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, all of which is available to clone or download from the firebase/quickstart-android GitHub repository.

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

  1. If you haven't already, add Firebase to your Android project.

  2. 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.

  3. In your module (app-level) Gradle file (usually <project>/<app-module>/build.gradle.kts or <project>/<app-module>/build.gradle), add the dependency for the Remote Config library for Android. We recommend using the Firebase Android BoM to control library versioning.

    Also, as part of setting up Analytics, you need to add the Firebase SDK for Google Analytics to your app.

    dependencies {
    // Import the BoM for the Firebase platform
    implementation(platform("com.google.firebase:firebase-bom:33.6.0"))

    // Add the dependencies for the Remote Config and Analytics libraries
    // When using the BoM, you don't specify versions in Firebase library dependencies
    implementation("com.google.firebase:firebase-config")
    implementation("com.google.firebase:firebase-analytics")
}

    By using the Firebase Android BoM, your app will always use compatible versions of Firebase Android libraries.

    (Alternative)  Add Firebase library dependencies without using the BoM

    If you choose not to use the Firebase BoM, you must specify each Firebase library version in its dependency line.

    Note that if you use multiple Firebase libraries in your app, we strongly recommend using the BoM to manage library versions, which ensures that all versions are compatible. 

    dependencies {
    // Add the dependencies for the Remote Config and Analytics libraries
    // When NOT using the BoM, you must specify versions in Firebase library dependencies
    implementation("com.google.firebase:firebase-config:22.0.1")
    implementation("com.google.firebase:firebase-analytics:22.1.2")
}
    Looking for a Kotlin-specific library module? Starting in October 2023 (Firebase BoM 32.5.0), both Kotlin and Java developers can depend on the main library module (for details, see the FAQ about this initiative).

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:

Kotlin+KTX 

val remoteConfig: FirebaseRemoteConfig = Firebase.remoteConfig
val configSettings = remoteConfigSettings {
    minimumFetchIntervalInSeconds = 3600
}
remoteConfig.setConfigSettingsAsync(configSettings)
MainActivity.kt

Java 

FirebaseRemoteConfig mFirebaseRemoteConfig = FirebaseRemoteConfig.getInstance();
FirebaseRemoteConfigSettings configSettings = new FirebaseRemoteConfigSettings.Builder()
        .setMinimumFetchIntervalInSeconds(3600)
        .build();
mFirebaseRemoteConfig.setConfigSettingsAsync(configSettings);
MainActivity.java

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.

  1. Define a set of parameter names and default parameter values using a Map object or an XML resource file stored in your app's res/xml folder. The Remote Config quickstart sample app uses an XML file to define default parameter names and values.

    If you have already configured Remote Config backend parameter values, you can download a generated XML file that includes all default values and save it to your app's res/xml directory:

    REST

    curl --compressed -D headers -H "Authorization: Bearer token" -X GET https://firebaseremoteconfig.googleapis.com/v1/projects/my-project-id/remoteConfig:downloadDefaults?format=XML -o remote_config_defaults.xml

    Firebase console

    1. In the Parameters tab, open the Menu, and select Download default values.

    2. When prompted, enable .xml for Android, then click Download file.

  2. Add these values to the Remote Config object using setDefaultsAsync(int), as shown:

    Kotlin+KTX 

    remoteConfig.setDefaultsAsync(R.xml.remote_config_defaults)

    Java 

    mFirebaseRemoteConfig.setDefaultsAsync(R.xml.remote_config_defaults);

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 setDefaultsAsync(int). 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:

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.

  1. In the Firebase console, open your project.
  2. Select Remote Config from the menu to view the Remote Config dashboard.
  3. 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

  1. 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.

  2. 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:

    Kotlin+KTX 

    remoteConfig.fetchAndActivate()
    .addOnCompleteListener(this) { task ->
        if (task.isSuccessful) {
            val updated = task.result
            Log.d(TAG, "Config params updated: $updated")
            Toast.makeText(
                this,
                "Fetch and activate succeeded",
                Toast.LENGTH_SHORT,
            ).show()
        } else {
            Toast.makeText(
                this,
                "Fetch failed",
                Toast.LENGTH_SHORT,
            ).show()
        }
        displayWelcomeMessage()
    }

    Java 

    mFirebaseRemoteConfig.fetchAndActivate()
        .addOnCompleteListener(this, new OnCompleteListener<Boolean>() {
            @Override
            public void onComplete(@NonNull Task<Boolean> task) {
                if (task.isSuccessful()) {
                    boolean updated = task.getResult();
                    Log.d(TAG, "Config params updated: " + updated);
                    Toast.makeText(MainActivity.this, "Fetch and activate succeeded",
                            Toast.LENGTH_SHORT).show();

                } else {
                    Toast.makeText(MainActivity.this, "Fetch failed",
                            Toast.LENGTH_SHORT).show();
                }
                displayWelcomeMessage();
            }
        });

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.

Real-time updates are supported by the Firebase SDK for Android v21.3.0+ (Firebase BoM v31.2.4+).

  1. In your app, use addOnConfigUpdateListener() to start listening for updates and automatically fetch any new parameter values. Implement the onUpdate() callback to activate the updated config.

    Kotlin+KTX 

    remoteConfig.addOnConfigUpdateListener(object : ConfigUpdateListener {
    override fun onUpdate(configUpdate : ConfigUpdate) {
       Log.d(TAG, "Updated keys: " + configUpdate.updatedKeys);

       if (configUpdate.updatedKeys.contains("welcome_message")) {
           remoteConfig.activate().addOnCompleteListener {
               displayWelcomeMessage()
           }
       }
    }

    override fun onError(error : FirebaseRemoteConfigException) {
        Log.w(TAG, "Config update error with code: " + error.code, error)
    }
})

    Java 

    mFirebaseRemoteConfig.addOnConfigUpdateListener(new ConfigUpdateListener() {
    @Override
    public void onUpdate(ConfigUpdate configUpdate) {
        Log.d(TAG, "Updated keys: " + configUpdate.getUpdatedKeys());
        mFirebaseRemoteConfig.activate().addOnCompleteListener(new OnCompleteListener<Boolean>() {
            @Override
            public void onComplete(@NonNull Task<Boolean> task) {
                displayWelcomeMessage();
            }
        });
    }
    @Override
    public void onError(FirebaseRemoteConfigException error) {
        Log.w(TAG, "Config update error with code: " + error.getCode(), error);
    }
});

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

Throttling

If an app fetches too many times in a short time period, fetch calls are throttled and the SDK returns FirebaseRemoteConfigFetchThrottledException. Before SDK version 17.0.0, the limit was 5 fetch requests in a 60 minute window (newer versions have more permissive limits).

During app development, 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. Real-time Remote Config updates automatically bypass the cache when the config is updated on the server. To accommodate rapid iteration on a project with up to 10 developers, you can temporarily set a FirebaseRemoteConfigSettings object with a low minimum fetch interval (setMinimumFetchIntervalInSeconds) in your app.

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. Specifically, the minimum fetch interval is determined in this following order:

  1. The parameter in fetch(long)
  2. The parameter in FirebaseRemoteConfigSettings.setMinimumFetchIntervalInSeconds(long)
  3. The default value of 12 hours

To set the minimum fetch interval to a custom value, use FirebaseRemoteConfigSettings.Builder.setMinimumFetchIntervalInSeconds(long).

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: