Android SDK setup

Overview

Android push notifications are essential for driving sustained user engagement and retention in your Android app. They empower you to deliver real-time updates, reminders, and personalized messages directly to your users, improving the overall user experience and stickiness of your app. OneSignal leverages Firebase Cloud Messaging (FCM) but is designed to provide even more flexibility and functionality as shown in this guide.

Requirements

Android 7.0+ device or emulator with “Google Play Store (Services)” installed.
Android Studio (setup instructions use Android Studio Meerkat).
Configured OneSignal app and platform.

Configure your OneSignal app and platform

Required setup for push notifications To start sending push notifications with OneSignal, you must first configure your OneSignal app with all the platforms your support—Apple (APNs), Google (FCM), Huawei (HMS), and/or Amazon (ADM).

If your organization already has a OneSignal account, ask to be invited as an admin role to configure the app. Otherwise, sign up for a free account to get started.

Step-by-step instructions for configuring your OneSignal app.

Android setup

1. Add the OneSignal SDK

In Android Studio, open your build.gradle.kts (Module: app) or build.gradle (Module: app) file and add OneSignal to your dependencies.

implementation("com.onesignal:OneSignal:[5.1.6, 5.1.99]")

Example shows adding OneSignal to your App's build.gradle.kts file.

Sync Gradle

After adding the dependency, sync your project:

Click Sync Now in the banner
Or go to File > Sync Project with Gradle Files

2. Initialize SDK in the Application class

It’s best practice to initialize OneSignal in the onCreate method of your Application class to ensure proper SDK setup across all entry points.

How to create an Application class

Create a new class (example: ApplicationClass) and add the following code.

package com.your.package.name // Replace with your package name
import android.app.Application

class ApplicationClass : Application() {
  override fun onCreate() {
    super.onCreate()
    // OneSignal initialization will go here
  }
}

Example ApplicationClass.kt file.

Open your app’s AndroidManifest.xmlIn your <application> tag add android:name=".ApplicationClass" (replace .ApplicationClass with your actual class name if set it to something different).

xml

  <manifest xmlns:android="http://schemas.android.com/apk/res/android"
      xmlns:tools="http://schemas.android.com/tools">
    
     <application
          android:name=".ApplicationClass"
          android:icon="@mipmap/ic_launcher"
          android:label="@string/app_name"
          ...
      </application>
    
  </manifest>

AndroidManifest.xml with the .ApplicationClass name.

In your ApplicationClass, initialize OneSignal with the provided methods. Replace YOUR_APP_ID with your OneSignal App ID found Settings > Keys & IDs in your OneSignal dashboard. If you don’t have access to the OneSignal app, ask your Team Members to invite you.

package com.your.package.name // Replace with your package name

import android.app.Application
import kotlinx.coroutines.CoroutineScope
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.launch

import com.onesignal.OneSignal
import com.onesignal.debug.LogLevel
  
class ApplicationClass : Application() {
   override fun onCreate() {
      super.onCreate()
        
      // Enable verbose logging for debugging (remove in production)
      OneSignal.Debug.logLevel = LogLevel.VERBOSE
      // Initialize with your OneSignal App ID
      OneSignal.initWithContext(this, "YOUR_APP_ID")
      // Use this method to prompt for push notifications.
      // We recommend removing this method after testing and instead use In-App Messages to prompt for notification permission.
      CoroutineScope(Dispatchers.IO).launch {
         OneSignal.Notifications.requestPermission(true)
      }
   }
}

ApplicationClass.kt file with OneSignal code added.

Initializing in an Activity (like MainActivity) is not recommended because it may not be called on app cold-starts from deep links or notifications. Always initialize OneSignal in your Application class for reliability.

3. Customize default icons

We recommend configuring your notification icons to match your app’s branding. Otherwise, OneSignal will use a default bell icon.

Testing the OneSignal SDK integration

This guide helps you verify that your OneSignal SDK integration is working correctly by testing push notifications, subscription registration, and in-app messaging.

Check mobile subscriptions

Launch your app on a test device.

The native push permission prompt should appear automatically if you added the requestPermission method during initialization.

iOS and Android push permission prompts

Check your OneSignal dashboard

Before accepting the prompt, check the OneSignal dashboard:

Go to Audience > Subscriptions.
You should see a new entry with the status “Never Subscribed”.

Dashboard showing subscription with 'Never Subscribed' status

Return to the app and tap Allow on the prompt.

Refresh the OneSignal dashboard Subscription's page.

The subscription’s status should now show Subscribed.

Dashboard showing subscription with 'Subscribed' status

You have successfully created a mobile subscription. Mobile subscriptions are created when users first open your app on a device or if they uninstall and reinstall your app on the same device.

Set up test subscriptions

Test subscriptions are helpful for testing a push notification before sending a message.

Add to Test Subscriptions.

In the dashboard, next to the subscription, click the Options (three dots) button and select Add to Test Subscriptions.

Adding a device to Test Subscriptions

Name your subscription.

Name the subscription so you can easily identify your device later in the Test Subscriptions tab.

Dashboard showing the 'Name your subscription' field

Create a test users segment.

Go to Audience > Segments > New Segment.

Name the segment.

Name the segment Test Users (the name is important because it will be used later).

Add the Test Users filter and click Create Segment.

Creating a 'Test Users' segment with the Test Users filter

You have successfully created a segment of test users. We can now test sending messages to this individual device and groups of test users.

Send test push via API

Get your App API Key and App ID.

In your OneSignal dashboard, go to Settings > Keys & IDs.

Update the provided code.

Replace YOUR_APP_API_KEY and YOUR_APP_ID in the code below with your actual keys. This code uses the Test Users segment we created earlier.

curl -X \
POST --url 'https://api.onesignal.com/notifications' \
 --header 'content-type: application/json; charset=utf-8' \
 --header 'authorization: Key YOUR_APP_API_KEY' \
 --data \
 '{
  "app_id": "YOUR_APP_ID",
  "target_channel": "push",
  "name": "Testing basic setup",
  "headings": {
  	"en": "👋"
  },
  "contents": {
    "en": "Hello world!"
  },
  "included_segments": [
    "Test Users"
  ],
  "ios_attachments": {
    "onesignal_logo": "https://avatars.githubusercontent.com/u/11823027?s=200&v=4"
  },
  "big_picture": "https://avatars.githubusercontent.com/u/11823027?s=200&v=4"
}'

Run the code.

Run the code in your terminal.

Check images and confirmed delivery.

If all setup steps were completed successfully, the test subscriptions should receive a notification with an image included:

Push notification with image on iOS and Android

Images will appear small in the collapsed notification view. Expand the notification to see the full image.

Check for confirmed delivery.

In your dashboard, go to Delivery > Sent Messages, then click the message to view stats.You should see the confirmed stat, meaning the device received the push.

Delivery stats showing confirmed delivery

If you’re on a Professional plan or higher, scroll to Audience Activity to see subscription-level confirmation:

Confirmed delivery at the device level in Audience Activity

You have successfully sent a notification via our API to a segment.

No image received? Your Notification Service Extension might be missing.
No confirmed delivery? Review your App Groups setup.
Having issues? Copy-paste the api request and a log from start to finish of app launch into a .txt file. Then share both with support@onesignal.com.

Send an in-app message

In-app messages let you communicate with users while they are using your app.

Close or background your app on the device.

This is because users must meet the in-app audience criteria before a new session starts. In OneSignal, a new session starts when the user opens your app after it has been in the background or closed for at least 30 seconds. For more details, see our guide on how in-app messages are displayed.

Create an in-app message.

In your OneSignal dashboard, navigate to Messages > In-App > New In-App.
Find and select the Welcome message.
Set your Audience as the Test Users segment we used previously.

Targeting the 'Test Users' segment with an in-app message

Customize the message content if desired.

Example customization of in-app Welcome message

Set Trigger to 'On app open'.

Schedule frequency.

Under Schedule > How often do you want to show this message? select Every time trigger conditions are satisfied.

In-app message scheduling options

Make message live.

Click Make Message Live so it is available to your Test Users each time they open the app.

Open the app and see the message.

After the in-app message is live, open your app. You should see it display:

Welcome in-app message shown on devices

Not seeing the message?

