = match! if matchStarted || match.expectedPlayerCount > 0 { return } print("starting match with local player \(GKLocalPlayer.local.gamePlayerID) and remote players \(match.players.map({ $0.gamePlayerID }))") match.chooseBestHostingPlayer { host in print("host is \(String(describing: host?.gamePlayerID))") } } }
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Apr ’25
Game Center challenges and activities issues for released game
We have a released game in the App Store with Game Center Challenges. The challenges were working well in testing of the final version before the Game Center challenges went live. After release the activity that should take the player to the challenge in game results in this printout and we do not get informed by GKGameActivityListener of the activity happening in our code as we did before the Game Center challenges went live. “Invalid game activity definition. Failed to kick activity notification to GameKit. Error: Error Domain=GKErrorDomain Code=17 "(null)"” Also, Game Center reports that the are no challenges in GKChallengeDefinition.all even though there are ongoing challenges. The leaderboard results do get reported to Game Center though and show up as challenge entries in the Games app. At the moment we are trying to figure out if this is a problem on our end or a Game Center server issue.
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Sep ’25
MatchMaker VC not showing existing matches after upgrade.
Updated my app to include turn-based matches. Beta testing through FlightTest and all was well between iOS 18.x and 26.2 devices. One beta tester upgraded to 26.2 during beta testing and now when the MatchMaker VC is opened, it does not show existing matches. Worse, he can create new matches and play his turn, but the new match won't even show up in MMVC, even after opponent takes turn. My app has been reviewed and is ready for release, but I'd like to know how to solve this before I release. He has tried re-installing the app, including an updated FlightTest version that is the same as the about-to-be-released reviewed version.
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