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    Send a test message to a backgrounded app

    To get started with FCM , build out the simplest use case: sending a test notification message from the Notifications composer to a development device when the app is in the background on the device. This page lists all the steps to achieve this, from setup to verification — it may cover steps you already completed if you have set up an Android client app for FCM .

    Set up the SDK

    This section covers tasks you may have completed if you have already enabled other Firebase features for your app.

    Before you begin

    • Install or update Android Studio to its latest version.

    • Make sure that your project meets these requirements (note that some products might have stricter requirements):

      • Targets API level 21 (Lollipop) or higher
      • Uses Android 5.0 or higher
      • Uses Jetpack (AndroidX) , which includes meeting these version requirements:
        • com.android.tools.build:gradle v7.3.0 or later
        • compileSdkVersion 28 or later

    • Set up a physical device or use an emulator to run your app.Note that Firebase SDKs with a dependency on Google Play services require the device or emulator to have Google Play services installed.

    • Sign into Firebase using your Google account.

    If you don't already have an Android project and just want to try out a Firebase product, you can download one of our quickstart samples .

    Create a Firebase project

    Before you can add Firebase to your Android app, you need to create a Firebase project to connect to your Android app. Visit Understand Firebase Projects to learn more about Firebase projects.

    Register your app with Firebase

    To use Firebase in your Android app, you need to register your app with your Firebase project. Registering your app is often called "adding" your app to your project.

    1. Go to the Firebase console .

    2. In the center of the project overview page, click the Androidicon ( ) or Add appto launch the setup workflow.

    3. Enter your app's package name in the Android package namefield.

      What's a package name, and where do you find it?

      • A package name uniquely identifies your app on the device and in the Google Play Store.

      • A package name is often referred to as an application ID .

      • Find your app's package name in your module (app-level) Gradle file, usually app/build.gradle (example package name: com.yourcompany.yourproject ).

      • Be aware that the package name value is case-sensitive, and it cannot be changed for this Firebase Android app after it's registered with your Firebase project.

  • (Optional) Enter other app information: App nicknameand Debug signing certificate SHA-1.

    How are the App nickname and the Debug signing certificate SHA-1 used within Firebase?

  • Click Register app.

    • Add a Firebase configuration file

    1. Download and then add your app's Firebase config file ( google-services.json ) to your codebase:

      1. Click Download google-services.jsonto obtain your app's Firebase config file.

      2. Move your config file into the module (app-level)root directory of your app.

      What do you need to know about this config file?

      • The Firebase config file contains unique, but non-secret identifiers for your project and app. To learn more about this config file, visit Understand Firebase Projects .

      • You can download your Firebase config file again at any time.

      • Make sure the config file name is not appended with additional characters, like (2) .

    2. To make the values in your google-services.json config file accessible to Firebase SDKs, you need the Google services Gradle plugin ( google-services ).

      1. In your root-level (project-level)Gradle file ( <project>/build.gradle.kts or <project>/build.gradle ), add the Google services plugin as a dependency:

        Kotlin 

         plugins 
  
 { 
  
 id 
 ( 
 "com.android.application" 
 ) 
  
 version 
  
 "7.3.0" 
  
 apply 
  
 false 
  
 // ... 
  
  // Add the dependency for the Google services Gradle plugin 
  
 id 
 ( 
 "com.google.gms.google-services" 
 ) 
  
 version 
  
 "4.4.3" 
  
 apply 
  
 false 
 }

        Groovy 

         plugins 
  
 { 
  
 id 
  
 'com.android.application' 
  
 version 
  
 '7.3.0' 
  
 apply 
  
 false 
  
 // ... 
  
  // Add the dependency for the Google services Gradle plugin 
  
 id 
  
 'com.google.gms.google-services' 
  
 version 
  
 '4.4.3' 
  
 apply 
  
 false 
 }

      2. In your module (app-level)Gradle file (usually <project>/<app-module>/build.gradle.kts or <project>/<app-module>/build.gradle ), add the Google services plugin:

        Kotlin 

         plugins 
  
 { 
  
 id 
 ( 
 "com.android.application" 
 ) 
  
  // Add the Google services Gradle plugin 
  
 id 
 ( 
 "com.google.gms.google-services" 
 ) 
  
 // ... 
 }

        Groovy 

         plugins 
  
 { 
  
 id 
  
 'com.android.application' 
  
  // Add the Google services Gradle plugin 
  
 id 
  
 'com.google.gms.google-services' 
  
 // ... 
 }

    Add Firebase SDKs to your app

    1. 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 Firebase Cloud Messaging library for Android. We recommend using the Firebase Android BoM to control library versioning.

      For an optimal experience with Firebase Cloud Messaging , we recommend enabling Google Analytics in your Firebase project and adding the Firebase SDK for Google Analytics to your app.

       dependencies 
  
 { 
  
  // Import the BoM 
for the Firebase platform 
  
 implementation 
 ( 
 platform 
 ( 
 "com.google.firebase:firebase-bom:34.2.0" 
 )) 
  
  // Add the dependencies for the Firebase Cloud Messaging 
and Analytics 
libraries 
  
 // When using the BoM 
, you don't specify versions in Firebase library dependencies 
  
  implementation 
 ( 
 "com.google.firebase:firebase-messaging" 
 ) 
  
 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 Firebase Cloud Messaging 
and Analytics 
libraries 
  
 // When NOT using the BoM 
, you must specify versions in Firebase library dependencies 
  
  implementation 
 ( 
 "com.google.firebase:firebase-messaging:25.0.0" 
 ) 
  
 implementation 
 ( 
 "com.google.firebase:firebase-analytics:23.0.0" 
 ) 
 }

    2. Sync your Android project with Gradle files.

      Are you getting a build failure about invoke-custom support and enabling desugaring? Here's how to fix it.

      Gradle builds that use Android Gradle plugin (AGP) v4.2 or earlier need to enable Java 8 support. Otherwise, these Android projects get a build failure when adding a Firebase SDK.

      To fix this build failure, you can follow one of two options:

      • Add the listed compileOptions from the error message to your app-level build.gradle.kts or build.gradle file.
      • Increase the minSdk for your Android project to 26 or above.

      Learn more about this build failure in this FAQ .

    Access the registration token

    To send a message to a specific device, you need to know that device's registration token. Because you'll need to enter the token in a field in the Notifications console to complete this tutorial, make sure to copy the token or securely store it after you retrieve it.

    On initial startup of your app, the FCM SDK generates a registration token for the client app instance. If you want to target single devices or create device groups, you'll need to access this token by extending FirebaseMessagingService and overriding onNewToken . Because the token could be rotated after initial startup, you are strongly recommended to retrieve the latest updated registration token.

    The registration token may change when:

    • The app is restored on a new device
    • The user uninstalls/reinstall the app
    • The user clears app data.

    Retrieve the current registration token

    When you need to retrieve the current token, call FirebaseMessaging.getInstance().getToken() :

    Kotlin 

     FirebaseMessaging 
 . 
 getInstance 
 (). 
 token 
 . 
 addOnCompleteListener 
 ( 
 OnCompleteListener 
  
 { 
  
 task 
  
 - 
>  
 if 
  
 ( 
 ! 
 task 
 . 
 isSuccessful 
 ) 
  
 { 
  
 Log 
 . 
 w 
 ( 
 TAG 
 , 
  
 "Fetching FCM registration token failed" 
 , 
  
 task 
 . 
 exception 
 ) 
  
 return 
 @OnCompleteListener 
  
 } 
  
 // Get new FCM registration token 
  
 val 
  
 token 
  
 = 
  
 task 
 . 
 result 
  
 // Log and toast 
  
 val 
  
 msg 
  
 = 
  
 getString 
 ( 
 R 
 . 
 string 
 . 
 msg_token_fmt 
 , 
  
 token 
 ) 
  
 Log 
 . 
 d 
 ( 
 TAG 
 , 
  
 msg 
 ) 
  
 Toast 
 . 
 makeText 
 ( 
 baseContext 
 , 
  
 msg 
 , 
  
 Toast 
 . 
 LENGTH_SHORT 
 ). 
 show 
 () 
 })

    Java 

     FirebaseMessaging 
 . 
 getInstance 
 (). 
 getToken 
 () 
  
 . 
 addOnCompleteListener 
 ( 
 new 
  
 OnCompleteListener<String> 
 () 
  
 { 
  
 @Override 
  
 public 
  
 void 
  
 onComplete 
 ( 
 @NonNull 
  
 Task<String> 
  
 task 
 ) 
  
 { 
  
 if 
  
 ( 
 ! 
 task 
 . 
 isSuccessful 
 ()) 
  
 { 
  
 Log 
 . 
 w 
 ( 
 TAG 
 , 
  
 "Fetching FCM registration token failed" 
 , 
  
 task 
 . 
 getException 
 ()); 
  
 return 
 ; 
  
 } 
  
 // Get new FCM registration token 
  
 String 
  
 token 
  
 = 
  
 task 
 . 
 getResult 
 (); 
  
 // Log and toast 
  
 String 
  
 msg 
  
 = 
  
 getString 
 ( 
 R 
 . 
 string 
 . 
 msg_token_fmt 
 , 
  
 token 
 ); 
  
 Log 
 . 
 d 
 ( 
 TAG 
 , 
  
 msg 
 ); 
  
 Toast 
 . 
 makeText 
 ( 
 MainActivity 
 . 
 this 
 , 
  
 msg 
 , 
  
 Toast 
 . 
 LENGTH_SHORT 
 ). 
 show 
 (); 
  
 } 
  
 });

    Monitor token generation

    The onNewToken callback fires whenever a new token is generated.

    Kotlin 

     /** 
 * Called if the FCM registration token is updated. This may occur if the security of 
 * the previous token had been compromised. Note that this is called when the 
 * FCM registration token is initially generated so this is where you would retrieve the token. 
 */ 
 override 
  
 fun 
  
 onNewToken 
 ( 
 token 
 : 
  
 String 
 ) 
  
 { 
  
 Log 
 . 
 d 
 ( 
 TAG 
 , 
  
 "Refreshed token: 
 $ 
 token 
 " 
 ) 
  
 // If you want to send messages to this application instance or 
  
 // manage this apps subscriptions on the server side, send the 
  
 // FCM registration token to your app server. 
  
 sendRegistrationToServer 
 ( 
 token 
 ) 
 } 
 
      MyFirebaseMessagingService 
 . 
 kt

    Java 

     /** 
 * There are two scenarios when onNewToken is called: 
 * 1) When a new token is generated on initial app startup 
 * 2) Whenever an existing token is changed 
 * Under #2, there are three scenarios when the existing token is changed: 
 * A) App is restored to a new device 
 * B) User uninstalls/reinstalls the app 
 * C) User clears app data 
 */ 
 @Override 
 public 
  
 void 
  
 onNewToken 
 ( 
 @NonNull 
  
 String 
  
 token 
 ) 
  
 { 
  
 Log 
 . 
 d 
 ( 
 TAG 
 , 
  
 "Refreshed token: " 
  
 + 
  
 token 
 ); 
  
 // If you want to send messages to this application instance or 
  
 // manage this apps subscriptions on the server side, send the 
  
 // FCM registration token to your app server. 
  
 sendRegistrationToServer 
 ( 
 token 
 ); 
 } 
 
      MyFirebaseMessagingService 
 . 
 java

    After you've obtained the token, you can send it to your app server and store it using your preferred method.

    Send a test notification message

    1. Install and run the app on the target device. On Apple devices, you'll need to accept the request for permission to receive remote notifications.

    2. Make sure the app is in the background on the device.

    3. In the Firebase console, open the Messaging page .

    4. If this is your first message, select Create your first campaign.

      1. Select Firebase Notification messagesand select Create.

    5. Otherwise, on the Campaignstab, select New campaignand then Notifications.

    6. Enter the message text. All other fields are optional.

    7. Select Send test messagefrom the right pane.

    8. In the field labeled Add an FCM registration token, enter the registration token you obtained in a previous section of this guide.

    9. Select Test.

    After you select Test, the targeted client device (with the app in the background) should receive the notification.

    For insight into message delivery to your app, see the FCM reporting dashboard , which records the number of messages sent and opened on Apple and Android devices, along with data for "impressions" (notifications seen by users) for Android apps.

    Next steps

    Send messages to foregrounded apps

    Once you have successfully sent notification messages while your app is in the background, see Receive Messages in an Android App to get started sending to foregrounded apps.

    Go beyond notification messages

    To go beyond notification messages and add other, more advanced behavior to your app, see:

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