AdamEssenmacher · AdamEssenmacher · Apr 10, 2026 · Apr 10, 2026 · Apr 10, 2026 · Apr 10, 2026
diff --git a/.gitignore b/.gitignore
@@ -3,6 +3,11 @@ bin
 obj
 output
 tools
+!tools/
+tools/*
+!tools/e2e/
+tools/e2e/*
+!tools/e2e/run-firebase-foundation.sh
 tmp-nugets
 *.userprefs
 *.DS_Store
@@ -15,4 +20,5 @@ _._
 externals
 artifacts
 *.user
-GoogleService-Info.plist
+GoogleService-Info.plist
+!tests/E2E/Firebase.Foundation/FirebaseFoundationE2E/GoogleService-Info.plist
diff --git a/source/Firebase/Analytics/ApiDefinition.cs b/source/Firebase/Analytics/ApiDefinition.cs
@@ -42,6 +42,7 @@ interface Analytics
 
 		// + (nullable NSString *)appInstanceID;
 		[Static]
+		[NullAllowed]
 		[Export ("appInstanceID")]
 		string AppInstanceId { get; }
 

diff --git a/source/Firebase/AppCheck/ApiDefinition.cs b/source/Firebase/AppCheck/ApiDefinition.cs
@@ -5,7 +5,7 @@
 
 namespace Firebase.AppCheck {
 	// typedef void (^)(FIRAppCheckToken *_Nullable token, NSError *_Nullable error)
-	delegate void TokenCompletionHandler (AppCheckToken token, NSError error);
+	delegate void TokenCompletionHandler ([NullAllowed] AppCheckToken token, [NullAllowed] NSError error);
 
 	interface IAppCheckProviderFactory { }
 
@@ -97,6 +97,7 @@ interface AppCheckToken {
 	[BaseType (typeof (NSObject), Name = "FIRAppCheckDebugProvider")]
 	interface AppCheckDebugProvider : IAppCheckProvider {
 		// -(instancetype _Nullable)initWithApp:(FIRApp * _Nonnull)app;
+		[return: NullAllowed]
 		[Export ("initWithApp:")]
 		NativeHandle Constructor (App app);
 
@@ -120,6 +121,7 @@ interface AppCheckDebugProviderFactory : AppCheckProviderFactory {
 	[BaseType (typeof (NSObject), Name = "FIRDeviceCheckProvider")]
 	interface DeviceCheckProvider : AppCheckProvider {
 		// -(instancetype _Nullable)initWithApp:(FIRApp * _Nonnull)app;
+		[return: NullAllowed]
 		[Export ("initWithApp:")]
 		NativeHandle Constructor (App app);
 	}
@@ -130,6 +132,7 @@ interface DeviceCheckProvider : AppCheckProvider {
 	[BaseType (typeof (NSObject), Name = "FIRAppAttestProvider")]
 	interface AppAttestProvider : AppCheckProvider {
 		// -(instancetype _Nullable)initWithApp:(FIRApp * _Nonnull)app;
+		[return: NullAllowed]
 		[Export ("initWithApp:")]
 		NativeHandle Constructor (App app);
 	}

diff --git a/source/Firebase/CloudFirestore/ApiDefinition.cs b/source/Firebase/CloudFirestore/ApiDefinition.cs
@@ -45,10 +45,10 @@ interface CollectionReference
 
 		// -(FIRDocumentReference * _Nonnull)addDocumentWithData:(NSDictionary<NSString *,id> * _Nonnull)data completion:(void (^ _Nullable)(NSError * _Nullable))completion;
 		[Export ("addDocumentWithData:completion:")]
-		DocumentReference AddDocument (NSDictionary<NSString, NSObject> nsData, AddDocumentCompletionHandler completion);
+		DocumentReference AddDocument (NSDictionary<NSString, NSObject> nsData, [NullAllowed] AddDocumentCompletionHandler completion);
 
 		[Wrap ("AddDocument (data == null ? null : NSDictionary<NSString, NSObject>.FromObjectsAndKeys (System.Linq.Enumerable.ToArray (data.Values), System.Linq.Enumerable.ToArray (data.Keys), data.Keys.Count), completion)")]
-		DocumentReference AddDocument (Dictionary<object, object> data, AddDocumentCompletionHandler completion);
+		DocumentReference AddDocument (Dictionary<object, object> data, [NullAllowed] AddDocumentCompletionHandler completion);
 	}
 
 	// @interface FIRDocumentChange : NSObject
@@ -247,6 +247,7 @@ interface DocumentSnapshot
 		SnapshotMetadata Metadata { get; }
 
 		// -(NSDictionary<NSString *,id> * _Nonnull)data;
+		[NullAllowed]
 		[Export ("data")]
 		NSDictionary<NSString, NSObject> Data { get; }
 

diff --git a/source/Firebase/CloudFunctions/ApiDefinition.cs b/source/Firebase/CloudFunctions/ApiDefinition.cs
@@ -48,6 +48,7 @@ interface CloudFunctions
 		HttpsCallable HttpsCallable(string name);
 
 		// @property(nonatomic, readonly, nullable) NSString *emulatorOrigin;
+		[NullAllowed]
 		[Export("emulatorOrigin")]
 		string EmulatorOrigin { get; }
 

diff --git a/source/Firebase/CloudMessaging/ApiDefinition.cs b/source/Firebase/CloudMessaging/ApiDefinition.cs
@@ -37,9 +37,9 @@ interface IMessagingDelegate
 	[BaseType (typeof (NSObject), Name = "FIRMessagingDelegate")]
 	interface MessagingDelegate
 	{
-		// @optional -(void)messaging:(FIRMessaging * _Nonnull)messaging didReceiveRegistrationToken:(NSString * _Nonnull)fcmToken;
+		// @optional -(void)messaging:(FIRMessaging * _Nonnull)messaging didReceiveRegistrationToken:(NSString * _Nullable)fcmToken;
 		[Export ("messaging:didReceiveRegistrationToken:")]
-		void DidReceiveRegistrationToken (Messaging messaging, string fcmToken);
+		void DidReceiveRegistrationToken (Messaging messaging, [NullAllowed] string fcmToken);
 	}
 
 	// @interface FIRMessaging : NSObject
@@ -108,7 +108,7 @@ interface Messaging
 		// -(void)subscribeToTopic:(NSString * _Nonnull)topic completion:(nullable FIRMessagingTopicOperationCompletion)completion;
 		[Async]
 		[Export ("subscribeToTopic:completion:")]
-		void Subscribe (string topic, MessagingTopicOperationCompletionHandler completion);
+		void Subscribe (string topic, [NullAllowed] MessagingTopicOperationCompletionHandler completion);
 
 		// -(void)unsubscribeFromTopic:(NSString * _Nonnull)topic;
 		[Export ("unsubscribeFromTopic:")]
@@ -117,7 +117,7 @@ interface Messaging
 		//-(void)unsubscribeFromTopic:(NSString * _Nonnull)topic completion:(nullable FIRMessagingTopicOperationCompletion)completion;
 		[Async]
 		[Export ("unsubscribeFromTopic:completion:")]
-		void Unsubscribe (string topic, MessagingTopicOperationCompletionHandler completion);
+		void Unsubscribe (string topic, [NullAllowed] MessagingTopicOperationCompletionHandler completion);
 
 		// -(FIRMessagingMessageInfo * _Nonnull)appDidReceiveMessage:(NSDictionary * _Nonnull)message;
 		[Export ("appDidReceiveMessage:")]

diff --git a/source/Firebase/Core/ApiDefinition.cs b/source/Firebase/Core/ApiDefinition.cs
@@ -32,6 +32,7 @@ interface App : INativeObject
 
 		// +(FIRApp * _Nullable)defaultApp;
 		[Static]
+		[NullAllowed]
 		[Export ("defaultApp")]
 		App DefaultInstance { get; }
 
@@ -96,7 +97,6 @@ interface Options : INSCopying
 		string ApiKey { get; set; }
 
 		// @property(nonatomic, copy) NSString *bundleID;
-		[NullAllowed]
 		[Export ("bundleID")]
 		string BundleId { get; set; }
 

diff --git a/source/Firebase/Crashlytics/ApiDefinition.cs b/source/Firebase/Crashlytics/ApiDefinition.cs
@@ -23,17 +23,17 @@ interface Crashlytics
 		[Export ("log:")]
 		void Log (string message);
 
-		// -(void)setCustomValue:(id _Nonnull)value forKey:(NSString * _Nonnull)key;
+		// -(void)setCustomValue:(id _Nullable)value forKey:(NSString * _Nonnull)key;
 		[Export ("setCustomValue:forKey:")]
-		void SetCustomValue (NSObject value, string key);
+		void SetCustomValue ([NullAllowed] NSObject value, string key);
 
