diff --git a/src/modules/admob/index.js b/src/modules/admob/index.js
index 8b2e039d..a1ae8c37 100644
--- a/src/modules/admob/index.js
+++ b/src/modules/admob/index.js
@@ -41,8 +41,8 @@ export default class AdMob extends ModuleBase {
     super(app, {
       events: NATIVE_EVENTS,
       moduleName: MODULE_NAME,
-      multiApp: false,
-      hasShards: false,
+      hasMultiAppSupport: false,
+      hasCustomUrlSupport: false,
       namespace: NAMESPACE,
     });
 
diff --git a/src/modules/analytics/index.js b/src/modules/analytics/index.js
index 7e1af364..007e1c7c 100644
--- a/src/modules/analytics/index.js
+++ b/src/modules/analytics/index.js
@@ -33,8 +33,8 @@ export default class Analytics extends ModuleBase {
   constructor(app: App) {
     super(app, {
       moduleName: MODULE_NAME,
-      multiApp: false,
-      hasShards: false,
+      hasMultiAppSupport: false,
+      hasCustomUrlSupport: false,
       namespace: NAMESPACE,
     });
   }
diff --git a/src/modules/auth/index.js b/src/modules/auth/index.js
index c3528cf6..cd80de13 100644
--- a/src/modules/auth/index.js
+++ b/src/modules/auth/index.js
@@ -55,8 +55,8 @@ export default class Auth extends ModuleBase {
     super(app, {
       events: NATIVE_EVENTS,
       moduleName: MODULE_NAME,
-      multiApp: true,
-      hasShards: false,
+      hasMultiAppSupport: true,
+      hasCustomUrlSupport: false,
       namespace: NAMESPACE,
     });
     this._user = null;
diff --git a/src/modules/config/index.js b/src/modules/config/index.js
index aa5e8a42..97efdb12 100644
--- a/src/modules/config/index.js
+++ b/src/modules/config/index.js
@@ -36,8 +36,8 @@ export default class RemoteConfig extends ModuleBase {
   constructor(app: App) {
     super(app, {
       moduleName: MODULE_NAME,
-      multiApp: false,
-      hasShards: false,
+      hasMultiAppSupport: false,
+      hasCustomUrlSupport: false,
       namespace: NAMESPACE,
     });
     this._developerModeEnabled = false;
diff --git a/src/modules/crashlytics/index.js b/src/modules/crashlytics/index.js
index 0f97a144..77c25705 100644
--- a/src/modules/crashlytics/index.js
+++ b/src/modules/crashlytics/index.js
@@ -14,8 +14,8 @@ export default class Crashlytics extends ModuleBase {
   constructor(app: App) {
     super(app, {
       moduleName: MODULE_NAME,
-      multiApp: false,
-      hasShards: false,
+      hasMultiAppSupport: false,
+      hasCustomUrlSupport: false,
       namespace: NAMESPACE,
     });
   }
diff --git a/src/modules/database/index.js b/src/modules/database/index.js
index fb86f3b6..38807c66 100644
--- a/src/modules/database/index.js
+++ b/src/modules/database/index.js
@@ -48,8 +48,8 @@ export default class Database extends ModuleBase {
       {
         events: NATIVE_EVENTS,
         moduleName: MODULE_NAME,
-        multiApp: true,
-        hasShards: true,
+        hasMultiAppSupport: true,
+        hasCustomUrlSupport: true,
         namespace: NAMESPACE,
       },
       serviceUrl
diff --git a/src/modules/firestore/index.js b/src/modules/firestore/index.js
index 7d336159..efbdc5c4 100644
--- a/src/modules/firestore/index.js
+++ b/src/modules/firestore/index.js
@@ -69,8 +69,8 @@ export default class Firestore extends ModuleBase {
     super(app, {
       events: NATIVE_EVENTS,
       moduleName: MODULE_NAME,
-      multiApp: true,
-      hasShards: false,
+      hasMultiAppSupport: true,
+      hasCustomUrlSupport: false,
       namespace: NAMESPACE,
     });
 
diff --git a/src/modules/iid/index.js b/src/modules/iid/index.js
index 773fb033..f6ce3a85 100644
--- a/src/modules/iid/index.js
+++ b/src/modules/iid/index.js
@@ -13,9 +13,9 @@ export const MODULE_NAME = 'RNFirebaseInstanceId';
 export default class InstanceId extends ModuleBase {
   constructor(app: App) {
     super(app, {
-      hasShards: false,
+      hasCustomUrlSupport: false,
       moduleName: MODULE_NAME,
-      multiApp: false,
+      hasMultiAppSupport: false,
       namespace: NAMESPACE,
     });
   }
diff --git a/src/modules/invites/index.js b/src/modules/invites/index.js
index 31f81df9..d253762d 100644
--- a/src/modules/invites/index.js
+++ b/src/modules/invites/index.js
@@ -24,9 +24,9 @@ export default class Invites extends ModuleBase {
   constructor(app: App) {
     super(app, {
       events: NATIVE_EVENTS,
-      hasShards: false,
+      hasCustomUrlSupport: false,
       moduleName: MODULE_NAME,
-      multiApp: false,
+      hasMultiAppSupport: false,
       namespace: NAMESPACE,
     });
 
