IMPORTANT: In July 2025, we stopped releasing new versions of KTX modules, and we removed the KTX libraries from the Firebase Android BoM (v34.0.0). If you use KTX APIs from the previously released KTX modules, we recommend that you migrate your app to use KTX APIs from the main modules instead. For details, see the FAQ about this initiative.

FirebaseApp

public class FirebaseApp

The entry point of Firebase SDKs. It holds common configuration and state for Firebase APIs. Most applications don't need to directly interact with FirebaseApp.

For a vast majority of apps, FirebaseInitProvider will handle the initialization of Firebase for the default project that it's configured to work with, via the data contained in the app's google-services.json file. This ContentProvider is merged into the app's manifest by default when building with Gradle, and it runs automatically at app launch. No additional lines of code are needed in this case.

In the event that an app requires access to another Firebase project in addition to the default project, initializeApp must be used to create that relationship programmatically. The name parameter must be unique. To connect to the resources exposed by that project, use the FirebaseApp object returned by getInstance, passing it the same name used with initializeApp. This object must be passed to the static accessor of the feature that provides the resource. For example, getInstance is used to access the storage bucket provided by the additional project, whereas getInstance is used to access the default project.

Any FirebaseApp initialization must occur only in the main process of the app. Use of Firebase in processes other than the main process is not supported and will likely cause problems related to resource contention.

Summary

Constants
`static final @NonNull String`	`DEFAULT_APP_NAME = "[DEFAULT]"`

Public fields
`final Context`	`applicationContext`
`final String`	`name`
`final FirebaseOptions`	`options`

Public methods
`boolean`	`equals(Object o)`
`@NonNull Context`	`getApplicationContext()` Returns the application `Context`.
`static @NonNull List<FirebaseApp>`	`getApps(@NonNull Context context)` Returns a mutable list of all FirebaseApps.
`static @NonNull FirebaseApp`	`getInstance()` Returns the default (first initialized) instance of the `FirebaseApp`.
`static @NonNull FirebaseApp`	`getInstance(@NonNull String name)` Returns the instance identified by the unique name, or throws if it does not exist.
`@NonNull String`	`getName()` Returns the unique name of this app.
`@NonNull FirebaseOptions`	`getOptions()` Returns the specified `FirebaseOptions`.
`int`	`hashCode()`
`static @Nullable FirebaseApp`	`initializeApp(@NonNull Context context)` Initializes the default FirebaseApp instance using string resource values - populated from google-services.json.
`static @NonNull FirebaseApp`	`initializeApp(@NonNull Context context, @NonNull FirebaseOptions options)` Initializes the default `FirebaseApp` instance.
`static @NonNull FirebaseApp`	`initializeApp( @NonNull Context context, @NonNull FirebaseOptions options, @NonNull String name )` A factory method to initialize a `FirebaseApp`.
`void`	`setAutomaticResourceManagementEnabled(boolean enabled)` If set to true it indicates that Firebase should close database connections automatically when the app is in the background.
`String`	`toString()`

Constants

DEFAULT_APP_NAME

public static final @NonNull String DEFAULT_APP_NAME = "[DEFAULT]"

Public fields

applicationContext

public final Context applicationContext

name

public final String name

options

public final FirebaseOptions options

Public methods

equals

public boolean equals(Object o)

getApplicationContext

public @NonNull Context getApplicationContext()

Returns the application Context.

getApps

public static @NonNull List<FirebaseApp> getApps(@NonNull Context context)

Returns a mutable list of all FirebaseApps.

getInstance

public static @NonNull FirebaseApp getInstance()

Returns the default (first initialized) instance of the FirebaseApp.

Throws
`java.lang.IllegalStateException java.lang.IllegalStateException`	if the default app was not initialized.

getInstance

public static @NonNull FirebaseApp getInstance(@NonNull String name)

Returns the instance identified by the unique name, or throws if it does not exist.

Parameters
`@NonNull String name`	represents the name of the `FirebaseApp` instance.

Throws
`java.lang.IllegalStateException java.lang.IllegalStateException`	if the `FirebaseApp` was not initialized, either via `initializeApp`.

getName

public @NonNull String getName()

Returns the unique name of this app.

getOptions

public @NonNull FirebaseOptions getOptions()

Returns the specified FirebaseOptions.

hashCode

public int hashCode()

initializeApp

public static @Nullable FirebaseApp initializeApp(@NonNull Context context)

Initializes the default FirebaseApp instance using string resource values - populated from google-services.json. It also initializes Firebase Analytics for the current process.

This method is called at app startup time by FirebaseInitProvider. Call this method before any Firebase APIs in components outside the main process.

The FirebaseOptions values used by the default app instance are read from string resources.

Returns
`@Nullable FirebaseApp`	the default FirebaseApp, if either it has been initialized previously, or Firebase API keys are present in string resources. Returns null otherwise.

initializeApp

public static @NonNull FirebaseApp initializeApp(@NonNull Context context, @NonNull FirebaseOptions options)

Initializes the default FirebaseApp instance. Same as initializeApp, but it uses DEFAULT_APP_NAME as name.

It's only required to call this to initialize Firebase if it's not possible to do so automatically in FirebaseInitProvider. Automatic initialization that way is the expected situation.

initializeApp

public static @NonNull FirebaseApp initializeApp(
    @NonNull Context context,
    @NonNull FirebaseOptions options,
    @NonNull String name
)

A factory method to initialize a FirebaseApp.

Parameters
`@NonNull Context context`	represents the `Context`
`@NonNull FirebaseOptions options`	represents the global `FirebaseOptions`
`@NonNull String name`	unique name for the app. It is an error to initialize an app with an already existing name. Starting and ending whitespace characters in the name are ignored (trimmed).

Returns
`@NonNull FirebaseApp`	an instance of `FirebaseApp`

Throws
`java.lang.IllegalStateException java.lang.IllegalStateException`	if an app with the same name has already been initialized.

setAutomaticResourceManagementEnabled

public void setAutomaticResourceManagementEnabled(boolean enabled)

If set to true it indicates that Firebase should close database connections automatically when the app is in the background. Disabled by default.

toString

public String toString()