diff --git a/packages/app/index.node.ts b/packages/app/index.node.ts
index 28128141aa4..560feb223ff 100644
--- a/packages/app/index.node.ts
+++ b/packages/app/index.node.ts
@@ -17,7 +17,7 @@
 
 import { FirebaseNamespace } from '@firebase/app-types';
 import { _FirebaseNamespace } from '@firebase/app-types/private';
-import { createFirebaseNamespace } from './src/firebaseApp';
+import { createFirebaseNamespace } from './src/firebaseNamespace';
 import Storage from 'dom-storage';
 import { XMLHttpRequest } from 'xmlhttprequest';
 
diff --git a/packages/app/index.rn.ts b/packages/app/index.rn.ts
index 3f0f3e2d0ac..fc8b85ef14b 100644
--- a/packages/app/index.rn.ts
+++ b/packages/app/index.rn.ts
@@ -17,7 +17,7 @@
 
 import { FirebaseNamespace } from '@firebase/app-types';
 import { _FirebaseNamespace } from '@firebase/app-types/private';
-import { createFirebaseNamespace } from './src/firebaseApp';
+import { createFirebaseNamespace } from './src/firebaseNamespace';
 
 /**
  * To avoid having to include the @types/react-native package, which breaks
diff --git a/packages/app/index.ts b/packages/app/index.ts
index e00fd6eefed..046059673ac 100644
--- a/packages/app/index.ts
+++ b/packages/app/index.ts
@@ -16,7 +16,7 @@
  */
 
 import { FirebaseNamespace } from '@firebase/app-types';
-import { createFirebaseNamespace } from './src/firebaseApp';
+import { createFirebaseNamespace } from './src/firebaseNamespace';
 
 // Node detection logic from: https://github.com/iliakan/detect-node/
 let isNode = false;
diff --git a/packages/app/src/errors.ts b/packages/app/src/errors.ts
new file mode 100644
index 00000000000..e6e229057d2
--- /dev/null
+++ b/packages/app/src/errors.ts
@@ -0,0 +1,47 @@
+/**
+ * @license
+ * Copyright 2019 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { ErrorFactory } from '@firebase/util';
+
+export const enum AppError {
+  NO_APP = 'no-app',
+  BAD_APP_NAME = 'bad-app-name',
+  DUPLICATE_APP = 'duplicate-app',
+  APP_DELETED = 'app-deleted',
+  DUPLICATE_SERVICE = 'duplicate-service',
+  INVALID_APP_ARGUMENT = 'invalid-app-argument'
+}
+
+const errors: { readonly [code in AppError]: string } = {
+  [AppError.NO_APP]:
+    "No Firebase App '{$name}' has been created - " +
+    'call Firebase App.initializeApp()',
+  [AppError.BAD_APP_NAME]: "Illegal App name: '{$name}",
+  [AppError.DUPLICATE_APP]: "Firebase App named '{$name}' already exists",
+  [AppError.APP_DELETED]: "Firebase App named '{$name}' already deleted",
+  [AppError.DUPLICATE_SERVICE]:
+    "Firebase service named '{$name}' already registered",
+  [AppError.INVALID_APP_ARGUMENT]:
+    'firebase.{$name}() takes either no argument or a ' +
+    'Firebase App instance.'
+};
+
+let appErrors = new ErrorFactory<AppError>('app', 'Firebase', errors);
+
+export function error(code: AppError, args?: { [name: string]: any }) {
+  throw appErrors.create(code, args);
+}
diff --git a/packages/app/src/firebaseApp.ts b/packages/app/src/firebaseApp.ts
index 6ff743cd170..968ed1ce7c0 100644
--- a/packages/app/src/firebaseApp.ts
+++ b/packages/app/src/firebaseApp.ts
@@ -24,27 +24,12 @@ import {
 import {
   _FirebaseApp,
   _FirebaseNamespace,
-  FirebaseService,
-  FirebaseServiceFactory,
-  FirebaseServiceNamespace,
-  AppHook
+  FirebaseService
 } from '@firebase/app-types/private';
-import {
-  createSubscribe,
-  deepCopy,
-  deepExtend,
-  ErrorFactory,
-  FirebaseError,
-  Observer,
-  patchProperty,
-  Subscribe
-} from '@firebase/util';
-
-const contains = function(obj, key) {
-  return Object.prototype.hasOwnProperty.call(obj, key);
-};
+import { deepCopy, deepExtend } from '@firebase/util';
+import { error, AppError } from './errors';
 