 		// -(void)setCustomKeysAndValues:(NSDictionary * _Nonnull)keysAndValues;
 		[Export ("setCustomKeysAndValues:")]
 		void SetCustomKeysAndValues (NSDictionary<NSString, NSObject> keysAndValues);
 
-		// -(void)setUserID:(NSString * _Nonnull)userID;
+		// -(void)setUserID:(NSString * _Nullable)userID;
 		[Export ("setUserID:")]
-		void SetUserId (string userId);
+		void SetUserId ([NullAllowed] string userId);
 
 		// -(void)recordError:(NSError * _Nonnull)error __attribute__((swift_name("record(error:)")));
 		[Export ("recordError:")]
@@ -131,16 +131,16 @@ interface CrashlyticsReport {
 		[Export ("log:")]
 		void Log (string msg);
 
-		// -(void)setCustomValue:(id _Nonnull)value forKey:(NSString * _Nonnull)key;
+		// -(void)setCustomValue:(id _Nullable)value forKey:(NSString * _Nonnull)key;
 		[Export ("setCustomValue:forKey:")]
-		void SetCustomValue (NSObject value, string key);
+		void SetCustomValue ([NullAllowed] NSObject value, string key);
 
 		// -(void)setCustomKeysAndValues:(NSDictionary * _Nonnull)keysAndValues;
 		[Export ("setCustomKeysAndValues:")]
 		void SetCustomKeysAndValues (NSDictionary<NSString, NSObject>  keysAndValues);
 
-		// -(void)setUserID:(NSString * _Nonnull)userID;
+		// -(void)setUserID:(NSString * _Nullable)userID;
 		[Export ("setUserID:")]
-		void SetUserID (string userID);
+		void SetUserID ([NullAllowed] string userID);
 	}
 }
diff --git a/source/Firebase/Database/ApiDefinition.cs b/source/Firebase/Database/ApiDefinition.cs
@@ -463,7 +463,7 @@ interface DatabaseReference
 
 		// -(void)runTransactionBlock:(FIRTransactionResult * _Nonnull (^ _Nonnull)(FIRMutableData * _Nonnull))block andCompletionBlock:(void (^ _Nullable)(NSError * _Nullable, BOOL, FIRDataSnapshot * _Nullable))completionBlock withLocalEvents:(BOOL)localEvents;
 		[Export ("runTransactionBlock:andCompletionBlock:withLocalEvents:")]
-		void RunTransaction (DatabaseReferenceTransactionHandler transactionHandler, DatabaseReferenceTransactionCompletionHandler completionBlock, bool localEvents);
+		void RunTransaction (DatabaseReferenceTransactionHandler transactionHandler, [NullAllowed] DatabaseReferenceTransactionCompletionHandler completionBlock, bool localEvents);
 
 		// -(NSString * _Nonnull)description;
 		[New]
@@ -480,6 +480,7 @@ interface DatabaseReference
 		DatabaseReference Root { get; }
 
 		// @property (readonly, nonatomic, strong) NSString * _Nonnull key;
+		[NullAllowed]
 		[Export ("key", ArgumentSemantic.Strong)]
 		string Key { get; }
 

diff --git a/source/Firebase/PerformanceMonitoring/ApiDefinition.cs b/source/Firebase/PerformanceMonitoring/ApiDefinition.cs
@@ -13,6 +13,7 @@ namespace Firebase.PerformanceMonitoring
 	interface HttpMetric : PerformanceAttributable
 	{
 		// -(instancetype _Nullable)initWithURL:(NSURL * _Nonnull)URL HTTPMethod:(FIRHTTPMethod)httpMethod;
+		[return: NullAllowed]
 		[Export ("initWithURL:HTTPMethod:")]
 		NativeHandle Constructor (NSUrl url, HttpMethod httpMethod);
 

diff --git a/source/Firebase/Storage/ApiDefinition.cs b/source/Firebase/Storage/ApiDefinition.cs
@@ -295,15 +295,15 @@ interface StorageReference
 		[Export ("writeToFile:completion:")]
 		StorageDownloadTask WriteToFile (NSUrl fileURL, [NullAllowed] StorageWriteToFileCompletionHandler completion);
 
-		// -(void)listAllWithCompletion:(void (^ _Nonnull)(FIRStorageListResult * _Nonnull, NSError * _Nullable))completion;
+		// -(void)listAllWithCompletion:(void (^ _Nonnull)(FIRStorageListResult * _Nullable, NSError * _Nullable))completion;
 		[Export ("listAllWithCompletion:")]
 		void ListAll (Action<StorageListResult, NSError> completion);
 
