diff --git a/lib/firebase.js b/lib/firebase.js
index bbddff42..810957d6 100644
--- a/lib/firebase.js
+++ b/lib/firebase.js
@@ -35,6 +35,17 @@ class FirebaseCore {
       INTERNALS.APPS[app.name] = new FirebaseApp(app.name, options);
       INTERNALS.APPS[app.name]._initializeApp(true);
     }
+
+    // modules
+    this.admob = this._appNamespaceOrStatics('admob', AdMobStatics, AdMob);
+    this.auth = this._appNamespaceOrStatics('auth', AuthStatics, Auth);
+    this.analytics = this._appNamespaceOrStatics('analytics', {}, Analytics);
+    this.config = this._appNamespaceOrStatics('config', {}, RemoteConfig);
+    this.crash = this._appNamespaceOrStatics('crash', {}, Crash);
+    this.database = this._appNamespaceOrStatics('database', DatabaseStatics, Database);
+    this.messaging = this._appNamespaceOrStatics('messaging', MessagingStatics, Messaging);
+    this.perf = this._appNamespaceOrStatics('perf', DatabaseStatics, Performance);
+    this.storage = this._appNamespaceOrStatics('storage', StorageStatics, Storage);
   }
 
   /**
@@ -45,33 +56,50 @@ class FirebaseCore {
    * @return {*}
    */
   initializeApp(options: Object = {}, name: string): FirebaseApp {
-    if (!isObject(options)) {
-      throw new Error(INTERNALS.STRINGS.ERROR_INIT_OBJECT);
-    }
-
-    // todo validate required options
-    // todo required:
-    /*
-     appProps.put("apiKey", appOptions.getApiKey());
-     appProps.put("applicationId", appOptions.getApplicationId());
-     appProps.put("databaseUrl", appOptions.getDatabaseUrl());
-     appProps.put("messagingSenderId", appOptions.getGcmSenderId());
-     appProps.put("projectId", appOptions.getProjectId());
-     appProps.put("storageBucket", appOptions.getStorageBucket());
-    */
-
     if (name && !isString(name)) {
       throw new Error(INTERNALS.STRINGS.ERROR_INIT_STRING_NAME);
     }
 
     const _name = (name || INTERNALS.STRINGS.DEFAULT_APP_NAME).toUpperCase();
 
-    if (!INTERNALS.APPS[_name]) {
-      INTERNALS.APPS[_name] = new FirebaseApp(_name, options);
-      // only initialize if certain props are available
-      if (options.databaseURL && options.apiKey) {
-        INTERNALS.APPS[_name]._initializeApp();
-      }
+    // return an existing app if found
+    if (INTERNALS.APPS[_name]) return INTERNALS.APPS[_name];
+
+    // only validate if app doesn't already exist
+    // to allow apps already initialized natively
+    // to still go through init without erroring (backwards compatibility)
+    if (!isObject(options)) {
+      throw new Error(INTERNALS.STRINGS.ERROR_INIT_OBJECT);
+    }
+
+    if (!options.apiKey) {
+      throw new Error(INTERNALS.STRINGS.ERROR_MISSING_OPT('apiKey'));
+    }
+
+    if (!options.appId) {
+      throw new Error(INTERNALS.STRINGS.ERROR_MISSING_OPT('appId'));
+    }
+
+    if (!options.databaseURL) {
+      throw new Error(INTERNALS.STRINGS.ERROR_MISSING_OPT('databaseURL'));
+    }
+
+    if (!options.messagingSenderId) {
+      throw new Error(INTERNALS.STRINGS.ERROR_MISSING_OPT('messagingSenderId'));
+    }
+
+    if (!options.projectId) {
+      throw new Error(INTERNALS.STRINGS.ERROR_MISSING_OPT('projectId'));
+    }
+
+    if (!options.storageBucket) {
+      throw new Error(INTERNALS.STRINGS.ERROR_MISSING_OPT('storageBucket'));
+    }
+
+    INTERNALS.APPS[_name] = new FirebaseApp(_name, options);
+    // only initialize if certain props are available
+    if (options.databaseURL && options.apiKey) {
+      INTERNALS.APPS[_name]._initializeApp();
     }
 
     return INTERNALS.APPS[_name];
@@ -108,6 +136,13 @@ class FirebaseCore {
     return PACKAGE.version;
   }
 
+  /**
+   * The platform specific default app name
+   */
+  get DEFAULT_APP_NAME() {
+    return INTERNALS.STRINGS.DEFAULT_APP_NAME;
+  }
+
   /**
    * Returns props from the android GoogleApiAvailability sdk
    * @android
@@ -117,52 +152,9 @@ class FirebaseCore {
     return FirebaseCoreModule.googleApiAvailability || { isAvailable: true, status: 0 };
   }
 
-  /*
-   * MODULES
-   */
-
-  get admob() {
-    return this._appNamespaceOrStatics('admob', AdMobStatics, AdMob);
-  }
-
-  get auth() {
-    return this._appNamespaceOrStatics('auth', AuthStatics, Auth);
-  }
-
-  get analytics() {
-    return this._appNamespaceOrStatics('analytics', {}, Analytics);
-  }
-
-  get config() {
-    return this._appNamespaceOrStatics('config', {}, RemoteConfig);
-  }
-
-  get crash() {
-    return this._appNamespaceOrStatics('crash', {}, Crash);
-  }
-
-
-  get database() {
-    return this._appNamespaceOrStatics('database', DatabaseStatics, Database);
-  }
-
-  get messaging() {
-    return this._appNamespaceOrStatics('messaging', MessagingStatics, Messaging);
-  }
-
-  get perf() {
-    return this._appNamespaceOrStatics('perf', DatabaseStatics, Performance);
-  }
-
-  get storage() {
-    return this._appNamespaceOrStatics('storage', StorageStatics, Storage);
-  }
-
-
   /*
    * CONFIG METHODS
    */
-
   /**
    * Set the global logging level for all logs.
    *
diff --git a/lib/internals.js b/lib/internals.js
index 02a96dbe..088c6648 100644
--- a/lib/internals.js
+++ b/lib/internals.js
@@ -33,6 +33,15 @@ export default {
       return `The [${appName}] firebase app has not been initialized!`;
     },
 
+    /**
+     * @param optName
+     * @return {string}
+     * @constructor
+     */
+    ERROR_MISSING_OPT(optName) {
+      return `Failed to initialize app. FirebaseOptions missing or invalid '${optName}' property.`;
+    },
+
     /**
      * @return {string}
      */
diff --git a/lib/modules/storage/index.js b/lib/modules/storage/index.js
index 1718bfd6..5cc4fb0a 100644
--- a/lib/modules/storage/index.js
+++ b/lib/modules/storage/index.js
@@ -3,7 +3,6 @@ import { NativeModules } from 'react-native';
 
 import StorageRef from './reference';
 import ModuleBase from './../../utils/ModuleBase';
-import INTERNALS from './../../internals';
 
 const FirebaseStorage = NativeModules.RNFirebaseStorage;
 
diff --git a/lib/utils/ModuleBase.js b/lib/utils/ModuleBase.js
index 9759733d..25f51be5 100644
--- a/lib/utils/ModuleBase.js
+++ b/lib/utils/ModuleBase.js
@@ -27,6 +27,13 @@ const NATIVE_MODULE_EVENTS = {
 };
 
 export default class ModuleBase {
+  /**
+   *
+   * @param firebaseApp
+   * @param options
+   * @param moduleName
+   * @param withEventEmitter
+   */
   constructor(firebaseApp, options, moduleName, withEventEmitter = false) {
     this._options = Object.assign({}, options);
     this._module = moduleName;
@@ -62,7 +69,7 @@ export default class ModuleBase {
    * @private
    */
   _setupEventEmitter(nativeModule, moduleName) {
-    this._eventEmitter = FirebaseCore._getOrSetNativeEmitter(this._appName, nativeModule);
+    this._eventEmitter = FirebaseCore._getOrSetNativeEmitter(`${this._appName}-${this._module}`, nativeModule);
     const events = NATIVE_MODULE_EVENTS[moduleName];
 
     if (events && events.length) {