-const DEFAULT_ENTRY_NAME = '[DEFAULT]';
+export const DEFAULT_ENTRY_NAME = '[DEFAULT]';
 
 // An array to capture listeners before the true auth functions
 // exist
@@ -54,7 +39,7 @@ let tokenListeners: any[] = [];
  * Global context object for a collection of services using
  * a shared authentication state.
  */
-class FirebaseAppImpl implements FirebaseApp {
+export class FirebaseAppImpl implements FirebaseApp {
   private options_: FirebaseOptions;
   private name_: string;
   private isDeleted_ = false;
@@ -212,7 +197,7 @@ class FirebaseAppImpl implements FirebaseApp {
    */
   private checkDestroyed_(): void {
     if (this.isDeleted_) {
-      error('app-deleted', { name: this.name_ });
+      error(AppError.APP_DELETED, { name: this.name_ });
     }
   }
 }
@@ -222,262 +207,3 @@ class FirebaseAppImpl implements FirebaseApp {
 (FirebaseAppImpl.prototype.name && FirebaseAppImpl.prototype.options) ||
   FirebaseAppImpl.prototype.delete ||
   console.log('dc');
-
-/**
- * Return a firebase namespace object.
- *
- * In production, this will be called exactly once and the result
- * assigned to the 'firebase' global.  It may be called multiple times
- * in unit tests.
- */
-export function createFirebaseNamespace(): FirebaseNamespace {
-  let apps_: { [name: string]: FirebaseApp } = {};
-  let factories: { [service: string]: FirebaseServiceFactory } = {};
-  let appHooks: { [service: string]: AppHook } = {};
-
-  // A namespace is a plain JavaScript Object.
-  let namespace = {
-    // Hack to prevent Babel from modifying the object returned
-    // as the firebase namespace.
-    __esModule: true,
-    initializeApp: initializeApp,
-    app: app as any,
-    apps: null as any,
-    Promise: Promise,
-    SDK_VERSION: '${JSCORE_VERSION}',
-    INTERNAL: {
-      registerService: registerService,
-      createFirebaseNamespace: createFirebaseNamespace,
-      extendNamespace: extendNamespace,
-      createSubscribe: createSubscribe,
-      ErrorFactory: ErrorFactory,
-      removeApp: removeApp,
-      factories: factories,
-      useAsService: useAsService,
-      Promise: Promise,
-      deepExtend: deepExtend
-    }
-  };
-
-  // Inject a circular default export to allow Babel users who were previously
-  // using:
-  //
-  //   import firebase from 'firebase';
-  //   which becomes: var firebase = require('firebase').default;
-  //
-  // instead of
-  //
-  //   import * as firebase from 'firebase';
-  //   which becomes: var firebase = require('firebase');
-  patchProperty(namespace, 'default', namespace);
-
-  // firebase.apps is a read-only getter.
-  Object.defineProperty(namespace, 'apps', {
-    get: getApps
-  });
-
-  /**
-   * Called by App.delete() - but before any services associated with the App
-   * are deleted.
-   */
-  function removeApp(name: string): void {
-    let app = apps_[name];
-    callAppHooks(app, 'delete');
-    delete apps_[name];
-  }
-
-  /**
-   * Get the App object for a given name (or DEFAULT).
-   */
-  function app(name?: string): FirebaseApp {
-    name = name || DEFAULT_ENTRY_NAME;
-    if (!contains(apps_, name)) {
-      error('no-app', { name: name });
-    }
-    return apps_[name];
-  }
-
-  patchProperty(app, 'App', FirebaseAppImpl);
-
-  /**
-   * Create a new App instance (name must be unique).
-   */
-  function initializeApp(
-    options: FirebaseOptions,
-    config?: FirebaseAppConfig
-  ): FirebaseApp;
-  function initializeApp(options: FirebaseOptions, name?: string): FirebaseApp;
-  function initializeApp(options: FirebaseOptions, rawConfig = {}) {
-    if (typeof rawConfig !== 'object' || rawConfig === null) {
-      const name = rawConfig;
-      rawConfig = { name };
-    }
-
-    const config = rawConfig as FirebaseAppConfig;
-
-    if (config.name === undefined) {
-      config.name = DEFAULT_ENTRY_NAME;
-    }
-
-    const { name } = config;
-
-    if (typeof name !== 'string' || !name) {
-      error('bad-app-name', { name: name + '' });
-    }
-
-    if (contains(apps_, name)) {
-      error('duplicate-app', { name: name });
-    }
-
-    let app = new FirebaseAppImpl(
-      options,
-      config!,
-      namespace as FirebaseNamespace
-    );
-
-    apps_[name!] = app;
-    callAppHooks(app, 'create');
-
-    return app;
-  }
-
-  /*
-   * Return an array of all the non-deleted FirebaseApps.
-   */
-  function getApps(): FirebaseApp[] {
-    // Make a copy so caller cannot mutate the apps list.
-    return Object.keys(apps_).map(name => apps_[name]);
-  }
-
-  /*
-   * Register a Firebase Service.
-   *
-   * firebase.INTERNAL.registerService()
-   *
-   * TODO: Implement serviceProperties.
-   */
-  function registerService(
-    name: string,
-    createService: FirebaseServiceFactory,
-    serviceProperties?: { [prop: string]: any },
-    appHook?: AppHook,
-    allowMultipleInstances?: boolean
-  ): FirebaseServiceNamespace<FirebaseService> {
-    // Cannot re-register a service that already exists
-    if (factories[name]) {
-      error('duplicate-service', { name: name });
-    }
-
-    // Capture the service factory for later service instantiation
-    factories[name] = createService;
-
-    // Capture the appHook, if passed
-    if (appHook) {
-      appHooks[name] = appHook;
-
-      // Run the **new** app hook on all existing apps
-      getApps().forEach(app => {
-        appHook('create', app);
-      });
-    }
-
-    // The Service namespace is an accessor function ...
-    const serviceNamespace = (appArg: FirebaseApp = app()) => {
-      if (typeof (appArg as any)[name] !== 'function') {
-        // Invalid argument.
-        // This happens in the following case: firebase.storage('gs:/')
-        error('invalid-app-argument', { name: name });
-      }
-
-      // Forward service instance lookup to the FirebaseApp.
-      return (appArg as any)[name]();
-    };
-
-    // ... and a container for service-level properties.
-    if (serviceProperties !== undefined) {
-      deepExtend(serviceNamespace, serviceProperties);
-    }
-
-    // Monkey-patch the serviceNamespace onto the firebase namespace
-    (namespace as any)[name] = serviceNamespace;
-
-    // Patch the FirebaseAppImpl prototype
-    FirebaseAppImpl.prototype[name] = function(...args) {
-      const serviceFxn = this._getService.bind(this, name);
-      return serviceFxn.apply(this, allowMultipleInstances ? args : []);
-    };
-
-    return serviceNamespace;
-  }
-
-  /**
-   * Patch the top-level firebase namespace with additional properties.
-   *
-   * firebase.INTERNAL.extendNamespace()
-   */
-  function extendNamespace(props: { [prop: string]: any }): void {
-    deepExtend(namespace, props);
-  }
-
-  function callAppHooks(app: FirebaseApp, eventName: string) {
-    Object.keys(factories).forEach(serviceName => {
-      // Ignore virtual services
-      let factoryName = useAsService(app, serviceName);
-      if (factoryName === null) {
-        return;
-      }
-
-      if (appHooks[factoryName]) {
-        appHooks[factoryName](eventName, app);
-      }
-    });
-  }
-
-  // Map the requested service to a registered service name
-  // (used to map auth to serverAuth service when needed).
-  function useAsService(app: FirebaseApp, name: string): string | null {
-    if (name === 'serverAuth') {
-      return null;
-    }
-
-    let useService = name;
-    let options = app.options;
-
-    return useService;
-  }
-
-  return (namespace as any) as FirebaseNamespace;
-}
-
-type AppError =
-  | 'no-app'
-  | 'bad-app-name'
-  | 'duplicate-app'
-  | 'app-deleted'
-  | 'duplicate-service'
-  | 'sa-not-supported'
-  | 'invalid-app-argument';
-
-function error(code: AppError, args?: { [name: string]: any }) {
-  throw appErrors.create(code, args);
-}
-
-const errors: { readonly [code in AppError]: string } = {
-  'no-app':
-    "No Firebase App '{$name}' has been created - " +
-    'call Firebase App.initializeApp()',
-  'bad-app-name': "Illegal App name: '{$name}",
-  'duplicate-app': "Firebase App named '{$name}' already exists",
-  'app-deleted': "Firebase App named '{$name}' already deleted",
-  'duplicate-service': "Firebase service named '{$name}' already registered",
-  'sa-not-supported':
-    'Initializing the Firebase SDK with a service ' +
-    'account is only allowed in a Node.js environment. On client ' +
-    'devices, you should instead initialize the SDK with an api key and ' +
-    'auth domain',
-  'invalid-app-argument':
-    'firebase.{$name}() takes either no argument or a ' +
-    'Firebase App instance.'
-};
-
-let appErrors = new ErrorFactory<AppError>('app', 'Firebase', errors);
diff --git a/packages/app/src/firebaseNamespace.ts b/packages/app/src/firebaseNamespace.ts
new file mode 100644
index 00000000000..06c89ee3cfb
--- /dev/null
+++ b/packages/app/src/firebaseNamespace.ts
@@ -0,0 +1,269 @@
+/**
+ * @license
+ * Copyright 2019 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import {
+  FirebaseApp,
+  FirebaseOptions,
+  FirebaseNamespace,
+  FirebaseAppConfig
+} from '@firebase/app-types';
+import {
+  _FirebaseApp,
+  _FirebaseNamespace,
+  FirebaseService,
+  FirebaseServiceFactory,
+  FirebaseServiceNamespace,
+  AppHook
+} from '@firebase/app-types/private';
+import {
+  createSubscribe,
+  deepExtend,
+  ErrorFactory,
+  patchProperty
+} from '@firebase/util';
+import { FirebaseAppImpl, DEFAULT_ENTRY_NAME } from './firebaseApp';
+import { error, AppError } from './errors';
+
+const contains = function(obj, key) {
+  return Object.prototype.hasOwnProperty.call(obj, key);
+};
+
+/**
+ * Return a firebase namespace object.
+ *
+ * In production, this will be called exactly once and the result
+ * assigned to the 'firebase' global.  It may be called multiple times
+ * in unit tests.
+ */
+export function createFirebaseNamespace(): FirebaseNamespace {
+  let apps_: { [name: string]: FirebaseApp } = {};
+  let factories: { [service: string]: FirebaseServiceFactory } = {};
+  let appHooks: { [service: string]: AppHook } = {};
+
+  // A namespace is a plain JavaScript Object.
+  let namespace = {
+    // Hack to prevent Babel from modifying the object returned
+    // as the firebase namespace.
+    __esModule: true,
+    initializeApp: initializeApp,
+    app: app as any,
+    apps: null as any,
+    Promise: Promise,
+    SDK_VERSION: '${JSCORE_VERSION}',
+    INTERNAL: {
+      registerService: registerService,
+      createFirebaseNamespace: createFirebaseNamespace,
+      extendNamespace: extendNamespace,
+      createSubscribe: createSubscribe,
+      ErrorFactory: ErrorFactory,
+      removeApp: removeApp,
+      factories: factories,
+      useAsService: useAsService,
+      Promise: Promise,
+      deepExtend: deepExtend
+    }
+  };
+
+  // Inject a circular default export to allow Babel users who were previously
+  // using:
+  //
+  //   import firebase from 'firebase';
+  //   which becomes: var firebase = require('firebase').default;
+  //
+  // instead of
+  //
+  //   import * as firebase from 'firebase';
+  //   which becomes: var firebase = require('firebase');
+  patchProperty(namespace, 'default', namespace);
+
+  // firebase.apps is a read-only getter.
+  Object.defineProperty(namespace, 'apps', {
+    get: getApps
+  });
+
+  /**
+   * Called by App.delete() - but before any services associated with the App
+   * are deleted.
+   */
+  function removeApp(name: string): void {
+    let app = apps_[name];
+    callAppHooks(app, 'delete');
+    delete apps_[name];
+  }
+
+  /**
+   * Get the App object for a given name (or DEFAULT).
+   */
+  function app(name?: string): FirebaseApp {
+    name = name || DEFAULT_ENTRY_NAME;
+    if (!contains(apps_, name)) {
+      error(AppError.NO_APP, { name: name });
+    }
+    return apps_[name];
+  }
+
+  patchProperty(app, 'App', FirebaseAppImpl);
+
+  /**
+   * Create a new App instance (name must be unique).
+   */
+  function initializeApp(
+    options: FirebaseOptions,
+    config?: FirebaseAppConfig
+  ): FirebaseApp;
+  function initializeApp(options: FirebaseOptions, name?: string): FirebaseApp;
+  function initializeApp(options: FirebaseOptions, rawConfig = {}) {
+    if (typeof rawConfig !== 'object' || rawConfig === null) {
+      const name = rawConfig;
+      rawConfig = { name };
+    }
+
+    const config = rawConfig as FirebaseAppConfig;
+
+    if (config.name === undefined) {
+      config.name = DEFAULT_ENTRY_NAME;
+    }
+
+    const { name } = config;
+
+    if (typeof name !== 'string' || !name) {
+      error(AppError.BAD_APP_NAME, { name: name + '' });
+    }
+
+    if (contains(apps_, name)) {
+      error(AppError.DUPLICATE_APP, { name: name });
+    }
+
+    let app = new FirebaseAppImpl(
+      options,
+      config!,
+      namespace as FirebaseNamespace
+    );
+
+    apps_[name!] = app;
+    callAppHooks(app, 'create');
+
+    return app;
+  }
+
+  /*
+   * Return an array of all the non-deleted FirebaseApps.
+   */
+  function getApps(): FirebaseApp[] {
+    // Make a copy so caller cannot mutate the apps list.
+    return Object.keys(apps_).map(name => apps_[name]);
+  }
+
+  /*
+   * Register a Firebase Service.
+   *
+   * firebase.INTERNAL.registerService()
+   *
+   * TODO: Implement serviceProperties.
+   */
+  function registerService(
+    name: string,
+    createService: FirebaseServiceFactory,
+    serviceProperties?: { [prop: string]: any },
+    appHook?: AppHook,
+    allowMultipleInstances?: boolean
+  ): FirebaseServiceNamespace<FirebaseService> {
+    // Cannot re-register a service that already exists
+    if (factories[name]) {
+      error(AppError.DUPLICATE_SERVICE, { name: name });
+    }
+
+    // Capture the service factory for later service instantiation
+    factories[name] = createService;
+
+    // Capture the appHook, if passed
+    if (appHook) {
+      appHooks[name] = appHook;
+
+      // Run the **new** app hook on all existing apps
+      getApps().forEach(app => {
+        appHook('create', app);
+      });
+    }
+
+    // The Service namespace is an accessor function ...
+    const serviceNamespace = (appArg: FirebaseApp = app()) => {
+      if (typeof (appArg as any)[name] !== 'function') {
+        // Invalid argument.
+        // This happens in the following case: firebase.storage('gs:/')
+        error(AppError.INVALID_APP_ARGUMENT, { name: name });
+      }
+
+      // Forward service instance lookup to the FirebaseApp.
+      return (appArg as any)[name]();
+    };
+
+    // ... and a container for service-level properties.
+    if (serviceProperties !== undefined) {
+      deepExtend(serviceNamespace, serviceProperties);
+    }
+
+    // Monkey-patch the serviceNamespace onto the firebase namespace
+    (namespace as any)[name] = serviceNamespace;
+
+    // Patch the FirebaseAppImpl prototype
+    FirebaseAppImpl.prototype[name] = function(...args) {
+      const serviceFxn = this._getService.bind(this, name);
+      return serviceFxn.apply(this, allowMultipleInstances ? args : []);
+    };
+
+    return serviceNamespace;
+  }
+
+  /**
+   * Patch the top-level firebase namespace with additional properties.
+   *
+   * firebase.INTERNAL.extendNamespace()
+   */
+  function extendNamespace(props: { [prop: string]: any }): void {
+    deepExtend(namespace, props);
+  }
+
+  function callAppHooks(app: FirebaseApp, eventName: string) {
+    Object.keys(factories).forEach(serviceName => {
+      // Ignore virtual services
+      let factoryName = useAsService(app, serviceName);
+      if (factoryName === null) {
+        return;
+      }
+
+      if (appHooks[factoryName]) {
+        appHooks[factoryName](eventName, app);
+      }
+    });
+  }
+
+  // Map the requested service to a registered service name
+  // (used to map auth to serverAuth service when needed).
+  function useAsService(app: FirebaseApp, name: string): string | null {
+    if (name === 'serverAuth') {
+      return null;
+    }
+
+    let useService = name;
+    let options = app.options;
+
+    return useService;
+  }
+
+  return (namespace as any) as FirebaseNamespace;
+}
diff --git a/packages/app/test/firebaseApp.test.ts b/packages/app/test/firebaseApp.test.ts
index 9a9d15ce982..8d20221e620 100644
--- a/packages/app/test/firebaseApp.test.ts
+++ b/packages/app/test/firebaseApp.test.ts
@@ -21,7 +21,7 @@ import {
   _FirebaseNamespace,
   FirebaseService
 } from '@firebase/app-types/private';
-import { createFirebaseNamespace } from '../src/firebaseApp';
+import { createFirebaseNamespace } from '../src/firebaseNamespace';
 import { assert } from 'chai';
 
 describe('Firebase App Class', () => {