• This is a OnlineSubsystemApple plugin for unreal engine 4, both c++ and blueprint supported.
• Does not need Apple Developer Program on Android and Windows.

Just 5 min https://youtu.be/ysZ-h2DjfGk

• Apple Account
  
• Ready iOS Device or Mac for Two-Factor Authentication
  
• You have to Activate Two-Factor Authentication
  

[OnlineSubsystemApple.OnlineIdentityApple]
ClientId=com.onlinesubsystem.apple.service
LoginRedirectUrl="https://onlinesubsystem.azurewebsites.net/api/apple/redirect"
CheckBackendUrl="https://onlinesubsystem.azurewebsites.net/api/apple/check"

[/Script/IOSRuntimeSettings.IOSRuntimeSettings]
bEnableSignInWithAppleSupport=True

• For read again DefaultEngine.ini

• Need build plugin your own project.
• Xcode 11 or later
• iOS 13 or later
• Uncomment OnlinesubsystemApple.Build.cs Line:86

After You edit DefaultEngine.ini (Step1) and Restart Editor (Step2). But still show Invlid_Request in SignIn process

• Check Double quotes LoginRedirectUrl and CheckBackendUrl.
  LoginRedirectUrl="https://onlinesubsystem.azurewebsites.net/api/apple/redirect"
  CheckBackendUrl="https://onlinesubsystem.azurewebsites.net/api/apple/check"
  

• Restart Unreal Editor. for read again DefaultEngine.ini.