diff --git a/.gitignore b/.gitignore
index be6008e2c..d86b432e3 100644
--- a/.gitignore
+++ b/.gitignore
@@ -28,6 +28,8 @@ gcs_key_file.json
 *_build/
 cmake-build-*/
 testing/test_framework/external/
+CMakeFiles/
+CMakeCache.txt
 
 # XCode user specific folders
 **/xcuserdata/
diff --git a/app/src/include/firebase/app.h b/app/src/include/firebase/app.h
index f32f8bf33..03f0ad2dd 100644
--- a/app/src/include/firebase/app.h
+++ b/app/src/include/firebase/app.h
@@ -571,11 +571,8 @@ class App {
   /// Get the App with the given name, or nullptr if none have been created.
   static App* GetInstance(const char* name);
 
-#if !defined(DOXYGEN)
-  // Hidden from the public documentation for now
   /// Get all the apps, including the default one.
   static std::vector<App*> GetApps();
-#endif  // !defined(DOXYGEN)
 
 #ifndef SWIG
 // <SWIG>
diff --git a/auth/src/android/auth_android.cc b/auth/src/android/auth_android.cc
index 7b588dbb9..2f8ccda64 100644
--- a/auth/src/android/auth_android.cc
+++ b/auth/src/android/auth_android.cc
@@ -17,6 +17,8 @@
 #include <assert.h>
 #include <jni.h>
 
+#include <string>
+
 #include "app/src/assert.h"
 #include "app/src/embedded_file.h"
 #include "app/src/include/firebase/internal/mutex.h"
@@ -53,6 +55,7 @@ using util::JniStringToString;
   X(RemoveIdTokenListener, "removeIdTokenListener",                            \
     "(Lcom/google/firebase/auth/FirebaseAuth$IdTokenListener;)V"),             \
   X(SignOut, "signOut", "()V"),                                                \
+  X(UseEmulator, "useEmulator", "(Ljava/lang/String;I)V"),                     \
   X(FetchSignInMethodsForEmail, "fetchSignInMethodsForEmail",                  \
     "(Ljava/lang/String;)"                                                     \
     "Lcom/google/android/gms/tasks/Task;"),                                    \
@@ -185,6 +188,31 @@ void UpdateCurrentUser(AuthData* auth_data) {
   }
 }
 
+const char* const kEmulatorLocalHost = "10.0.2.2";
+const char* const kEmulatorPort = "9099";
+void CheckEmulator(AuthData* auth_data) {
+  JNIEnv* env = Env(auth_data);
+
+  // Use emulator as long as this env variable is set, regardless its value.
+  if (std::getenv("USE_AUTH_EMULATOR") == nullptr) {
+    LogDebug("Using Auth Prod for testing.");
+    return;
+  }
+
+  // Use AUTH_EMULATOR_PORT if it is set to non empty string,
+  // otherwise use the default port.
+  uint32_t port = std::stoi(kEmulatorPort);
+  if (std::getenv("AUTH_EMULATOR_PORT") != nullptr) {
+    port = std::stoi(std::getenv("AUTH_EMULATOR_PORT"));
+  }
+
+  jstring j_host = env->NewStringUTF(kEmulatorLocalHost);
+  env->CallVoidMethod(AuthImpl(auth_data),
+                      auth::GetMethodId(auth::kUseEmulator), j_host, port);
+  env->DeleteLocalRef(j_host);
+  firebase::util::CheckAndClearJniExceptions(env);
+}
+
 // Release cached Java classes.
 static void ReleaseClasses(JNIEnv* env) {
   ReleaseAuthClasses(env);
@@ -269,6 +297,8 @@ void Auth::InitPlatformAuth(AuthData* auth_data) {
   // Ensure our User is in-line with underlying API's user.
   // It's possible for a user to already be logged-in on start-up.
   UpdateCurrentUser(auth_data);
+
+  CheckEmulator(auth_data);
 }
 
 void Auth::DestroyPlatformAuth(AuthData* auth_data) {
diff --git a/auth/src/desktop/auth_desktop.h b/auth/src/desktop/auth_desktop.h
index 6210d4771..2d407cab1 100644
--- a/auth/src/desktop/auth_desktop.h
+++ b/auth/src/desktop/auth_desktop.h
@@ -16,6 +16,7 @@
 #define FIREBASE_AUTH_SRC_DESKTOP_AUTH_DESKTOP_H_
 
