diff --git a/lib/index.d.ts b/lib/index.d.ts
index 4a143322..e4e222b6 100644
--- a/lib/index.d.ts
+++ b/lib/index.d.ts
@@ -1511,7 +1511,7 @@ declare module 'react-native-firebase' {
          * The default duration is 43200 seconds (12 hours).
          * To force a cache refresh call the method with a duration of 0.
          */
-        fetch(duration?: number): Promise<void>;
+        fetch(duration?: number): Promise<string>;
 
         /**
          * Fetches the remote config data from Firebase, defined in the dashboard.
@@ -1536,6 +1536,11 @@ declare module 'react-native-firebase' {
          */
         getKeysByPrefix(prefix?: string): Promise<Array<String>>;
 
+        /**
+         * Sets config defaults for parameter keys and values in the default namespace config.
+         */
+        setDefault(defaults: Object): void;
+
         /**
          * Sets the default values from a resource:
          * - Android: Id for the XML resource, which should be in your application's res/xml folder.
diff --git a/lib/modules/config/index.js b/lib/modules/config/index.js
index 05511262..aa5e8a42 100644
--- a/lib/modules/config/index.js
+++ b/lib/modules/config/index.js
@@ -22,6 +22,11 @@ type NativeValue = {
 export const MODULE_NAME = 'RNFirebaseRemoteConfig';
 export const NAMESPACE = 'config';
 
+type ConfigSnapshot = {
+  source: string,
+  val(): any,
+};
+
 /**
  * @class Config
  */
@@ -44,7 +49,7 @@ export default class RemoteConfig extends ModuleBase {
    * @returns {*}
    * @private
    */
-  _nativeValueToJS(nativeValue: NativeValue) {
+  _nativeValueToJS(nativeValue: NativeValue): ConfigSnapshot {
     return {
       source: nativeValue.source,
       val() {
@@ -89,7 +94,7 @@ export default class RemoteConfig extends ModuleBase {
    * Call activateFetched to make fetched data available in app
    * @returns {*|Promise.<String>}:
    */
-  fetch(expiration?: number) {
+  fetch(expiration?: number): Promise<string> {
     if (expiration !== undefined) {
       getLogger(this).debug(
         `Fetching remote config data with expiration ${expiration.toString()}`
@@ -106,7 +111,7 @@ export default class RemoteConfig extends ModuleBase {
    * resolves if there was a Fetched Config, and it was activated,
    * rejects if no Fetched Config was found, or the Fetched Config was already activated.
    */
-  activateFetched() {
+  activateFetched(): Promise<boolean> {
     getLogger(this).debug('Activating remote config');
     return getNativeModule(this).activateFetched();
   }
@@ -124,7 +129,7 @@ export default class RemoteConfig extends ModuleBase {
    *    "source" : OneOf<String>(remoteConfigSourceRemote|remoteConfigSourceDefault|remoteConfigSourceStatic)
    *  }
    */
-  getValue(key: string) {
+  getValue(key: string): Promise<ConfigSnapshot> {
     return getNativeModule(this)
       .getValue(key || '')
       .then(this._nativeValueToJS);
@@ -144,7 +149,7 @@ export default class RemoteConfig extends ModuleBase {
    *    "source" : OneOf<String>(remoteConfigSourceRemote|remoteConfigSourceDefault|remoteConfigSourceStatic)
    *  }
    */
-  getValues(keys: Array<string>) {
+  getValues(keys: Array<string>): Promise<{ [string]: ConfigSnapshot }> {
     return getNativeModule(this)
       .getValues(keys || [])
       .then(nativeValues => {
@@ -161,7 +166,7 @@ export default class RemoteConfig extends ModuleBase {
    * @param prefix: The key prefix to look for. If prefix is nil or empty, returns all the keys.
    * @returns {*|Promise.<Array<String>>}
    */
-  getKeysByPrefix(prefix?: string) {
+  getKeysByPrefix(prefix?: string): Promise<string[]> {
     return getNativeModule(this).getKeysByPrefix(prefix);
   }
 
@@ -169,7 +174,7 @@ export default class RemoteConfig extends ModuleBase {
    * Sets config defaults for parameter keys and values in the default namespace config.
    * @param defaults: A dictionary mapping a String key to a Object values.
    */
-  setDefaults(defaults: Object) {
+  setDefaults(defaults: Object): void {
     getNativeModule(this).setDefaults(defaults);
   }
 
@@ -177,7 +182,7 @@ export default class RemoteConfig extends ModuleBase {
    * Sets default configs from plist for default namespace;
    * @param resource: The plist file name or resource ID
    */
-  setDefaultsFromResource(resource: string | number) {
+  setDefaultsFromResource(resource: string | number): void {
     getNativeModule(this).setDefaultsFromResource(resource);
   }
 }