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

GameKit Documentation

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Clarifying when Game Center activity events fire relative to authentication
Hello, In our game we enforce an age gate before showing Game Center sign‑in. Only after the user passes the age gate do we call GKLocalPlayer.localPlayer.authenticateHandler. The reason I’m asking is that we want to reliably detect if the game was launched from a Game Center activity in the Games app (iOS 26+). If the user prefers to enter via activities, we don’t want to miss that event during cold start. Our current proposal is: Register a GKLocalPlayerListener early in didFinishLaunchingWithOptions: so the app is ready to catch events. Queue any incoming events in our dispatcher. Only process those events after the user passes the age gate and authentication succeeds. My questions are: Does player:wantsToPlayGameActivity:completionHandler: ever fire before authentication, or only after the local player is authenticated? If it only fires after authentication, is our “register early but gate processing” approach the correct way to ensure we don’t miss activity launches? Is there any recommended pattern to distinguish “activity launch” vs. “normal launch” in this age‑gate scenario? We want to respect Apple’s age gate requirements, but also ensure activity launches are not lost if the user prefers that entry point. Sorry if this is a stupid question — I just want to be sure we’re following the right pattern. Thanks for any clarification or best‑practice guidance!
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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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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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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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2 high scores vanished
In my game 854159268 (com.1791entertainment.qugame), in my quMostRecent3 leaderboard, the top 2 entries have 'vanished'. They were there yesterday. I know these players have played today, as I see their scores on other leaderboards. Any ideas how to get these back? These 2 players (me and my tester) are both TestFlight ing - not sure if that changes things.
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iOS Matchmaker ViewController Info Button
I'm updating an existing distributed game to add turn-based matches. When the Matchmaker ViewController Info Button next to a game is pressed, the results vary: iOS 15.x - Button under avatar says "Accept Invite" or "View Game" (depending on if invite has already been accepted) iOS 18.x - Button always says "App Store" - I assume that means it would lead one to the App store to install the game. Both devices (iPad 15.x and iPhone 18.x) have the same version of the game installed. The results are the same when running in the simulator. When the game is released, I assume this button will work properly, no?
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GKLeaderboard.loadLeaderboards returns empty array
After authenticating the user I'm loading my Game Center leaderboards like this: let leaderboards = try await GKLeaderboard.loadLeaderboards(IDs: [leaderboardID]) This is working fine, but there are times when this just returns an empty array. When I encounter this situation, the array remains empty for several hours when retrying, but then at some point it suddenly starts working again. Is this a known issue? Or am I hitting some kind of quota maybe (as I do it quite often while developing my game)?. Edit: My leaderboards are grouped in sets if that makes any difference here.
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392
Dec ’25
How does Game Kit offline leaderboard submission work?
I do not understand how offline leaderboard submission is supposed to work in Game Kit: While the documentation briefly states that offline submission is supported, how is that even possible when you first have to fetch a leaderboard object in order to then call its submitScore function? How can I get the leaderboard object in the first place when offline? Can anyone enlighten me how this works? Or maybe point me to some relevant documentation?
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Dec ’25
Game Center fetchSavedGames sometimes returns empty list of games, although it works correctly on the next tries
I have implemented the Game Center for authentication and saving player's game data. Both authentication and saving player's data works correctly all the time, but there is a problem with fetching and loading the data. The game works like this: At the startup, I start the authentication After the player successfully logs in, I start loading the player's data by calling fetchSavedGames method If a game data exists for the player, I receive a list of SavedGame object containing the player's data The problem is that after I uninstall the game and install it again, sometimes the SavedGame list is empty(step 3). But if I don't uninstall the game and reopen the game, this process works fine. Here's the complete code of Game Center implementation: class GameCenterHandler { public func signIn() { GKLocalPlayer.local.authenticateHandler = { viewController, error in if let viewController = viewController { viewController.present(viewController, animated: false) return } if error != nil { // Player could not be authenticated. // Disable Game Center in the game. return } // Auth successfull self.load(filename: "TestFileName") } } public func save(filename: String, data: String) { if GKLocalPlayer.local.isAuthenticated { GKLocalPlayer.local.saveGameData(Data(data.utf8), withName: filename) { savedGame, error in if savedGame != nil { // Data saved successfully } if error != nil { // Error in saving game data! } } } else { // Error in saving game data! User is not authenticated" } } public func load(filename: String) { if GKLocalPlayer.local.isAuthenticated { GKLocalPlayer.local.fetchSavedGames { games, error in if let game = games?.first(where: {$0.name == filename}){ game.loadData { data, error in if data != nil { // Data loaded successfully } if error != nil { // Error in loading game data! } } } else { // Error in loading game data! Filename not found } } } else { // Error in loading game data! User is not authenticated } } } I have also added Game Center and iCloud capabilities in xcode. Also in the iCloud section, I selected the iCloud Documents and added a container. I found a simillar question here but it doesn't make things clearer.
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Dec ’25
Turn-Based Game and Invitations
I have two devices (iPod, iPhone), each using a different Apple ID. I have an existing game to which I'm adding TBM. When the iPod invites the iPhone, it sends an iMessage invite to the iPhone; when I click on that message, I get "Retrieving", then Game Center in Settings is opened, not my App (same version installed on both devices). I start my App on the iPhone and that match is not shown in the Matchmaker View Controller. When I send an invite from the iPhone to the iPod and I click on the iMessage invite, the app starts but the match isn't listed in the MatchMaker ViewController on the iPod (but is on the iPhone). In addition, when I click on the info circle on the iPhone, it who's the two players and "App Store" under the Game Center name. However, When I do the same on the iPod, it has a "Play your turn" there. Any ideas?
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Nov ’25
Game Porting Toolkit installation fails: CMake compatibility error in game-porting-toolkit-compiler
I'm encountering a build failure when trying to install the Game Porting Toolkit via Homebrew. The installation fails during the game-porting-toolkit-compiler dependency build phase with a CMake compatibility error. Error Message: CMake Error at CMakeLists.txt:3 (cmake_minimum_required): Compatibility with CMake < 3.5 has been removed from CMake. Update the VERSION argument <min> value. Or, use the <min>...<max> syntax to tell CMake that the project requires at least <min> but has been updated to work with policies introduced by <max> or earlier. Or, add -DCMAKE_POLICY_VERSION_MINIMUM=3.5 to try configuring anyway. -- Configuring incomplete, errors occurred! Environment: macOS: 15.6.1 (Sequoia) Homebrew: 5.0.1 CMake: 3.20.2 Architecture: x86_64 (via Rosetta) Formula: apple/apple/game-porting-toolkit-compiler v0.1 Source: crossover-sources-22.1.1.tar.gz Steps to Reproduce: Install x86_64 Homebrew for Rosetta compatibility Run: arch -x86_64 /usr/local/bin/brew install apple/apple/game-porting-toolkit Build fails during dependency installation Root Cause: The LLVM/Clang sources included in crossover-sources-22.1.1.tar.gz contain a CMakeLists.txt file that specifies a minimum CMake version lower than 3.5. Modern CMake versions (3.5+) have removed backward compatibility with these older version requirements. Potential Solutions: Update the Homebrew formula to patch the CMakeLists.txt with cmake_minimum_required(VERSION 3.5) or higher Update to newer CrossOver sources with updated CMake requirements Add the -DCMAKE_POLICY_VERSION_MINIMUM=3.5 flag to the CMake build command in the formula Is this a known issue? Are there plans to update the formula or the source package to resolve this compatibility problem? Any guidance on a workaround would be appreciated. Full log available at: /Users/kentarovadney/Library/Logs/Homebrew/game-porting-toolkit-compiler/02.cmake.log Thanks for any assistance!
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Nov ’25
Game Center leaderboards not posting scores
My app is live but the leaderboards still aren’t updating. App was built with unreal engine 5 with blueprints. I have the leaderboard stat info entered into the node for write integer to leaderboard and a node for show platform specific leaderboard. The leaderboards are shown as live on app connect. When I run the app, the Game Center login functions and the leaderboard interface launches as expected but it just lists a group of friends to invite. There are no scores listed and it says number of players 0 even though I have scored on two different devices and accounts. I have the Game Center entitlement added in Xcode. Not sure where else to look.
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Nov ’25
GKLocalPlayer.isUnderAge always returns true on mac with an intel chips
Hello, I'm working on a game that features online multiplayer. The game is developed using Unity and Apple Unity plugins. The "isUnderAge" property restricts the online multiplayer feature. Everything works as expected on all platforms (Mac, iPhone, iPad, AppleTV, and visionPro) except on Macs equipped with an Intel chip. Using the same iCloud and GameCenter, with no restrictions enabled, "isUnderAge" returns false, as expected, but on Mac equipped with an Intel chip, it returns true. Is there any restriction or compatibility issue with those chips? Is there a workaround? Thanks
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Nov ’25
Crash occurring when authenticating user for Game Center
I am using the latest version of the Game Center plugin for Unity and have noticed that my game will crash on launch when trying to authenticate. I've tried this in an empty project with just the plugin and it still crashes with this exception. GfxDevice: creating device client; threaded=1; jobified=0 Initializing Metal device caps: Apple A14 GPU Initialize engine version: 2022.3.62f2 (7670c08855a9) 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. And the area in the native code that is triggering the crash is this inside the GKLocalPlayer_SetAuthenticateHandler function `_onAuthenticate!(tid, _mostRecentAuthenticatePlayer!.passRetainedUnsafeMutablePointer()); I am using Unity 2022.3.62f2 and MacOS 15.6 with iOS 18.6.2 which based on the min specs for the plugin we should be within spec. I have also included this message because I thought it might help too `terminating due to uncaught exception of type Il2CppExceptionWrapper Could not import Swift modules for translation unit: failed to get module "GameKitWrapper" from AST context: error: 'GKErrorCodeExtension.h' file not found in file included from :1: error: could not build Objective-C module 'GameKitWrapper' warning: Ignoring missing VFS file: /Users/james/Library/Developer/Xcode/DerivedData/GameKitWrapper-dzawbtxqdxdviiakfxmfunexppqv/Build/Intermediates.noindex/GameKitWrapper.build/Release-iphoneos/GameKitWrapper-bc72bd3638f4d2956cac9b00e84c1a7d-VFS-iphoneos/all-product-headers.yaml This is the likely root cause for any subsequent compiler errors.warning: Ignoring missing VFS file: /Users/bill/Library/Developer/Xcode/DerivedData/GameKitWrapper-dzawbtxqdxdviiakfxmfunexppqv/Build/Intermediates.noindex/GameKitWrapper.build/Release-iphoneos/GameKitWrapper iOS.build/unextended-module-overlay.yaml This is the likely root cause for any subsequent compiler errors.warning: TypeSystemSwiftTypeRef::GetNumChildren: had to engage SwiftASTContext fallback for type $syyXCD I've also attached the script that I am using for authentication, this script runs on the first scene. GameCenterManager.cs
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Nov ’25
GKMatch rule-based matching. Can't match more than 3 people.