 #include <memory>
+#include <string>
 
 #include "app/rest/request.h"
 #include "app/src/scheduler.h"
diff --git a/auth/src/desktop/rpcs/auth_request.cc b/auth/src/desktop/rpcs/auth_request.cc
index 4db7ac46a..c9af69f78 100644
--- a/auth/src/desktop/rpcs/auth_request.cc
+++ b/auth/src/desktop/rpcs/auth_request.cc
@@ -23,6 +23,7 @@
 #include "app/src/heartbeat/heartbeat_controller_desktop.h"
 #include "app/src/include/firebase/app.h"
 #include "app/src/include/firebase/internal/mutex.h"
+#include "firebase/log.h"
 
 namespace firebase {
 namespace auth {
@@ -37,6 +38,8 @@ AuthRequest::AuthRequest(::firebase::App& app, const char* schema,
   // dependencies upon other parts of this library.  This complication is due to
   // the way the tests are currently configured where each library has minimal
   // dependencies.
+
+  CheckEmulator();
   static std::string auth_user_agent;           // NOLINT
   static std::string extended_auth_user_agent;  // NOLINT
   static Mutex* user_agent_mutex = new Mutex();
@@ -77,5 +80,40 @@ AuthRequest::AuthRequest(::firebase::App& app, const char* schema,
   }
 }
 
+std::string AuthRequest::GetUrl() {
+  if (emulator_url.empty()) {
+    std::string url(kHttps);
+    url += kServerURL;
+    return url;
+  } else {
+    std::string url(kHttp);
+    url += emulator_url;
+    url += kServerURL;
+    return url;
+  }
+}
+
+void AuthRequest::CheckEmulator() {
+  if (!emulator_url.empty()) {
+    LogDebug("Emulator Url already set: %s", emulator_url.c_str());
+    return;
+  }
+  // Use emulator as long as this env variable is set, regardless its value.
+  if (std::getenv("USE_AUTH_EMULATOR") == nullptr) {
+    LogDebug("Using Auth Prod for testing.");
+    return;
+  }
+
+  emulator_url.append(kEmulatorLocalHost);
+  emulator_url.append(":");
+  // Use AUTH_EMULATOR_PORT if it is set to non empty string,
+  // otherwise use the default port.
+  if (std::getenv("AUTH_EMULATOR_PORT") == nullptr) {
+    emulator_url.append(kEmulatorPort);
+  } else {
+    emulator_url.append(std::getenv("AUTH_EMULATOR_PORT"));
+  }
+}
+
 }  // namespace auth
 }  // namespace firebase
diff --git a/auth/src/desktop/rpcs/auth_request.h b/auth/src/desktop/rpcs/auth_request.h
index 670571e5a..88835e946 100644
--- a/auth/src/desktop/rpcs/auth_request.h
+++ b/auth/src/desktop/rpcs/auth_request.h
@@ -17,6 +17,8 @@
 #ifndef FIREBASE_AUTH_SRC_DESKTOP_RPCS_AUTH_REQUEST_H_
 #define FIREBASE_AUTH_SRC_DESKTOP_RPCS_AUTH_REQUEST_H_
 
+#include <string>
+
 #include "app/rest/request_json.h"
 #include "app/src/include/firebase/app.h"
 #include "auth/request_generated.h"
@@ -28,6 +30,16 @@ namespace auth {
 // Key name for header when sending language code data.
 extern const char* kHeaderFirebaseLocale;
 
+const char* const kHttps = "https://";
+
+const char* const kHttp = "http://";
+
+const char* const kServerURL =
+    "www.googleapis.com/identitytoolkit/v3/relyingparty/";
+
+const char* const kEmulatorLocalHost = "localhost";
+const char* const kEmulatorPort = "9099";
+
 class AuthRequest
     : public firebase::rest::RequestJson<fbs::Request, fbs::RequestT> {
  public:
@@ -39,6 +51,12 @@ class AuthRequest
               bool deliver_heartbeat)
       : AuthRequest(app, reinterpret_cast<const char*>(schema),
                     deliver_heartbeat) {}
+
+  std::string GetUrl();
+
+ private:
+  void CheckEmulator();
+  std::string emulator_url;
 };
 
 }  // namespace auth
diff --git a/auth/src/desktop/rpcs/create_auth_uri_request.cc b/auth/src/desktop/rpcs/create_auth_uri_request.cc
index 04ee9efc2..e0de666b4 100644
--- a/auth/src/desktop/rpcs/create_auth_uri_request.cc
+++ b/auth/src/desktop/rpcs/create_auth_uri_request.cc
@@ -14,6 +14,8 @@
 
 #include "auth/src/desktop/rpcs/create_auth_uri_request.h"
 
+#include <string>
+
 #include "app/src/assert.h"
 #include "app/src/include/firebase/app.h"
 #include "app/src/log.h"
@@ -27,11 +29,8 @@ CreateAuthUriRequest::CreateAuthUriRequest(::firebase::App& app,
     : AuthRequest(app, request_resource_data, true) {
   FIREBASE_ASSERT_RETURN_VOID(api_key);
 
-  const char api_host[] =
-      "https://www.googleapis.com/identitytoolkit/v3/relyingparty/"
-      "createAuthUri?key=";
-  std::string url;
-  url.reserve(strlen(api_host) + strlen(api_key));
+  const char api_host[] = "createAuthUri?key=";
+  std::string url = GetUrl();
   url.append(api_host);
   url.append(api_key);
   set_url(url.c_str());
diff --git a/auth/src/desktop/rpcs/delete_account_request.cc b/auth/src/desktop/rpcs/delete_account_request.cc
index efe393573..359fb0d74 100644
--- a/auth/src/desktop/rpcs/delete_account_request.cc
+++ b/auth/src/desktop/rpcs/delete_account_request.cc
@@ -14,6 +14,8 @@
 
 #include "auth/src/desktop/rpcs/delete_account_request.h"
 
+#include <string>
+
 #include "app/src/assert.h"
 #include "app/src/include/firebase/app.h"
 
@@ -25,11 +27,8 @@ DeleteAccountRequest::DeleteAccountRequest(::firebase::App& app,
     : AuthRequest(app, request_resource_data, true) {
   FIREBASE_ASSERT_RETURN_VOID(api_key);
 
-  const char api_host[] =
-      "https://www.googleapis.com/identitytoolkit/v3/relyingparty/"
-      "deleteAccount?key=";
-  std::string url;
-  url.reserve(strlen(api_host) + strlen(api_key));
+  const char api_host[] = "deleteAccount?key=";
+  std::string url = GetUrl();
   url.append(api_host);
   url.append(api_key);
   set_url(url.c_str());
diff --git a/auth/src/desktop/rpcs/get_account_info_request.cc b/auth/src/desktop/rpcs/get_account_info_request.cc
index 0dad730f1..e5f6cd4e7 100644
--- a/auth/src/desktop/rpcs/get_account_info_request.cc
+++ b/auth/src/desktop/rpcs/get_account_info_request.cc
@@ -14,6 +14,8 @@
 
 #include "auth/src/desktop/rpcs/get_account_info_request.h"
 
+#include <string>
+
 #include "app/src/assert.h"
 #include "app/src/include/firebase/app.h"
 
@@ -39,11 +41,8 @@ GetAccountInfoRequest::GetAccountInfoRequest(::firebase::App& app,
 void GetAccountInfoRequest::SetUrl(const char* const api_key) {
   FIREBASE_ASSERT_RETURN_VOID(api_key);
 
-  const char api_host[] =
-      "https://www.googleapis.com/identitytoolkit/v3/relyingparty/"
-      "getAccountInfo?key=";
-  std::string url;
-  url.reserve(strlen(api_host) + strlen(api_key));
+  const char api_host[] = "getAccountInfo?key=";
+  std::string url = GetUrl();
   url.append(api_host);
   url.append(api_key);
   set_url(url.c_str());
diff --git a/auth/src/desktop/rpcs/get_oob_confirmation_code_request.cc b/auth/src/desktop/rpcs/get_oob_confirmation_code_request.cc
index 3087837a6..3a1805884 100644
--- a/auth/src/desktop/rpcs/get_oob_confirmation_code_request.cc
+++ b/auth/src/desktop/rpcs/get_oob_confirmation_code_request.cc
@@ -14,6 +14,8 @@
 