-		// -(void)listWithMaxResults:(int64_t)maxResults completion:(void (^ _Nonnull)(FIRStorageListResult * _Nonnull, NSError * _Nullable))completion;
+		// -(void)listWithMaxResults:(int64_t)maxResults completion:(void (^ _Nonnull)(FIRStorageListResult * _Nullable, NSError * _Nullable))completion;
 		[Export ("listWithMaxResults:completion:")]
 		void List (long maxResults, Action<StorageListResult, NSError> completion);
 
-		// -(void)listWithMaxResults:(int64_t)maxResults pageToken:(NSString * _Nonnull)pageToken completion:(void (^ _Nonnull)(FIRStorageListResult * _Nonnull, NSError * _Nullable))completion;
+		// -(void)listWithMaxResults:(int64_t)maxResults pageToken:(NSString * _Nonnull)pageToken completion:(void (^ _Nonnull)(FIRStorageListResult * _Nullable, NSError * _Nullable))completion;
 		[Export ("listWithMaxResults:pageToken:completion:")]
 		void List (long maxResults, string pageToken, Action<StorageListResult, NSError> completion);
 

diff --git a/tests/E2E/Firebase.Foundation/FirebaseFoundationE2E/AppDelegate.cs b/tests/E2E/Firebase.Foundation/FirebaseFoundationE2E/AppDelegate.cs
@@ -0,0 +1,26 @@
+using Foundation;
+using UIKit;
+
+namespace FirebaseFoundationE2E;
+
+[Register("AppDelegate")]
+public sealed class AppDelegate : UIApplicationDelegate
+{
+    public override UIWindow? Window { get; set; }
+
+    public override bool FinishedLaunching(UIApplication application, NSDictionary? launchOptions)
+    {
+#pragma warning disable CA1422
+        Window = new UIWindow(UIScreen.MainScreen.Bounds);
+#pragma warning restore CA1422
+
+        var statusViewController = new StatusViewController();
+        Window.RootViewController = statusViewController;
+        Window.MakeKeyAndVisible();
+        statusViewController.LoadViewIfNeeded();
+
+        _ = FirebaseSelfTestRunner.RunAsync(statusViewController);
+
+        return true;
+    }
+}
diff --git a/tests/E2E/Firebase.Foundation/FirebaseFoundationE2E/E2EContracts.cs b/tests/E2E/Firebase.Foundation/FirebaseFoundationE2E/E2EContracts.cs
@@ -0,0 +1,26 @@
+namespace FirebaseFoundationE2E;
+
+public sealed class FirebaseE2ERunResult
+{
+    public string BundleId { get; set; } = string.Empty;
+    public string? DefaultAppName { get; set; }
+    public string? GoogleAppId { get; set; }
+    public string? ProjectId { get; set; }
+    public string? FirebaseVersion { get; set; }
+    public string? InstallationsIdPreview { get; set; }
+    public bool Success { get; set; }
+    public DateTimeOffset StartedAtUtc { get; set; }
+    public DateTimeOffset CompletedAtUtc { get; set; }
+    public string? FatalError { get; set; }
+    public List<FirebaseE2ETestCaseResult> Cases { get; } = new();
+}
+
+public sealed class FirebaseE2ETestCaseResult
+{
+    public string Name { get; set; } = string.Empty;
+    public bool Success { get; set; }
+    public long DurationMs { get; set; }
+    public string? Message { get; set; }
+    public string? ExceptionType { get; set; }
+    public string? Detail { get; set; }
+}
diff --git a/tests/E2E/Firebase.Foundation/FirebaseFoundationE2E/E2ELogger.cs b/tests/E2E/Firebase.Foundation/FirebaseFoundationE2E/E2ELogger.cs
@@ -0,0 +1,9 @@
+namespace FirebaseFoundationE2E;
+
+public static class E2ELogger
+{
+    public static void WriteLine(string message)
+    {
+        Console.WriteLine(message);
+    }
+}
diff --git a/tests/E2E/Firebase.Foundation/FirebaseFoundationE2E/FirebaseFoundationE2E.csproj b/tests/E2E/Firebase.Foundation/FirebaseFoundationE2E/FirebaseFoundationE2E.csproj
