Mobile SDK reference

Comprehensive API reference for the OneSignal Mobile SDK, including initialization, user identity, subscriptions, tags, permissions, in-app messages, live activities, and more. Supports Android, iOS, Unity, React Native, Flutter, and Cordova/Ionic platforms.

Setup & debugging

These methods are a reference for integrating the OneSignal SDK into your app. For full platform-specific setup instructions, see Mobile SDK setup.

initialize()

Initializes the OneSignal SDK. This should be called during application startup. The ONESIGNAL_APP_ID can be found in Keys & IDs.

If you want to delay initialization of the OneSignal SDK, we recommend using our Privacy methods.

Kotlin

OneSignal.initWithContext(this, ONESIGNAL_APP_ID)

setLogLevel()

Set the logging to print additional logs to Android LogCat or Xcode logs. Call this before initializing OneSignal. See Getting a Debug Log for more details.

Log levels (least to most verbose): None | Fatal | Error | Warn | Info | Debug | Verbose. Cordova/Ionic uses integers 0–6.

Kotlin

OneSignal.Debug.logLevel = LogLevel.Verbose

setAlertLevel()

Sets the logging level to show as alert dialogs in your app. Make sure to remove this before submitting to the app store.

Kotlin

OneSignal.Debug.alertLevel = LogLevel.Exception

User identity & properties

When users open your app, OneSignal automatically creates a OneSignal ID (User-level ID ID) and a Subscription ID (device-level ID). You can associate multiple Subscriptions (e.g., devices, emails, phone numbers) with a single user by calling login() with your unique user identifier.

login(external_id)

Links the current device (mobile Subscription) to a known user identified external_id. Call this only for identified users (after sign-in or session restore). For anonymous users, rely on the automatically assigned onesignal_id (see User State addObserver()).

If the external_id already exists: the SDK switches to the existing user, links the current mobile Subscription to it, and discards any anonymous data (tags, session data, email/SMS Subscriptions). A 409 Conflict log is expected and can be ignored.

If the external_id does not exist: a new user is created with the current onesignal_id, retaining all anonymous data.

The SDK retries automatically on network failures. Call login(external_id) every time the app starts once the user’s ID is known, and again on account switches.

Kotlin

OneSignal.login("external_id")

logout()

Unlinks the current user from the mobile Subscription.

• Removes the external_id from the current mobile Subscription. Does not remove the external_id from other Subscriptions.
• Resets the onesignal_id to a new anonymous user.
• Any new data (e.g tags, Subscriptions, session data, etc.) will now be set on the new anonymous user until they are identified with the login method.

Use this when a user signs out of your app and you do not want to send targeted transactional messages to the device anymore.

Kotlin

OneSignal.logout()

getOnesignalId()

Returns the current user-level onesignal_id from local device storage. It may return null before the SDK finishes initializing; use the User State addObserver() instead to reliably get the onesignal_id and react to changes.

Do not persist the OneSignal ID as a permanent user identifier. It can change when users log in, log out, or switch accounts.

Kotlin

val onesignalId = OneSignal.User.onesignalId

getExternalId()

Returns the current user-level external_id from local device storage. It may return null if not set via the login method or called before user state is initialized.

Kotlin

  val externalId = OneSignal.User.externalId

addEventListener() User State

Listen for changes in the user context (e.g., login, logout, ID assignment).

Kotlin

OneSignal.User.addObserver(object : IUserStateObserver {
    override fun onUserStateChange(state: UserChangedState) {
        println("User State Changed: onesignalId=${state.current.onesignalId}, externalId=${state.current.externalId}")
    }
})

addAlias(), addAliases(), removeAlias(), removeAliases()

Aliases are alternative identifiers (like usernames or CRM IDs). Set external_id with login() before adding aliases. Aliases added without an external_id will not sync across multiple Subscriptions.