 #include "auth/src/desktop/rpcs/get_oob_confirmation_code_request.h"
 
+#include <string>
+
 #include "app/src/assert.h"
 #include "app/src/include/firebase/app.h"
 
@@ -25,11 +27,8 @@ GetOobConfirmationCodeRequest::GetOobConfirmationCodeRequest(
     : AuthRequest(app, request_resource_data, true) {
   FIREBASE_ASSERT_RETURN_VOID(api_key);
 
-  const char api_host[] =
-      "https://www.googleapis.com/identitytoolkit/v3/relyingparty/"
-      "getOobConfirmationCode?key=";
-  std::string url;
-  url.reserve(strlen(api_host) + strlen(api_key));
+  const char api_host[] = "getOobConfirmationCode?key=";
+  std::string url = GetUrl();
   url.append(api_host);
   url.append(api_key);
   set_url(url.c_str());
diff --git a/auth/src/desktop/rpcs/reset_password_request.cc b/auth/src/desktop/rpcs/reset_password_request.cc
index b8fc65654..a8c64d1ff 100644
--- a/auth/src/desktop/rpcs/reset_password_request.cc
+++ b/auth/src/desktop/rpcs/reset_password_request.cc
@@ -14,6 +14,8 @@
 
 #include "auth/src/desktop/rpcs/reset_password_request.h"
 
+#include <string>
+
 #include "app/src/assert.h"
 #include "app/src/include/firebase/app.h"
 #include "app/src/log.h"
@@ -28,11 +30,8 @@ ResetPasswordRequest::ResetPasswordRequest(::firebase::App& app,
     : AuthRequest(app, request_resource_data, true) {
   FIREBASE_ASSERT_RETURN_VOID(api_key);
 
-  const char api_host[] =
-      "https://www.googleapis.com/identitytoolkit/v3/relyingparty/"
-      "resetPassword?key=";
-  std::string url;
-  url.reserve(strlen(api_host) + strlen(api_key));
+  const char api_host[] = "resetPassword?key=";
+  std::string url = GetUrl();
   url.append(api_host);
   url.append(api_key);
   set_url(url.c_str());
diff --git a/auth/src/desktop/rpcs/set_account_info_request.cc b/auth/src/desktop/rpcs/set_account_info_request.cc
index 48105661b..618cbef90 100644
--- a/auth/src/desktop/rpcs/set_account_info_request.cc
+++ b/auth/src/desktop/rpcs/set_account_info_request.cc
@@ -14,6 +14,8 @@
 
 #include "auth/src/desktop/rpcs/set_account_info_request.h"
 
+#include <string>
+
 #include "app/src/assert.h"
 #include "app/src/include/firebase/app.h"
 
@@ -25,11 +27,8 @@ SetAccountInfoRequest::SetAccountInfoRequest(::firebase::App& app,
     : AuthRequest(app, request_resource_data, true) {
   FIREBASE_ASSERT_RETURN_VOID(api_key);
 
-  const char api_host[] =
-      "https://www.googleapis.com/identitytoolkit/v3/relyingparty/"
-      "setAccountInfo?key=";
-  std::string url;
-  url.reserve(strlen(api_host) + strlen(api_key));
+  const char api_host[] = "setAccountInfo?key=";
+  std::string url = GetUrl();
   url.append(api_host);
   url.append(api_key);
   set_url(url.c_str());
diff --git a/auth/src/desktop/rpcs/sign_up_new_user_request.cc b/auth/src/desktop/rpcs/sign_up_new_user_request.cc
index 5a098b4b1..bd8d5ed09 100644
--- a/auth/src/desktop/rpcs/sign_up_new_user_request.cc
+++ b/auth/src/desktop/rpcs/sign_up_new_user_request.cc
@@ -14,6 +14,8 @@
 
 #include "auth/src/desktop/rpcs/sign_up_new_user_request.h"
 
+#include <string>
+
 #include "app/src/assert.h"
 #include "app/src/include/firebase/app.h"
 
@@ -53,11 +55,8 @@ SignUpNewUserRequest::SignUpNewUserRequest(::firebase::App& app,
 void SignUpNewUserRequest::SetUrl(const char* api_key) {
   FIREBASE_ASSERT_RETURN_VOID(api_key);
 
-  const char api_host[] =
-      "https://www.googleapis.com/identitytoolkit/v3/relyingparty/"
-      "signupNewUser?key=";
-  std::string url;
-  url.reserve(strlen(api_host) + strlen(api_key));
+  const char api_host[] = "signupNewUser?key=";
+  std::string url = GetUrl();
   url.append(api_host);
   url.append(api_key);
   set_url(url.c_str());
diff --git a/auth/src/desktop/rpcs/verify_assertion_request.cc b/auth/src/desktop/rpcs/verify_assertion_request.cc
index 84dc5e4f7..cca72d578 100644
--- a/auth/src/desktop/rpcs/verify_assertion_request.cc
+++ b/auth/src/desktop/rpcs/verify_assertion_request.cc
@@ -14,6 +14,8 @@
 
 #include "auth/src/desktop/rpcs/verify_assertion_request.h"
 
+#include <string>
+
 #include "app/src/assert.h"
 #include "app/src/include/firebase/app.h"
 
@@ -26,11 +28,8 @@ VerifyAssertionRequest::VerifyAssertionRequest(::firebase::App& app,
     : AuthRequest(app, request_resource_data, true) {
   FIREBASE_ASSERT_RETURN_VOID(api_key);
 
-  const char api_host[] =
-      "https://www.googleapis.com/identitytoolkit/v3/relyingparty/"
-      "verifyAssertion?key=";
-  std::string url;
-  url.reserve(strlen(api_host) + strlen(api_key));
+  const char api_host[] = "verifyAssertion?key=";
+  std::string url = GetUrl();
   url.append(api_host);
   url.append(api_key);
   set_url(url.c_str());
diff --git a/auth/src/desktop/rpcs/verify_custom_token_request.cc b/auth/src/desktop/rpcs/verify_custom_token_request.cc
index 83754219f..af53e6f3f 100644
--- a/auth/src/desktop/rpcs/verify_custom_token_request.cc
+++ b/auth/src/desktop/rpcs/verify_custom_token_request.cc
@@ -14,6 +14,8 @@
 
 #include "auth/src/desktop/rpcs/verify_custom_token_request.h"
 
+#include <string>
+
 #include "app/src/assert.h"
 #include "app/src/include/firebase/app.h"
 #include "app/src/log.h"
@@ -27,11 +29,8 @@ VerifyCustomTokenRequest::VerifyCustomTokenRequest(::firebase::App& app,
     : AuthRequest(app, request_resource_data, true) {
   FIREBASE_ASSERT_RETURN_VOID(api_key);
 
-  const char api_host[] =
-      "https://www.googleapis.com/identitytoolkit/v3/relyingparty/"
-      "verifyCustomToken?key=";
-  std::string url;
-  url.reserve(strlen(api_host) + strlen(api_key));
+  const char api_host[] = "verifyCustomToken?key=";
+  std::string url = GetUrl();
   url.append(api_host);
   url.append(api_key);
   set_url(url.c_str());
diff --git a/auth/src/desktop/rpcs/verify_password_request.cc b/auth/src/desktop/rpcs/verify_password_request.cc
index bbfddfa33..db840685a 100644
--- a/auth/src/desktop/rpcs/verify_password_request.cc
+++ b/auth/src/desktop/rpcs/verify_password_request.cc
@@ -14,6 +14,8 @@
 
 #include "auth/src/desktop/rpcs/verify_password_request.h"
 
+#include <string>
+
 #include "app/src/assert.h"
 #include "app/src/include/firebase/app.h"
 #include "app/src/log.h"
@@ -28,11 +30,8 @@ VerifyPasswordRequest::VerifyPasswordRequest(::firebase::App& app,
     : AuthRequest(app, request_resource_data, true) {
   FIREBASE_ASSERT_RETURN_VOID(api_key);
 