diff --git a/src/modules/links/index.js b/src/modules/links/index.js
index 5fca4884..cfbb55f5 100644
--- a/src/modules/links/index.js
+++ b/src/modules/links/index.js
@@ -24,8 +24,8 @@ export default class Links extends ModuleBase {
     super(app, {
       events: NATIVE_EVENTS,
       moduleName: MODULE_NAME,
-      multiApp: false,
-      hasShards: false,
+      hasMultiAppSupport: false,
+      hasCustomUrlSupport: false,
       namespace: NAMESPACE,
     });
 
diff --git a/src/modules/messaging/index.js b/src/modules/messaging/index.js
index 52aad936..847ed664 100644
--- a/src/modules/messaging/index.js
+++ b/src/modules/messaging/index.js
@@ -42,8 +42,8 @@ export default class Messaging extends ModuleBase {
     super(app, {
       events: NATIVE_EVENTS,
       moduleName: MODULE_NAME,
-      multiApp: false,
-      hasShards: false,
+      hasMultiAppSupport: false,
+      hasCustomUrlSupport: false,
       namespace: NAMESPACE,
     });
 
diff --git a/src/modules/notifications/index.js b/src/modules/notifications/index.js
index b42d3d65..ec0ae608 100644
--- a/src/modules/notifications/index.js
+++ b/src/modules/notifications/index.js
@@ -77,9 +77,9 @@ export default class Notifications extends ModuleBase {
   constructor(app: App) {
     super(app, {
       events: NATIVE_EVENTS,
-      hasShards: false,
+      hasCustomUrlSupport: false,
       moduleName: MODULE_NAME,
-      multiApp: false,
+      hasMultiAppSupport: false,
       namespace: NAMESPACE,
     });
     this._android = new AndroidNotifications(this);
diff --git a/src/modules/perf/index.js b/src/modules/perf/index.js
index a7a25ad7..bb3dc2a4 100644
--- a/src/modules/perf/index.js
+++ b/src/modules/perf/index.js
@@ -39,8 +39,8 @@ export default class PerformanceMonitoring extends ModuleBase {
   constructor(app: App) {
     super(app, {
       moduleName: MODULE_NAME,
-      multiApp: false,
-      hasShards: false,
+      hasMultiAppSupport: false,
+      hasCustomUrlSupport: false,
       namespace: NAMESPACE,
     });
   }
diff --git a/src/modules/storage/index.js b/src/modules/storage/index.js
index 468ed029..08216090 100644
--- a/src/modules/storage/index.js
+++ b/src/modules/storage/index.js
@@ -30,8 +30,8 @@ export default class Storage extends ModuleBase {
     super(app, {
       events: NATIVE_EVENTS,
       moduleName: MODULE_NAME,
-      multiApp: true,
-      hasShards: false,
+      hasMultiAppSupport: true,
+      hasCustomUrlSupport: false,
       namespace: NAMESPACE,
     });
 
diff --git a/src/modules/utils/index.js b/src/modules/utils/index.js
index fdb77ae2..2e6f2921 100644
--- a/src/modules/utils/index.js
+++ b/src/modules/utils/index.js
@@ -22,8 +22,8 @@ export default class RNFirebaseUtils extends ModuleBase {
   constructor(app: App) {
     super(app, {
       moduleName: MODULE_NAME,
-      multiApp: false,
-      hasShards: false,
+      hasMultiAppSupport: false,
+      hasCustomUrlSupport: false,
       namespace: NAMESPACE,
     });
   }
diff --git a/src/types/index.js b/src/types/index.js
index 758f4a15..e2b233ce 100644
--- a/src/types/index.js
+++ b/src/types/index.js
@@ -49,8 +49,9 @@ export type FirebaseModule = $Subtype<ModuleBase>;
 export type FirebaseModuleConfig = {
   events?: string[],
   moduleName: FirebaseModuleName,
-  multiApp: boolean,
-  hasShards: boolean,
+  hasMultiAppSupport: boolean,
+  hasCustomUrlSupport: boolean,
+  hasRegionsSupport: boolean,
   namespace: FirebaseNamespace,
 };
 
diff --git a/src/utils/ModuleBase.js b/src/utils/ModuleBase.js
index 46a06f69..fd93935f 100644
--- a/src/utils/ModuleBase.js
+++ b/src/utils/ModuleBase.js
@@ -10,7 +10,7 @@ import type { FirebaseModuleConfig, FirebaseNamespace } from '../types';
 export default class ModuleBase {
   _app: App;
 
-  _serviceUrl: ?string;
+  _customUrlOrRegion: ?string;
 
   namespace: FirebaseNamespace;
 
@@ -18,21 +18,29 @@ export default class ModuleBase {
    *
    * @param app
    * @param config
+   * @param customUrlOrRegion
    */
-  constructor(app: App, config: FirebaseModuleConfig, serviceUrl: ?string) {
+  constructor(
+    app: App,
+    config: FirebaseModuleConfig,
+    customUrlOrRegion: ?string
+  ) {
     if (!config.moduleName) {
       throw new Error('Missing module name');
     }
+
     if (!config.namespace) {
       throw new Error('Missing namespace');
     }
+
     const { moduleName } = config;
     this._app = app;
-    this._serviceUrl = serviceUrl;
+    this._customUrlOrRegion = customUrlOrRegion;
     this.namespace = config.namespace;
 
     // check if native module exists as all native
-    initialiseNativeModule(this, config, serviceUrl);
+    initialiseNativeModule(this, config, customUrlOrRegion);
+
     initialiseLogger(
       this,
       `${app.name}:${moduleName.replace('RNFirebase', '')}`
diff --git a/src/utils/apps.js b/src/utils/apps.js
index d219f7eb..3326d1fa 100644
--- a/src/utils/apps.js
+++ b/src/utils/apps.js
@@ -49,38 +49,50 @@ export default {
     namespace: FirebaseNamespace,
     InstanceClass: Class<M>
   ): () => FirebaseModule {
-    return (serviceUrl: ?string = null): M => {
-      if (serviceUrl && namespace !== 'database') {
+    return (customUrlOrRegion: ?string = null): M => {
+      if (
+        customUrlOrRegion &&
+        (namespace !== 'database' || namespace !== 'functions')
+      ) {
         throw new Error(
-          INTERNALS.STRINGS.ERROR_INIT_SERVICE_URL_UNSUPPORTED(namespace)
+          INTERNALS.STRINGS.ERROR_INIT_SERVICE_URL_OR_REGION_UNSUPPORTED(
+            namespace
+          )
         );
       }
 
-      const appOrShardName = serviceUrl || app.name;
-      if (!APP_MODULES[appOrShardName]) {
-        APP_MODULES[appOrShardName] = {};
+      const appInstanceIdentifier = `${app.name}${customUrlOrRegion || ''}`;
+
+      if (!APP_MODULES[appInstanceIdentifier]) {
+        APP_MODULES[appInstanceIdentifier] = {};
       }
 
-      if (
-        isAndroid &&
-        namespace !== 'utils' &&
-        !INTERNALS.FLAGS.checkedPlayServices
-      ) {
-        INTERNALS.FLAGS.checkedPlayServices = true;
-        app.utils().checkPlayServicesAvailability();
-      }
-
-      if (!APP_MODULES[appOrShardName][namespace]) {
-        APP_MODULES[appOrShardName][namespace] = new InstanceClass(
-          serviceUrl || app,
+      if (!APP_MODULES[appInstanceIdentifier][namespace]) {
+        APP_MODULES[appInstanceIdentifier][namespace] = new InstanceClass(
+          customUrlOrRegion || app,
           app.options
         );
+
+        // only check once on new app namespace instance
+        if (
+          isAndroid &&
+          namespace !== 'utils' &&
+          !INTERNALS.FLAGS.checkedPlayServices
+        ) {
+          INTERNALS.FLAGS.checkedPlayServices = true;
+          app.utils().checkPlayServicesAvailability();
+        }
       }
 
-      return APP_MODULES[appOrShardName][namespace];
+      return APP_MODULES[appInstanceIdentifier][namespace];
     };
   },
 
+  /**
+   *
+   * @param name
+   * @returns {*}
+   */
   deleteApp(name: string): Promise<boolean> {
     const app = APPS[name];
     if (!app) return Promise.resolve(true);
@@ -173,24 +185,31 @@ export default {
     statics: S,
     moduleName: FirebaseModuleName
   ): FirebaseModuleAndStatics<M, S> {
-    const getModule = (appOrUrl?: App | string): FirebaseModule => {
-      let _app = appOrUrl;
-      let _serviceUrl: ?string = null;
-      if (typeof appOrUrl === 'string' && namespace === 'database') {
+    const getModule = (appOrUrlOrRegion?: App | string): FirebaseModule => {
+      let _app = appOrUrlOrRegion;
+      let _customUrlOrRegion: ?string = null;
+
+      if (typeof appOrUrlOrRegion === 'string' && namespace === 'database') {
         _app = null;
-        _serviceUrl = appOrUrl;
+        _customUrlOrRegion = appOrUrlOrRegion;
+      }
+
+      if (typeof appOrUrlOrRegion === 'string' && namespace === 'functions') {
+        _app = null;
+        _customUrlOrRegion = appOrUrlOrRegion;
       }
 
