Overview

iOS push notifications are essential for driving sustained user engagement and retention in your iOS 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. By integrating OneSignal’s SDK with your app, you can take advantage of Apple Push Notification Service (APNS) to ensure your notifications are delivered seamlessly across iOS devices. This guide will walk you through integrating our SDK into your iOS app.


Requirements

  • macOS with Xcode 14+ (setup instructions use Xcode 16.2)
  • Device with iOS 12+, iPadOS 12+, or Xcode simulator running iOS 16.2+
  • 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.


iOS setup

Follow these steps to add push notifications to your iOS app, including support for Badges, Confirmed Delivery, and images.

1. Add Push Notifications capability to app target

The Push Notifications capability allows your app to register a push token and receive notifications.

  1. Open your app’s .xcworkspace file in Xcode.
  2. Select your app target > Signing & Capabilities
  3. Click + Capability and add Push Notifications capability

The app target is given Push Notifications capability.

2. Add Background Modes capability to app target

This enables your app to wake in the background when push notifications arrive.

  1. Add Background Modes capability
  2. Enable Remote notifications

The app target is given Remote Notifications background execution mode.

3. Add app target to App Group

App Groups allow data sharing between your app and the Notification Service Extension. Required for Confirmed Delivery and Badges.

  1. Add App Groups capability
  2. In the App Groups capability click +
  3. Add a new container ID in format: group.your_bundle_id.onesignal
  • Keep group. and .onesignal prefix and suffix. Replace your_bundle_id with your app’s bundle identifier.
  • For example, bundle identifier com.onesignal.MyApp, will have the container name group.com.onesignal.MyApp.onesignal.

The app target is part of the App Group.

Your App Group name must exactly match your bundle ID’s spelling and capitalization across all targets.

4. Add Notification Service Extension

The Notification Service Extension (NSE) enables rich notifications and Confirmed Delivery analytics.

  1. In Xcode: File > New > Target…
  2. Select Notification Service Extension, then Next.
  3. Set the product name to OneSignalNotificationServiceExtension and press Finish.
  4. Press Don’t Activate on the Activate scheme prompt.

Select the Notification Service Extension target.

Name the Notification Service Extension .

Cancel activation to continue debugging your app target.

Set the OneSignalNotificationServiceExtension Minimum Deployment Target to match your main app (iOS 15+ recommended).

If you’re using CocoaPods, set the deployment version in your Podfile as well.

Set the same deployment target as the main app.

5. Add NSE target to app group

Use the same App Group ID you added in step 3.

  1. Go to OneSignalNotificationServiceExtension > Signing & Capabilities
  2. Add App Groups
  3. Add the exact same group ID

The NSE now belongs to the same app group as your app target.

6. Update NSE code

  1. Navigate to the OneSignalNotificationServiceExtension folder
  2. Replace the contents of the NotificationService.swift or NotificationService.m file with the following:

Navigate to your NotificationService file.

import UserNotifications
import OneSignalExtension

class NotificationService: UNNotificationServiceExtension {
    var contentHandler: ((UNNotificationContent) -> Void)?
    var receivedRequest: UNNotificationRequest!
    var bestAttemptContent: UNMutableNotificationContent?

    // Note this extension only runs when `mutable_content` is set
    // Setting an attachment or action buttons automatically sets the property to true
    override func didReceive(_ request: UNNotificationRequest, withContentHandler contentHandler: @escaping (UNNotificationContent) -> Void) {
        self.receivedRequest = request
        self.contentHandler = contentHandler
        self.bestAttemptContent = (request.content.mutableCopy() as? UNMutableNotificationContent)

        if let bestAttemptContent = bestAttemptContent {
            // DEBUGGING: Uncomment the 2 lines below to check this extension is executing
//            print("Running NotificationServiceExtension")
//            bestAttemptContent.body = "[Modified] " + bestAttemptContent.body

            OneSignalExtension.didReceiveNotificationExtensionRequest(self.receivedRequest, with: bestAttemptContent, withContentHandler: self.contentHandler)
        }
    }

    override func serviceExtensionTimeWillExpire() {
        // Use this as an opportunity to deliver your "best attempt" at modified content, otherwise the original push payload will be used.
        if let contentHandler = contentHandler, let bestAttemptContent =  bestAttemptContent {
            OneSignalExtension.serviceExtensionTimeWillExpireRequest(self.receivedRequest, with: self.bestAttemptContent)
            contentHandler(bestAttemptContent)
        }
    }
}

You should see an error because the OneSignal package is not installed. This will be resolved in the next step.

This file shows an error until you install the package in the next step.


SDK setup

This section will guide you through integrating OneSignal’s core features. By the end of this section, you will have a basic integration with our SDK enabling you to trigger in-app messages and receive push notifications.

1. Add SDK

Add our SDK using Xcode Package Dependencies Manager or CocoaPods. There are 4 available libraries. If you do not want In-app messages and/or Location tracking, you can omit these packages.

LibraryTargetRequired
OneSignalExtensionOneSignalNotificationServiceExtension
OneSignalFrameworkApp
OneSignalInAppMessagesAppRecommended
OneSignalLocationAppOptional

Add the OneSignal dependencies

Navigate to File > Add Package Dependencies… and enter the URL to the OneSignal iOS SDK repository:

https://github.com/OneSignal/OneSignal-iOS-SDK

Select the onesignal-ios-sdk package and click Add Package.

Choose Package Products for OneSignal-iOS-SDK.

  • Important: Add the OneSignalExtension to the OneSignalNotificationServiceExtension Target.
  • Add the OneSignalFramework to your App Target.
  • If you plan on using in-app messages (recommended) and/or location tracking, then add those packages to your App Target as well.

If your app doesn't require location tracking, you can remove the package as shown in this example.

For more details, see Apple’s Adding package dependencies doc.

2. Initialize SDK

Depending on your Xcode interface setup, initialize OneSignal following these options.

Add the initialization code

If using SwiftUI interface, navigate to your <APP_NAME>App.swift file and initialize OneSignal with the provided methods.

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

import SwiftUI
import OneSignalFramework

@main
struct YOURAPP_NAME: App {
  //Connect the SwiftUI app to the UIKit app delegate
    @UIApplicationDelegateAdaptor(AppDelegate.self) var appDelegate
    
    var body: some Scene {
        WindowGroup {
            ContentView()
        }
    }
}

class AppDelegate: NSObject, UIApplicationDelegate {
    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey : Any]? = nil) -> Bool {
      
       // Enable verbose logging for debugging (remove in production)
       OneSignal.Debug.setLogLevel(.LL_VERBOSE)     
       // Initialize with your OneSignal App ID
       OneSignal.initialize("YOUR_APP_ID", withLaunchOptions: launchOptions)
       // 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.
       OneSignal.Notifications.requestPermission({ accepted in
         print("User accepted notifications: \(accepted)")
       }, fallbackToSettings: false)
      
       return true
    }
}

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

1

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

2

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

3

Return to the app and tap Allow on the prompt.

4

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.

1

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

2

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

3

Create a test users segment.

Go to Audience > Segments > New Segment.

4

Name the segment.

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

5

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

1

Get your App API Key and App ID.

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

2

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"
}'
3

Run the code.

Run the code in your terminal.

4

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.
5

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.

1

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.

2

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

3

Customize the message content if desired.

Example customization of in-app Welcome message

4

Set Trigger to 'On app open'.

5

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

6

Make message live.

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

7

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:

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.

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:

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

For full customization, see Mobile Service Extensions.

User state changes

In-app message events


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.

Need help?

Chat with our Support team or email support@onesignal.com

Please 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!