Remote Config

Type-safe Remote Config built with Clean Architecture. Define typed keys, provide safe defaults, deserialize custom JSON, use values in ViewModels or Compose. Firebase-backed by default; swap RemoteConfigRepository for a local/test impl.

Where things live

Piece	Module	Path
RemoteConfigKey<T> (base)	remote_config domain	features/remote_config/domain/.../RemoteConfigKey.kt
GetConfigLogic	remote_config domain	features/remote_config/domain/.../logics/GetConfigLogic.kt
RemoteConfigRepository (interface)	remote_config domain	features/remote_config/domain/.../RemoteConfigRepository.kt
FirebaseRemoteConfigRepository	remote_config data	features/remote_config/data/.../FirebaseRemoteConfigRepository.kt
rememberRemoteConfig	remote_config presentation	features/remote_config/presentation/.../RememberConfig.kt

1. Define keys (one sealed hierarchy)

Extend RemoteConfigKey<T>. Keep one sealed ConfigKeys hierarchy per app:

@Serializable
data class PromoConfig(
    val isEnabled: Boolean = false,
    val discountPercentage: Int = 0,
)

sealed class ConfigKeys<T>(
    key: String,
    defaultValue: T,
    serializer: KSerializer<T>? = null,
) : RemoteConfigKey<T>(key = key, defaultValue = defaultValue, serializer = serializer) {

    data class ShowAds(
        override val defaultValue: Boolean = false,
    ) : RemoteConfigKey<Boolean>(key = "show_ads", defaultValue = defaultValue)

    data class WelcomeText(
        override val defaultValue: String = "Welcome to KMP Starter",
    ) : RemoteConfigKey<String>(key = "welcome_text", defaultValue = defaultValue)

    data class Promo(
        override val defaultValue: PromoConfig = PromoConfig(),
    ) : RemoteConfigKey<PromoConfig>(
        key = "promo_config",
        defaultValue = defaultValue,
        serializer = PromoConfig.serializer(),
    )

    data class MinimumVersion(
        override val defaultValue: Int = 36,
    ) : RemoteConfigKey<Int>(key = "minimum_version", defaultValue = defaultValue)
}

Rules:

• Override defaultValue so defaults stay at the call site.
• Keys must exactly match Firebase console keys.
• Always provide safe defaults.
• Pass serializer for @Serializable custom objects (primitives don't need one).

2. Use in a ViewModel

Inject GetConfigLogic and invoke it with a key instance (it's an operator fun invoke):

class HomeViewModel(
    private val getConfig: GetConfigLogic,
) : MviViewModel<HomeState, HomeActions, HomeEvents>() {

    init {
        viewModelScope.launch {
            // getConfig(ConfigKeys.ShowAds()) returns Boolean
            _state.update { it.copy(showAds = getConfig(ConfigKeys.ShowAds())) }
        }
    }
}

GetConfigLogic waits for initialization; on failure it returns the key's default. Primitives (Boolean/Int/Long/Double/Float/String) are coerced from the raw string; custom objects are decoded via their serializer.

3. Use in Compose

@Composable
fun HomeScreen() {
    val showAds by rememberRemoteConfig(key = ConfigKeys.ShowAds())
    val promo by rememberRemoteConfig(key = ConfigKeys.Promo())

    if (showAds) AdBanner()
    if (promo.isEnabled) Text("Discount: ${promo.discountPercentage}%")
}

Starts with the default, updates after fetch. rememberRemoteConfig uses koinInject() internally.

4. Initialization

Already wired in the app entry point by default; requires Firebase. RemoteConfig.init(minimumFetchInterval, fetchTimeout) controls fetch cadence.

5. Swap the provider (local/test)

Implement RemoteConfigRepository in features/remote_config/data/, bind in remoteConfigDataModule:

class LocalRemoteConfigRepository : RemoteConfigRepository {
    private val storage = mapOf(
        "show_ads" to "true",
        "promo_config" to """{"isEnabled":true,"discountPercentage":30}""",
    )
    override fun get(key: String): RemoteConfigValue = storage[key] ?: ""
}

Useful for unit tests, desktop builds, CI, offline dev.

Rules

• Do not introduce a parallel config system.
• One sealed key hierarchy; every screen reads config through the same typed models.
• Register remoteConfigDataModule + remoteConfigDomainModule in InitKoin (see koin skill).

Reference

• Docs: https://starter.atherio.dev/features/ → Remote Config
• Source: features/remote_config/*