Kotlin

// Add a single alias
OneSignal.User.addAlias("ALIAS_LABEL", "ALIAS_ID")

// Add multiple aliases
var aliases = mapOf("ALIAS_LABEL_01" to "ALIAS_ID_01", "ALIAS_LABEL_02" to "ALIAS_ID_02")
OneSignal.User.addAliases(aliases)

// Remove a single alias
OneSignal.User.removeAlias("ALIAS_LABEL")

// Remove multiple aliases
OneSignal.User.removeAliases(["ALIAS_LABEL_01", "ALIAS_LABEL_02"])

setLanguage()

Overrides the auto-detected language of the user. Use ISO 639-1 language code.

Kotlin

OneSignal.User.setLanguage("en")

---

Custom events

Track user actions with associated properties. See Custom Events for more details.

Custom events require the following minimum SDK versions: iOS 5.4.0, Android 5.6.1, React Native 5.3.0, Flutter 5.4.0, Unity 5.2.0.

Track and send a custom event performed by the current user.

• name - Required. The name of the event as a string.
• properties - Optional. Key-value pairs to add to the event. The properties dictionary or map must be serializable into a valid JSON Object. Supports nested values.

The SDK automatically includes app-specific data under the reserved os_sdk key in the properties payload (e.g., os_sdk.device_type).

Example os_sdk payload

{ 
  "os_sdk": { 
    "sdk": "050213", 
    "device_os": "18.5", 
    "type": "iOSPush", 
    "device_model": "iPhone14,4", 
    "device_type": "ios", 
    "app_version": "5.4.0" 
  }
}

trackEvent()

See Custom Events for more details.

Kotlin

OneSignal.User.trackEvent("my_event_name")

OneSignal.User.trackEvent(
   name = "started_free_trial",
   properties = mapOf(
       "promo_code" to "NEW50",
       "membership_details" to mapOf(
           "vip" to true,
           "products_viewed_count" to 15
       )
   )
)

Data tags

Tags are custom key : value pairs of string data you set on users based on events or user properties. See Data Tags for more details.

addTag(), addTags()

Set a single or multiple tags on the current user.

• Values will be replaced if the key already exists.
• Exceeding your plan’s tag limit will cause the operations to fail silently.

Kotlin

OneSignal.User.addTag("KEY", "VALUE")

OneSignal.User.addTags(mapOf("KEY_01" to "VALUE_01", "KEY_02" to "VALUE_02"))

removeTag(), removeTags()

Delete a single or multiple tags from the current user.

Kotlin

OneSignal.User.removeTag("KEY")

OneSignal.User.removeTags(listOf("KEY_01", "KEY_02"))

getTags()

Returns the local copy of the user’s tags. Tags are updated from the server during login() or new app sessions.

Kotlin

val tags: Map<String, String> = OneSignal.User.getTags()

---

Privacy

setConsentRequired()

Enforces user consent before data collection begins. Must be called before initializing the SDK.

Kotlin

OneSignal.consentRequired = true

setConsentGiven()

Grants or revokes user consent for data collection. Without consent, no data is sent to OneSignal and no subscription is created.

• If setConsentRequired() is true, our SDK will not be fully enabled until setConsentGiven is called with true.
• If setConsentGiven is set to true and a Subscription is created, then later it is set to false, that Subscription will no longer receive updates. The current data for that Subscription remains unchanged until setConsentGiven is set to true again.
• If you want to delete the User and/or Subscription data, use our Delete user or Delete subscription APIs.

Kotlin

OneSignal.consentGiven = true

---

Location

Tracking location points requires 3 steps:

1. Add location tracking permissions and dependencies to your app.

• iOS: Choosing the Location Services Authorization to Request developer guide
• Android: Request location permissions developer guide

You may get the following errors:

LocationManager.startGetLocation: not possible, no location dependency found

Check your App’s dependencies. A common solutions is in you app/build.gradle add: implementation 'com.google.android.gms:play-services-location:21.0.1'

2. Enable your app to share location with OneSignal using the Location.setShared() method.
3. Request permission from the user for location tracking with the Location.requestPermission method or use in-app messages.

setShared() Location

Enables or checks whether the SDK is sharing the Subscription’s latitude and longitude with OneSignal. Set proper location permissions first.

Kotlin

OneSignal.Location.isShared = true

var isShared: Boolean = OneSignal.isShared

requestPermission() Location

Displays the system-level location permission prompt. Alternatively, use in-app messages. Requires proper location permissions and setShared(true).

Kotlin

OneSignal.Location.requestPermission(true)

---

Subscriptions

A Subscription represents a single messaging channel instance (for example, a mobile device) and has a unique Subscription ID (OneSignal’s device-level ID). A user can have multiple Subscriptions across devices and platforms.

See Subscriptions for more details.

User.pushSubscription.id

Returns the current device-level subscription_id from local device storage. It may return null before the SDK finishes initializing; use the Push Subscription addObserver() instead to reliably get the subscription_id and react to changes.

Kotlin

val subscriptionId = OneSignal.User.pushSubscription.id

User.pushSubscription.token

Returns the current device-level push subscription token from local device storage. It may return null before the SDK finishes initializing or the token isn’t available yet; use the Push Subscription addObserver() instead to reliably get the token and react to changes.

Kotlin

val pushToken = OneSignal.User.pushSubscription.token

addObserver() Push Subscription Changes

Use this method to respond to mobile Subscription changes like:

• The device receives a new push token from Google (FCM) or Apple (APNs)
• OneSignal assigns a subscription ID
• The optedIn value changes (e.g. called optIn() or optOut())
• The user toggles push permission in system settings, then opens the app

When this happens, the SDK triggers the onPushSubscriptionChange event. Your listener receives a state object with the previous and current values so you can detect exactly what changed.

To stop listening for updates, call the associated removeObserver() or removeEventListener() method.

Kotlin

class MyObserver : IPushSubscriptionObserver {
  init {
    OneSignal.User.pushSubscription.addObserver(this)
  }

  override fun onPushSubscriptionChange(state: PushSubscriptionChangedState) {
    if (state.current.optedIn) {
      println("User is now opted-in with push token: ${state.current.token}")
    }
  }
}

// Remove the observer
OneSignal.User.pushSubscription.removeObserver(this)

optOut(), optIn(), optedIn

Control the subscription status (subscribed or unsubscribed) of the current mobile Subscription within your app. Common use cases:

• Call optOut() after logout() to prevent push from being sent to users that log out. Call optIn() to resume push notifications.

• Implement a notification preference center within your app.

• optOut(): Sets the current push subscription status to unsubscribed (even if the user has a valid push token).

• optIn(): Does one of three actions:

  1. If the Subscription has a valid push token, it sets the current push subscription status to subscribed.
  2. If the Subscription does not have a valid push token, it displays the push permission prompt.
  3. If the push permission prompt has been displayed more than the operating system’s limit (once iOS, twice Android), it displays the fallback prompt.

• optedIn: Returns true if the current push subscription status is subscribed, otherwise false. If the push token is valid but optOut() was called, this will return false.

Kotlin

OneSignal.User.pushSubscription.optOut()

OneSignal.User.pushSubscription.optIn()

val optedIn = OneSignal.User.pushSubscription.optedIn

addEmail(), removeEmail()

Adds or removes an email Subscription for the current user. Compatible with Identity Verification.

• addEmail(email) creates or reassigns the email Subscription to the current user. The same email cannot exist multiple times in one app.
• removeEmail(email) detaches the email from the current user and assigns it a new OneSignal ID. Other Subscriptions remain unaffected.

Status code	Meaning
200 OK	The Subscription already belongs to the current user.
201 Created	A new Subscription was created and linked to the user.
202 Accepted	The Subscription already existed and was moved to the current user.

Call login() before addEmail() to avoid attaching it to an anonymous user. See Email reputation best practices.

Kotlin

OneSignal.User.addEmail("[e-mail]")

OneSignal.User.removeEmail("[e-mail]")

addSms(), removeSms()

Adds or removes an SMS Subscription for the current user. Phone numbers must be in E.164 format (e.g., [phone]). Compatible with Identity Verification.