Start a new session
- You must close or background the app for at least 30 seconds before reopening. This ensures a new session is started.
- For more, see how in-app messages are displayed.
Still in the Test Users segment?
- If you reinstalled or switched devices, re-add the device to Test Subscriptions and confirm it’s part of the Test Users segment.
Having issues?
- Follow Getting a Debug Log while reproducing the steps above. This will generate additional logging that you can share with support@onesignal.com and we will help investigate what’s going on.

You have successfully setup the OneSignal SDK and learned important concepts like:

Gathering Subscriptions, setting Test subscriptions, and creating Segments.
Sending Push with images and Confirmed Delivery using Segments and our Create message API.
Sending In-app messages.

Continue with this guide to identify users in your app and setup additional features.

User identification

Previously, we demonstrated how to create mobile Subscriptions. Now we’ll expand to identifying Users across all their subscriptions (including push, email, and SMS) using the OneSignal SDK. We’ll cover External IDs, tags, multi-channel subscriptions, privacy, and event tracking to help you unify and engage users across platforms.

Assign External ID

Use an External ID to identify users consistently across devices, email addresses, and phone numbers using your backend’s user identifier. This ensures your messaging stays unified across channels and 3rd party systems (especially important for Integrations). Set the External ID with our SDK’s login method each time they are identified by your app.

OneSignal generates unique read-only IDs for subscriptions (Subscription ID) and users (OneSignal ID).As users download your app on different devices, subscribe to your website, and/or provide you email addresses and phone numbers outside of your app, new subscriptions will be created.Setting the External ID via our SDK is highly recommended to identify users across all their subscriptions, regardless of how they are created.

Add data tags

Tags are key-value pairs of string data you can use to store user properties (like username, role, or preferences) and events (like purchase_date, game_level, or user interactions). Tags power advanced Message Personalization and Segmentation allowing for more advanced use cases. Set tags with our SDK addTag and addTags methods as events occur in your app. In this example, the user reached level 6 identifiable by the tag called current_level set to a value of 6.

A user profile in OneSignal with a tag called "current_level" set to "6"

We can create a segment of users that have a level of between 5 and 10, and use that to send targeted and personalized messages:

Segment editor showing a segment targeting users with a current_level value of greater than 4 and less than 10

Screenshot showing a push notification targeting the Level 5-10 segment with a personalized message

The push notification is received on an iOS and Android device with the personalized content

Add email and/or SMS subscriptions

Earlier we saw how our SDK creates mobile subscriptions to send push and in-app messages. You can also reach users through emails and SMS channels by creating the corresponding subscriptions.

Use the addEmail method to create email subscriptions.
Use the addSms method to create SMS subscriptions.

If the email address and/or phone number already exist in the OneSignal app, the SDK will add it to the existing user, it will not create duplicates. You can view unified users via Audience > Users in the dashboard or with the View user API.

A user profile with push, email, and SMS subscriptions unified by External ID

Best practices for multi-channel communication

Obtain explicit consent before adding email or SMS subscriptions.
Explain the benefits of each communication channel to users.
Provide channel preferences so users can select which channels they prefer.

To control when OneSignal collects user data, use the SDK’s consent gating methods:

setConsentRequired(true): Prevents data collection until consent is given.
setConsentGiven(true): Enables data collection once consent is granted.

See our Privacy & security docs for more on:

Prompt for push permissions

Instead of calling requestPermission() immediately on app open, take a more strategic approach. Use an in-app message to explain the value of push notifications before requesting permission. For best practices and implementation details, see our Prompt for push permissions guide.

Listen to push, user, and in-app events

Use SDK listeners to react to user actions and state changes. The SDK provides several event listeners for you to hook into. See our SDK reference guide for more details.

Push notification events

addClickListener(): Detect when a notification is tapped. Helpful for Deep Linking.
addForegroundLifecycleListener(): Control how notifications behave in foreground.

For full customization, see Mobile Service Extensions.

User state changes

addObserver() for user state: Detect when the External ID is set.
addPermissionObserver(): Track the user’s specific interaction with the native push permission prompt.
addObserver() for push subscription: Track when the push subscription status changes.

In-app message events

addClickListener(): Handle in-app click actions. Ideal for deep linking or tracking events.
addLifecycleListener(): Track full lifecycle of in-app messages (shown, clicked, dismissed, etc.).

Advanced setup & capabilities

Explore more capabilities to enhance your integration:

Mobile SDK setup & reference

Make sure you’ve enabled all key features by reviewing the Mobile push setup guide. For full details on available methods and configuration options, visit the Mobile SDK reference.