@@ -0,0 +1,67 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <TargetFrameworks>net9.0-ios;net9.0-maccatalyst</TargetFrameworks>
+    <RuntimeIdentifiers Condition="!Exists('$(ProjectAssetsFile)')">iossimulator-arm64;ios-arm64;maccatalyst-arm64</RuntimeIdentifiers>
+    <RuntimeIdentifiers Condition="Exists('$(ProjectAssetsFile)')"></RuntimeIdentifiers>
+    <OutputType>Exe</OutputType>
+    <Nullable>enable</Nullable>
+    <ImplicitUsings>true</ImplicitUsings>
+    <SupportedOSPlatformVersion>15.0</SupportedOSPlatformVersion>
+    <RootNamespace>FirebaseFoundationE2E</RootNamespace>
+    <AssemblyName>FirebaseFoundationE2E</AssemblyName>
+    <IPhoneResourcePrefix>Resources</IPhoneResourcePrefix>
+    <Platforms>AnyCPU;iPhoneSimulator;iPhone</Platforms>
+    <Configurations>Debug;Release</Configurations>
+    <IsPackable>false</IsPackable>
+    <ProvisioningType>manual</ProvisioningType>
+    <EnableNullabilityValidation>false</EnableNullabilityValidation>
+  </PropertyGroup>
+
+  <PropertyGroup Condition="'$(EnableNullabilityValidation)' == 'true'">
+    <DefineConstants>$(DefineConstants);ENABLE_NULLABILITY_VALIDATION</DefineConstants>
+  </PropertyGroup>
+
+  <PropertyGroup Condition="'$(TargetFramework)' == 'net9.0-ios' and '$(Platform)' == ''">
+    <Platform>iPhoneSimulator</Platform>
+  </PropertyGroup>
+
+  <PropertyGroup Condition="'$(TargetFramework)' == 'net9.0-ios' and '$(RuntimeIdentifier)' == ''">
+    <RuntimeIdentifier>iossimulator-arm64</RuntimeIdentifier>
+  </PropertyGroup>
+
+  <PropertyGroup Condition="'$(TargetFramework)' == 'net9.0-maccatalyst' and '$(RuntimeIdentifier)' == ''">
+    <RuntimeIdentifier>maccatalyst-arm64</RuntimeIdentifier>
+  </PropertyGroup>
+
+  <PropertyGroup Condition="'$(Configuration)' == 'Release'">
+    <MtouchLink>None</MtouchLink>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <None Remove="GoogleService-Info.plist" Condition="Exists('GoogleService-Info.plist')" />
+    <BundleResource Include="GoogleService-Info.plist" Condition="Exists('GoogleService-Info.plist')" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <PackageReference Include="AdamE.Firebase.iOS.Analytics" Version="12.6.0" />
+    <PackageReference Include="AdamE.Firebase.iOS.Core" Version="12.6.0" />
+    <PackageReference Include="AdamE.Firebase.iOS.Installations" Version="12.6.0" />
+    <PackageReference Include="AdamE.Google.iOS.GoogleAppMeasurement" Version="12.6.0" />
+    <PackageReference Include="AdamE.Google.iOS.GoogleDataTransport" Version="10.1.0.5" />
+    <PackageReference Include="AdamE.Google.iOS.GoogleUtilities" Version="8.1.0.3" />
+    <PackageReference Include="AdamE.Google.iOS.Nanopb" Version="3.30910.0.5" />
+    <PackageReference Include="AdamE.Google.iOS.PromisesObjC" Version="2.4.0.5" />
+  </ItemGroup>
+
+  <ItemGroup Condition="'$(EnableNullabilityValidation)' == 'true'">
+    <PackageReference Include="AdamE.Firebase.iOS.CloudFirestore" Version="12.6.0" />
+  </ItemGroup>
+
+  <ItemGroup Condition="'$(EnableNullabilityValidation)' == 'true'">
+    <PackageReference Include="AdamE.Firebase.iOS.AppCheck" Version="12.6.0" />
+    <PackageReference Include="AdamE.Firebase.iOS.CloudMessaging" Version="12.6.0" />
+    <PackageReference Include="AdamE.Firebase.iOS.Crashlytics" Version="12.6.0" />
+    <PackageReference Include="AdamE.Firebase.iOS.Database" Version="12.6.0" />
+    <PackageReference Include="AdamE.Firebase.iOS.PerformanceMonitoring" Version="12.6.0" />
+  </ItemGroup>
+</Project>