       // throw an error if it's not a valid app instance
-      if (_app && !(_app instanceof App))
+      if (_app && !(_app instanceof App)) {
         throw new Error(INTERNALS.STRINGS.ERROR_NOT_APP(namespace));
-      else if (!_app)
+      } else if (!_app) {
         // default to the 'DEFAULT' app if no arg provided - will throw an error
         // if default app not initialized
         _app = this.app(DEFAULT_APP_NAME);
+      }
       // $FlowExpectedError: Flow doesn't support indexable signatures on classes: https://github.com/facebook/flow/issues/1323
       const module = _app[namespace];
-      return module(_serviceUrl);
+      return module(_customUrlOrRegion);
     };
 
     return Object.assign(getModule, statics, {
diff --git a/src/utils/events.js b/src/utils/events.js
index 1d53798e..7b99ed77 100644
--- a/src/utils/events.js
+++ b/src/utils/events.js
@@ -23,9 +23,11 @@ const getNativeEmitter = (
 ): NativeEventEmitter => {
   const name = `${module.app.name}-${moduleName}`;
   const nativeModule = NativeModules[moduleName];
+
   if (!NATIVE_EMITTERS[name]) {
     NATIVE_EMITTERS[name] = new NativeEventEmitter(nativeModule);
   }
+
   return NATIVE_EMITTERS[name];
 };
 
@@ -35,6 +37,7 @@ const getNativeEmitter = (
  *    so we use a single event send it to js and js then internally can prefix it
  *    and distribute dynamically.
  *
+ * @param moduleName
  * @param module
  * @param eventName
  * @private
@@ -65,6 +68,7 @@ export const initialiseNativeModuleEventEmitter = (
   config: FirebaseModuleConfig
 ): void => {
   const { events, moduleName } = config;
+
   if (events && events.length) {
     for (let i = 0, len = events.length; i < len; i++) {
       subscribeToNativeModuleEvents(moduleName, module, events[i]);
diff --git a/src/utils/internals.js b/src/utils/internals.js
index 419bd5f1..f63395de 100644
--- a/src/utils/internals.js
+++ b/src/utils/internals.js
@@ -100,8 +100,8 @@ export default {
     /**
      * @return {string}
      */
-    ERROR_INIT_SERVICE_URL_UNSUPPORTED(namespace: string) {
-      return `${namespace} does not support URL as a param, please pass in an app.`;
+    ERROR_INIT_SERVICE_URL_OR_REGION_UNSUPPORTED(namespace: string) {
+      return `${namespace} does not support a URL or region as a param, please pass in an app.`;
     },
 
     /**
diff --git a/src/utils/native.js b/src/utils/native.js
index 1b8ddd66..95cdd982 100644
--- a/src/utils/native.js
+++ b/src/utils/native.js
@@ -32,7 +32,7 @@ const nativeWithArgs = (
 };
 
 const nativeModuleKey = (module: ModuleBase): string =>
-  `${module._serviceUrl || module.app.name}:${module.namespace}`;
+  `${module._customUrlOrRegion || module.app.name}:${module.namespace}`;
 
 export const getNativeModule = (module: ModuleBase): Object =>
   NATIVE_MODULES[nativeModuleKey(module)];
@@ -40,9 +40,9 @@ export const getNativeModule = (module: ModuleBase): Object =>
 export const initialiseNativeModule = (
   module: ModuleBase,
   config: FirebaseModuleConfig,
-  serviceUrl: ?string
+  customUrlOrRegion: ?string
 ): Object => {
-  const { moduleName, multiApp, hasShards, namespace } = config;
+  const { moduleName, hasMultiAppSupport, hasCustomUrlSupport, hasRegionsSupport, namespace } = config;
   const nativeModule = NativeModules[moduleName];
   const key = nativeModuleKey(module);
 
@@ -55,11 +55,13 @@ export const initialiseNativeModule = (
   // used by the modules that extend ModuleBase
   // to access their native module counterpart
   const argToPrepend = [];
-  if (multiApp) {
+
+  if (hasMultiAppSupport) {
     argToPrepend.push(module.app.name);
   }
-  if (hasShards) {
-    argToPrepend.push(serviceUrl);
+
+  if (hasCustomUrlSupport || hasRegionsSupport) {
+    argToPrepend.push(customUrlOrRegion);
   }
 
   if (argToPrepend.length) {