• addSms(phoneNumber) creates or reassigns the SMS Subscription to the current user. The same number cannot exist multiple times in one app.
• removeSms(phoneNumber) detaches the number from the current user and assigns it a new OneSignal ID. Other Subscriptions remain unaffected.

Returns the same status codes as addEmail(). Call login() before addSms() to avoid attaching it to an anonymous user. See SMS Registration Requirements.

Kotlin

OneSignal.User.addSms("[phone]")

OneSignal.User.removeSms("[phone]")

---

Push permissions

requestPermission(fallbackToSettings) Push

Shows the native system prompt asking the user for push notification permission. Optionally enable a fallback prompt that links to the settings app.

• fallbackToSettings: If true, the fallback prompt will be displayed if the user denied push permissions more than the operating system’s limit (once iOS, twice Android).

For production apps, consider using In-App Messages to prompt for notification permission instead of calling this method directly.

Kotlin

OneSignal.Notifications.requestPermission(true)

addPermissionObserver() Push

Fires when push permission changes — the user accepts/declines the prompt, or toggles notifications in system settings. The listener receives a state object with from and to values. Call removePermissionObserver() to stop listening.

Kotlin

class MyObserver : IPermissionObserver {
  init {
    OneSignal.Notifications.addPermissionObserver(this)
  }

  override fun onNotificationPermissionChange(granted: Boolean) {
    if (granted) {
      // Notifications are now enabled
    }
  }

  fun cleanup() {
    OneSignal.Notifications.removePermissionObserver(this)
  }
}

getPermission(), getCanRequestPermission()

getPermission() returns the current app-level push permission status. It does not reflect OneSignal-level changes from optOut() or the Subscriptions API. For real-time tracking, use the Push Permission Observer or Push Subscription Observer.

getCanRequestPermission() returns whether the system will show a permission prompt. If false, the user already denied permission. See Prompt for push permissions.

Kotlin

// getPermission
OneSignal.Notifications.permission

// getCanRequestPermission
val canRequest: Boolean = OneSignal.Notifications.canRequestPermission

permissionNative iOS

Returns an enum for the native permission of the iOS device. It will be one of:

• 0 = NotDetermined
• 1 = Denied
• 2 = Authorized
• 3 = Provisional (only available in iOS 12+)
• 4 = Ephemeral (only available in iOS 14+)

Swift

let permissionNative: OSNotificationPermission = OneSignal.Notifications.permissionNative.rawValue

Push notification events

addClickListener() Push

Runs when a user clicks a push notification that opens the app. The app is already launched by the time this fires — do not relaunch or duplicate navigation. Use removeClickListener() or removeEventListener() to stop listening.

In Flutter Debug mode, force-closing the app prevents click listeners from registering. Use a release build (flutter run --release) or set the Xcode scheme to Release.

Kotlin

val clickListener = object : INotificationClickListener {
  override fun onClick(event: INotificationClickEvent) {
    Log.d("OneSignal", "Notification clicked: ${event.notification.title}")
  }
}
OneSignal.Notifications.addClickListener(clickListener)

addForegroundLifecycleListener() Push

Intercepts notifications received while the app is in the foreground. By default, OneSignal displays them automatically. Call event.preventDefault() to suppress or delay display, then event.notification.display() to show it manually.

This runs after Notification Service Extensions, which modify the payload before display.

Use removeForegroundLifecycleListener() or removeEventListener() to stop listening.

Kotlin

val lifecycleListener = object : INotificationLifecycleListener {
  override fun onWillDisplay(event: INotificationWillDisplayEvent) {
    Log.d("OneSignal", "Foreground notification: ${event.notification.title}")
    // Uncomment to prevent the notification from being displayed while in the foreground
    // event.preventDefault()
  }
}
OneSignal.Notifications.addForegroundLifecycleListener(lifecycleListener)

clearAllNotifications()

Removes all OneSignal notifications from the Notification Shade. Use instead of Android’s android.app.NotificationManager.cancel. Otherwise, the notifications will be restored when your app is restarted.