Matchmaking rules https://developer.apple.com/documentation/gamekit/matchmaking-rules?language=objc AppStoreConnectApi rules https://developer.apple.com/documentation/appstoreconnectapi/rules?language=objc ・Environment Unity 6000.2.2f1 XCode 16.1 iOS 26 3 iPhones ・AppStoreConnectApi rules "type": "gameCenterMatchmakingRuleSets", "id": "f6a88caf-85db-42bf-xxxxxxxxxxxxxxxxxxxx", "attributes": { "referenceName": "co.mygame.RuleSets.GvERandom34", "ruleLanguageVersion": 1, "minPlayers": 3, "maxPlayers": 4 }, "type": "gameCenterMatchmakingRules", "id": "6afa68ce-4d2c-496f-xxxxxxxxxxxxxxxxxxxx", "attributes": { "referenceName": "GameVersion", "description": "Check Game Version. GvERandom34", "type": "COMPATIBLE", "expression": "requests[0].properties.gameVersion == requests[1].properties.gameVersion", "weight": null }, "type": "gameCenterMatchmakingQueues", "id": "7fb645ef-4eca-4510-xxxxxxxxxxxxxxxxxxxx", "attributes": { "referenceName": "co.mygame.que.GvERandom34", "classicMatchmakingBundleIds": [] }, ・Objective-C Execution code queueName = "co.mygame.que.GvERandom34" keyStr = "gameVersion " valueStr = "1.0" - (void)MatchQueueParamStr1Start:(NSString*)queueName keyStr:(NSString*)keyStr valueStr:(NSString*)valueStr { if (@available(iOS 17.2, tvOS 17.2, macOS 14.2, visionOS 1.1, *) == NO) { DBGLOG(@"MatchQueueParamStr1Start Not support."); return; } self->_matchMakingFlag = YES; self->_matchFinishFlag = NO; self->_myMatch = nil; GKMatchRequest *req = [[GKMatchRequest alloc] init]; if (@available(iOS 17.2, tvOS 17.2, macOS 14.2, visionOS 1.1, *)) { req.queueName = queueName; req.properties = @{keyStr: valueStr}; } [[GKMatchmaker sharedMatchmaker] findMatchForRequest:req withCompletionHandler: ^(GKMatch *match, NSError *error) { if (error) { [self SetupErrorInfo:error descriptionText:@"findMatchForRequest"]; } else if(match) { self->_myMatch = match; self->_myMatch.delegate = self; } self->_matchMakingFlag = NO; self->_matchFinishFlag = YES; }]; } ・ I'm trying to match with three devices. Matching doesn't work. 5 minutes later times out. What's the problem?
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Nov ’25
Issues building Unity plug-in project: Cannot locate native library Apple.Core/Apple.GameKit for iOS
I'm having issues getting a well built package from the Apple Unity Plug-in project. When building the my game project in Unity the following error is printed to the console: Apple.Core.AppleNativeLibraryUtility] Cannot locate a Debug or Release Apple.Core native library for iOS. Please ensure that the build invocation (build.py, xcodebuild, or Xcode) compiled cleanly and that the build was configured to support Debug on iOS. As far as I can tell the build did compile cleanly, but I might be missing something. If anyone can see what I'm doing wrong or has any insight it would be greatly appreciated. Setup is the following: macOS Tahoe 26 Beta Xcode-beta Version 26.0 beta 3 (17A5276g) Unity Plug-in branch: 2025-beta1 Unity game project version: 2022.3.60f M1 Macbook Pro The built packages have been imported into the game project through the Unity Package Manager using the tarball option pointing to the built packages from the Unity Plug-in project. The Unity Plug-in project has been built using the build.py file with the following: python3 build.py -m iOS iPhoneSimulator -p Core GameKit CoreHaptics GameController -k all The output is available in the attached file. build-output.txt Here's an image of the NativeLibraries~ folder inside the built Apple.Core package.
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Oct ’25