Congratulations! You’ve successfully completed the Mobile SDK setup guide.

Custom Notification Layout

Android 12 and higher enforce system templates for custom notifications. However, you can still customize your layout using Android’s standard notification styles.

Apps targeting Android 12+ can’t use fully custom layouts due to behavior changes. See Notification.DecoratedCustomViewStyle for available customizations.

To customize your layout:

Follow Android’s custom notification guide
Apply changes via the Notification Service Extension

Disable default open behavior

When a notification is clicked, OneSignal will resume your app, or open your launcher Activity if your app was swiped away. To prevent OneSignal from auto-opening your launcher Activity when a notification is clicked, add this to your AndroidManifest.xml:

AndroidManifest.xml

  <application ...>
     <meta-data android:name="com.onesignal.NotificationOpened.DEFAULT" android:value="DISABLE" />
  </application>

You must implement a custom Notification Opened Listener in the onCreate method in your Application class. You will need to call startActivity from this callback to take the user to your intended Activity.

Background data and push overrides

Use the Notification Service Extension to handle background data or override notification visuals
Use the SDK Notification Event Handlers to read additional data from a notification

Right-to-Left (RTL) language support

To support RTL languages in notifications and UI, add this to your AndroidManifest.xml:

AndroidManifest.xml

  <application
    android:supportsRtl="true"
    ...
  </application>

Make sure to test all Activities and views to verify correct RTL behavior. See Android’s documentation on localizing your app for more information.

Need help?Chat with our Support team or email support@onesignal.comPlease include:

Details of the issue you’re experiencing and steps to reproduce if available
Your OneSignal App ID
The External ID or Subscription ID if applicable
The URL to the message you tested in the OneSignal Dashboard if applicable
Any relevant logs or error messages

We’re happy to help!

Developer Documentation

Mobile SDKs

Web SDKs

Live Activities

Desktop & Watch Setup

Legacy SDK reference

Overview

Requirements

Configure your OneSignal app and platform

Android setup

1. Add the OneSignal SDK

Sync Gradle

2. Initialize SDK in the Application class

3. Customize default icons

Testing the OneSignal SDK integration

Check mobile subscriptions

Set up test subscriptions

Send test push via API

Send an in-app message

User identification

Assign External ID

Add data tags

Add email and/or SMS subscriptions

Prompt for push permissions

Listen to push, user, and in-app events

Push notification events

User state changes

In-app message events

Advanced setup & capabilities

Mobile SDK setup & reference

Custom Notification Layout

Disable default open behavior

Background data and push overrides

Right-to-Left (RTL) language support

Developer Documentation

Mobile SDKs

Web SDKs

Live Activities

Desktop & Watch Setup

Legacy SDK reference

​Overview

​Requirements

​Configure your OneSignal app and platform

​Android setup

​1. Add the OneSignal SDK

​Sync Gradle

​2. Initialize SDK in the Application class

​3. Customize default icons

​Testing the OneSignal SDK integration

​Check mobile subscriptions

​Set up test subscriptions

​Send test push via API

​Send an in-app message

​User identification

​Assign External ID

​Add data tags

​Add email and/or SMS subscriptions

​Privacy & user consent

​Prompt for push permissions

​Listen to push, user, and in-app events

​Push notification events

​User state changes

​In-app message events

​Advanced setup & capabilities

​Mobile SDK setup & reference

​Custom Notification Layout

​Disable default open behavior

​Background data and push overrides

​Right-to-Left (RTL) language support

Overview

Requirements

Configure your OneSignal app and platform

Android setup

1. Add the OneSignal SDK

Sync Gradle

2. Initialize SDK in the Application class

3. Customize default icons

Testing the OneSignal SDK integration

Check mobile subscriptions

Set up test subscriptions

Send test push via API

Send an in-app message

User identification

Assign External ID

Add data tags

Add email and/or SMS subscriptions

Privacy & user consent

Prompt for push permissions

Listen to push, user, and in-app events

Push notification events

User state changes

In-app message events

Advanced setup & capabilities

Mobile SDK setup & reference

Custom Notification Layout

Disable default open behavior

Background data and push overrides

Right-to-Left (RTL) language support