-  const char api_host[] =
-      "https://www.googleapis.com/identitytoolkit/v3/relyingparty/"
-      "verifyPassword?key=";
-  std::string url;
-  url.reserve(strlen(api_host) + strlen(api_key));
+  const char api_host[] = "verifyPassword?key=";
+  std::string url = GetUrl();
   url.append(api_host);
   url.append(api_key);
   set_url(url.c_str());
diff --git a/auth/src/include/firebase/auth.h b/auth/src/include/firebase/auth.h
index bec3ce8ff..f9c8bfbf3 100644
--- a/auth/src/include/firebase/auth.h
+++ b/auth/src/include/firebase/auth.h
@@ -17,6 +17,7 @@
 #ifndef FIREBASE_AUTH_SRC_INCLUDE_FIREBASE_AUTH_H_
 #define FIREBASE_AUTH_SRC_INCLUDE_FIREBASE_AUTH_H_
 
+#include <string>
 #include <vector>
 
 #include "firebase/app.h"
diff --git a/auth/src/ios/auth_ios.mm b/auth/src/ios/auth_ios.mm
index b8b52573a..e66af55dd 100644
--- a/auth/src/ios/auth_ios.mm
+++ b/auth/src/ios/auth_ios.mm
@@ -41,6 +41,9 @@ @implementation FIRCPPAuthListenerHandle
 namespace firebase {
 namespace auth {
 
+const char *const kEmulatorLocalHost = "localhost";
+const char *const kEmulatorPort = "9099";
+
 static const struct {
   int ios_error;
   AuthError cpp_error;
@@ -154,6 +157,24 @@ void UpdateCurrentUser(AuthData *auth_data) {
   SetUserImpl(auth_data, user);
 }
 
+void CheckEmulator(AuthData *auth_data) {
+  // Use emulator as long as this env variable is set, regardless its value.
+  if (std::getenv("USE_AUTH_EMULATOR") == nullptr) {
+    LogDebug("Using Auth Prod for testing.");
+    return;
+  }
+
+  // Use AUTH_EMULATOR_PORT if it is set to non empty string,
+  // otherwise use the default port.
+  uint32_t port = std::stoi(kEmulatorPort);
+  if (std::getenv("AUTH_EMULATOR_PORT") != nullptr) {
+    port = std::stoi(std::getenv("AUTH_EMULATOR_PORT"));
+  }
+
+  NSUInteger ns_port = port;
+  [AuthImpl(auth_data) useEmulatorWithHost:@(kEmulatorLocalHost) port:ns_port];
+}
+
 // Platform-specific method to initialize AuthData.
 void Auth::InitPlatformAuth(AuthData *auth_data) {
   FIRCPPAuthListenerHandle *listener_cpp_handle = [[FIRCPPAuthListenerHandle alloc] init];
@@ -191,6 +212,8 @@ void UpdateCurrentUser(AuthData *auth_data) {
   // It's possible for the user to be signed-in at creation, if the user signed-in during a
   // previous run, for example.
   UpdateCurrentUser(auth_data);
+
+  CheckEmulator(auth_data);
 }
 
 // Platform-specific method to destroy the wrapped Auth class.
diff --git a/release_build_files/readme.md b/release_build_files/readme.md
index 15827c0fb..788ce32f2 100644
--- a/release_build_files/readme.md
+++ b/release_build_files/readme.md
@@ -632,7 +632,10 @@ code.
     - General (Android): Update to Firebase Android BoM version 32.2.2.
     - General (iOS): Update to Firebase Cocoapods version 10.13.0.
     - General (iOS): 32-bit iOS builds (i386 and armv7) are no longer supported.
+    - General: Add FirebaseApp.GetApps(), to return the list of `firebase::App` instances.
     - GMA (Android): Fixed a crash when initializing GMA without a Firebase App.
+    - Firestore: Add support for disjunctions in queries (OR queries)
+      ([#1335](https://github.com/firebase/firebase-cpp-sdk/pull/1335)).
 
 ### 11.3.0
 -   Changes