Kotlin

OneSignal.Notifications.clearAllNotifications()

removeNotification(), removeGroupedNotifications() Android

Cancel a single notification by its Android notification ID, or a group by its group key. Use these instead of android.app.NotificationManager.cancel — otherwise notifications will be restored when the app restarts.

Kotlin

OneSignal.Notifications.removeNotification(id)
OneSignal.Notifications.removeGroupedNotifications("GROUP_KEY")

---

In-App Messages

In-app messages do not require any code; however, the SDK enables you to customize when messages are presented and handle lifecycle events.

addTrigger(), addTriggers()

Decide when to display an In-App Message based on a single or multiple triggers. See Triggers for more information.

Triggers are not persisted to the backend. They only exist on the local device and apply to the current user.

Kotlin

OneSignal.InAppMessages.addTrigger("KEY", "VALUE")

OneSignal.InAppMessages.addTriggers(mapOf("KEY_01" to "VALUE_01", "KEY_02" to "VALUE_02"))

removeTrigger(), removeTriggers(), clearTriggers()

Remove a single, multiple, or all triggers with the provided key from the current user.

Kotlin

OneSignal.InAppMessages.removeTrigger("KEY")

OneSignal.InAppMessages.removeTriggers(setOf("KEY_01", "KEY_02"))

OneSignal.InAppMessages.clearTriggers()

paused

Prevent In-app messages from being displayed to the user. When set to true, no in-app messages will be presented. When set to false, any messages the user qualifies for will be presented to them at the appropriate time.

Kotlin

OneSignal.InAppMessages.paused = true

addLifecycleListener()

Respond to or track In-App Messages being displayed and dismissed.

Kotlin

val lifecycleListener = object : IInAppMessageLifecycleListener {
  override fun onWillDisplay(event: IInAppMessageWillDisplayEvent) {
    print(event.message.messageId)
  }

  override fun onDidDisplay(event: IInAppMessageDidDisplayEvent) {
    print(event.message.messageId)
  }

  override fun onWillDismiss(event: IInAppMessageWillDismissEvent) {
    print(event.message.messageId)
  }

  override fun onDidDismiss(event: IInAppMessageDidDismissEvent) {
    print(event.message.messageId)
  }
}
OneSignal.InAppMessages.addLifecycleListener(lifecycleListener)
OneSignal.InAppMessages.removeLifecycleListener(lifecycleListener)

addClickListener() In-App

Respond to in-app message click events. The event contains the following click action metadata:

• actionId: A custom identifier you set on the element.
• urlTarget: An enum specifying how the launch URL for the message will be presented.
• url: The launch URL for the action, if any.
• closingMessage: A boolean value indicating if the action resulted in the message being closed.

Kotlin

val clickListener = object : IInAppMessageClickListener {
  override fun onClick(event: IInAppMessageClickEvent) {
    print(event.result.actionId)
  }
}
OneSignal.InAppMessages.addClickListener(clickListener)

---

Live Activity

Applications should allow users to opt-in to Live Activities. For example, your app gives the user the option to start the Live Activity within your US using a button or presenting an IAM. You may start and update a Live Activity via any method without an explicit prompt, unlike Notification Permission or Location Permission. Live Activities appear with the iOS Provisional Authorization UI. Live Activities must be started when your application is in the foreground. We recommend reading Apple’s developer guidelines to learn more about Live Activities.

setup()

Allows OneSignal to manage the lifecycle of a LiveActivity on behalf of the application. This includes listening for both pushToStart token updates and pushToUpdate token updates.

Swift

//... your app's code
OneSignal.LiveActivities.setup(MyWidgetAttributes.self);

setupDefault()

Allows cross platform SDK’s to manage the lifecycle of a LiveActivity by eliminating the need for a customer app to define and manage their own ActivityAttributes. See Cross-platform setup for further details.

C#

using OneSignalSDK;

//Push To Start
OneSignal.LiveActivities.SetupDefault();

//Launching the Live Activity from within the app (not needed for push to start)
string activityId = "my_activity_id";

OneSignal.LiveActivities.StartDefault(
  activityId,
  new Dictionary<string, object>() {
      { "title", "Welcome!" }
  },
  new Dictionary<string, object>() {
      { "message", new Dictionary<string, object>() {
          { "en", "Hello World!"}
      }},
  });

enter()

Entering a Live Activity associates an activityId with a Live Activity Temporary Push Token on our server. Specify this identifier when using the Update Live Activities REST API to update one or multiple Live Activities simultaneously.

Swift

// ... your app's code
let activity = try Activity<MyWidgetAttributes>.request(
  attributes: attributes,
  contentState: contentState,
  pushType: .token)
Task {
  for await data in activity.pushTokenUpdates {
      let token = data.map {String(format: "%02x", $0)}.joined()
      // ... required code for entering a live activity
      // Activity ID cannot contain "/" characters
      OneSignal.LiveActivities.enter("ACTIVITY_ID", withToken: token)
  }
}

exit()

Exiting a Live activity deletes the association between an Activity Identifier with the Live Activity push token on our server.

Swift

OneSignal.LiveActivities.exit("ACTIVITY_ID")

setPushToStartToken()

Optional “low-level” approach to push to start live activities. Offers fine-grained control over the LiveActivity start and update tokens without altering the ActivityAttribute structure. Additional details available here

Swift

if #available(iOS 17.2, *) {
  // Setup an async task to monitor and send pushToStartToken updates to OneSignalSDK.
  Task {
      for try await data in Activity<MyWidgetAttributes>.pushToStartTokenUpdates {
          let token = data.map {String(format: "%02x", $0)}.joined()
          OneSignal.LiveActivities.setPushToStartToken(MyWidgetAttributes.self, withToken: token)
      }
  }
  // Setup an async task to monitor for an activity to be started, for each started activity we
  // can then set up an async task to monitor and send updateToken updates to OneSignalSDK.
  Task {
      for await activity in Activity<MyWidgetAttributes>.activityUpdates {
        Task {
            for await pushToken in activity.pushTokenUpdates {
                let token = pushToken.map {String(format: "%02x", $0)}.joined()
                OneSignal.LiveActivities.enter("my-activity-id", withToken: token)
            }
        }
      }
  }
}

removePushToStartToken()

Called per-activity-type whenever that activity type should no longer be registered against the current subscription

Swift

OneSignal.LiveActivities.removePushToStartToken(MyWidgetAttributes.self)

---

Outcomes

Track actions taken by users and attribute them to messages. See Outcomes for more details.

addOutcome(), addUniqueOutcome(), addOutcomeWithValue()

• addOutcome(name) — Add an outcome captured against the current session.
• addUniqueOutcome(name) — Add a unique outcome (counted once per session).
• addOutcomeWithValue(name, value) — Add an outcome with a numeric value.

Kotlin

OneSignal.Session.addOutcome("OUTCOME_NAME")
OneSignal.Session.addUniqueOutcome("OUTCOME_NAME")
OneSignal.Session.addOutcomeWithValue("OUTCOME_NAME", 3.14)

---

FAQ

What is the difference between onesignal_id and the Subscription ID?

The onesignal_id is a user-level identifier that represents a person across all their devices and channels. The Subscription ID (User.pushSubscription.id) is a device-level identifier for a single push channel. One user can have multiple Subscriptions.

Do I need to call login() every time the app starts?

Yes. Call login(external_id) on every app launch once you know the user’s identifier (after sign-in or session restore). The SDK handles deduplication — if the user is already logged in with that ID, the call is effectively a no-op.

What happens to anonymous data when I call login()?

If the external_id already exists, anonymous data (tags, session data, email/SMS Subscriptions) collected before login is discarded. If the external_id is new, the anonymous data is retained and associated with the newly created user.

Why does getOnesignalId() return null?

The OneSignal ID is not available until the SDK finishes initializing. If you call getOnesignalId() too early (for example, immediately after initialize()), it may return null. Use User State addObserver() to reliably detect when the ID becomes available.