Watch demos on how to build & run AI-powered apps with Firebase at Demo Day '24. Watch now.

Get started with Firebase Remote Config

You can use Firebase Remote Config to define parameters in your app and update their values in the cloud, allowing you to modify the appearance and behavior of your app without distributing an app update. This guide walks you through the steps to get started and provides some sample code.

Step 1: Add Firebase and the Remote Config SDK to your app

Install and initialize the Firebase SDKs for Flutter if you haven't already done so.
For Remote Config, Google Analytics is required for the conditional targeting of app instances to user properties and audiences. Make sure that you enable Google Analytics in your project.
From the root directory of your Flutter project, run the following command to install the Remote Config plugin:
```
flutter pub add firebase_remote_config
```
Also, as part of setting up Remote Config, you need to add the Firebase SDK for Google Analytics to your app:
```
flutter pub add firebase_analytics
```
Rebuild your project:
```
flutter run
```
If you're using Remote Config on macOS, enable Keychain Sharing in Xcode.

Step 2: Get the Remote Config singleton object

Get a Remote Config object instance and set the minimum fetch interval to allow for frequent refreshes:

final remoteConfig = FirebaseRemoteConfig.instance;
await remoteConfig.setConfigSettings(RemoteConfigSettings(
    fetchTimeout: const Duration(minutes: 1),
    minimumFetchInterval: const Duration(hours: 1),
));

The singleton object is used to store in-app default parameter values, fetch updated parameter values from the backend, and control when fetched values are made available to your app.

During development, it's recommended to set a relatively low minimum fetch interval. See Throttling for more information.

Step 3: Set in-app default parameter values

You can set in-app default parameter values in the Remote Config object, so that your app behaves as intended before it connects to the Remote Config backend, and so that default values are available if none are set in the backend.

await remoteConfig.setDefaults(const {
    "example_param_1": 42,
    "example_param_2": 3.14159,
    "example_param_3": true,
    "example_param_4": "Hello, world!",
});

Step 4: Get parameter values to use in your app

Now you can get parameter values from the Remote Config object. If you set values in the backend, fetch them, and then activate them, those values are available to your app. Otherwise, you get the in-app parameter values configured using setDefaults().

To get these values, call the method listed below that maps to the data type expected by your app, providing the parameter key as an argument:

getBool()
getDouble()
getInt()
getString()

Step 5: Set parameter values in the Remote Config backend

Using the Firebase console or the Remote Config backend APIs, you can create new server-side default values that override the in-app values according to your desired conditional logic or user targeting. This section describes the Firebase console steps to create these values.

In the Firebase console, open your project.
Select Remote Config from the menu to view the Remote Config dashboard.
Define parameters with the same names as the parameters that you defined in your app. For each parameter, you can set a default value (which will eventually override the corresponding in-app default value), and you can also set conditional values. To learn more, see Remote Config Parameters and Conditions.

Step 6: Fetch and activate values

To fetch parameter values from the Remote Config backend, call the fetch() method. Any values that you set in the backend are fetched and stored in the Remote Config object.
To make fetched parameter values available to your app, call the activate() method.

For cases where you want to fetch and activate values in one call, you can use a fetchAndActivate() request to fetch values from the Remote Config backend and make them available to the app:
```
await remoteConfig.fetchAndActivate();
```

Because these updated parameter values affect the behavior and appearance of your app, you should activate the fetched values at a time that ensures a smooth experience for your user, such as the next time that the user opens your app. See Remote Config loading strategies for more information and examples.

Step 7: Listen for updates in real time

After you fetch parameter values, you can use real-time Remote Config to listen for updates from the Remote Config backend. Real-time Remote Config signals to connected devices when updates are available and automatically fetches the changes after you publish a new Remote Config version.

Note that real-time Remote Config is not available for Web.

In your app, use onConfigUpdated to start listening for updates and automatically fetch any new parameter values.

 remoteConfig.onConfigUpdated.listen((event) async {
   await remoteConfig.activate();

   // Use the new config values here.
 });

The next time you publish a new version of your Remote Config, devices that are running your app and listening for changes will activate the new config.

Throttling

If an app fetches too many times in a short time period, fetch calls will be throttled and the value of FirebaseRemoteConfig's lastFetchStatus property will be RemoteConfigFetchStatus.throttle.

The default minimum fetch interval for Remote Config is 12 hours, which means that configs won't be fetched from the backend more than once in a 12 hour window, regardless of how many fetch calls are actually made.

During app development, if you're not using real-time Remote Config (which we recommend), you might want to fetch and activate configs very frequently (many times per hour) to let you rapidly iterate as you develop and test your app. To accommodate rapid iteration on a project with up to 10 developers, you can temporarily set a low minimum fetch interval with setConfigSettings().

final remoteConfig = FirebaseRemoteConfig.instance;
await remoteConfig.setConfigSettings(RemoteConfigSettings(
    fetchTimeout: const Duration(minutes: 1),
    minimumFetchInterval: const Duration(minutes: 5),
));

Next steps

If you haven't already, explore the Remote Config use cases, and take a look at some of the key concepts and advanced strategies documentation, including: