The Rownd SDK for Android provides authentication, account and user profile management, deep linking, encryption and more for native Android applications.

Using the Rownd platform, you can easily bring the same authentication that’s on your website to your mobile apps. Or if you only authenticate users on your mobile apps, you can streamline the authentication process using Rownd’s passwordless sign-in links, enabling you to seamlessly authenticate users from an app link sent to their email or phone number.

Once a user is authenticated, you can retrieve and update their profile information on the fly using native APIs. Leverage Rownd’s pre-built mobile app components to give users profile management tools. Additionally, you can manage encryption of data on-device before sending it back to Rownd or your own backend.

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Installation

In Android Studio, open your app’s module-level build.gradle file and add the following dependency:

implementation 'io.rownd:android:2.4.1'

After adding, run a Gradle sync and the Rownd SDK/API should be available within your IDE.

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ProGuard config

If you’re using ProGuard to shrink, obfuscate, and/or optimize your app (and you should!), you’ll need to add the following rules to your proguard-rules.pro file.

-if @kotlinx.serialization.Serializable class **
-keepclassmembers class <1> {
   static <1>$Companion Companion;
}

# Keep `serializer()` on companion objects (both default and named) of serializable classes.
-if @kotlinx.serialization.Serializable class ** {
   static **$* *;
}
-keepclassmembers class <2>$<3> {
   kotlinx.serialization.KSerializer serializer(...);
}

# Keep `INSTANCE.serializer()` of serializable objects.
-if @kotlinx.serialization.Serializable class ** {
   public static ** INSTANCE;
}
-keepclassmembers class <1> {
   public static <1> INSTANCE;
   kotlinx.serialization.KSerializer serializer(...);
}

# @Serializable and @Polymorphic are used at runtime for polymorphic serialization.
-keepattributes RuntimeVisibleAnnotations,AnnotationDefault,Annotation,InnerClasses

# Suppress warnings about missing AWT classes (which aren't used in Android)
-dontwarn java.awt.*

# libsodium uses jna
-keep class com.sun.jna.* { *; }
-keepclassmembers class * extends com.sun.jna.* { public *; }

# ViewModel names are used at runtime
-keep public class * extends androidx.lifecycle.ViewModel {*;}

​
Usage

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Initializing the Rownd SDK

The Rownd SDK needs access to your application’s and current activity’s context in order to properly manage state, display UI components, and so on.

The most straightforward way of doing this is to subclass the Android Application class and pass the app’s primary context.

To initialize Rownd, call the configure method like this:

Rownd.configure(application, "REPLACE_WITH_YOUR_APP_KEY")

Here’s an example of what that might look like in the initial Application class:

class MyApplication : Application() {
    override fun onCreate() {
        super.onCreate()
        Rownd.configure(this, "REPLACE_WITH_YOUR_APP_KEY")
    }
}

After initialization, your app should typically call Rownd.requestSignIn() at some point, if the user is not already authenticated. This will display the Rownd interface for authenticating the user. Once they complete the sign-in process, an access token and the user’s profile information will be available to your app.

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Handling authentication

Rownd leverages an observable architecture to expose data to your app using StateFlow. This means that as the Rownd state changes, an app can dynamically update without complicated logic. For example, a view can display different information based on the user’s authentication status.

You can use this StateFlow in both older-style XML layouts as well as Android Jetpack’s newer Composable views.

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Using state in XML layout

// my_layout.xml

<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:tools="http://schemas.android.com/tools"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:android="http://schemas.android.com/apk/res/android">

    <data>
        <import type="android.view.View" />
        <variable
            name="rownd"
            type="io.rownd.android.Rownd" />
    </data>

    <androidx.constraintlayout.widget.ConstraintLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context=".MainActivity">

        <TextView
            android:id="@+id/textView"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@{@string/hello_rownd_state_user_data(rownd.state.user.data.first_name)}"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent"
            app:layout_constraintVertical_bias="0.19999999" />

    </androidx.constraintlayout.widget.ConstraintLayout>
</layout>

// my_activity.kt
class MyActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        val binding: ActivityMainBinding =
            DataBindingUtil.setContentView(this, R.layout.activity_main)

        binding.lifecycleOwner = this

        binding.rownd = Rownd
    }
}

​
Using state in a Composable

// some_activity_or_component.kt

class MyActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        setContent {
            val state = Rownd.state.collectAsState()
            val signInButtonText = if (state.value.auth.isAuthenticated) "Sign out" else "Sign in"
            Button(
                onClick = {
                    if (state.value.auth.isAuthenticated) Rownd.signOut()
                    else Rownd.requestSignIn()
                }
            ) {
                Text(signInButtonText)
            }
        }
    }
}

Once you subscribe to the Rownd state via Rownd.state.collectAsState(), you can use the various parts of the state tree as needed.

Access the state like this:

val rowndState = Rownd.state.collectAsState()

val isAuthenticated = rowndState.value.auth.isAuthenticated

The following classes/properties are available:

​
.auth

data class AuthState(
    val accessToken: String?, // Current, valid access token for the user (valid for one hour)
    val isVerifiedUser: Boolean, // Whether the current user has verified at least one identifier (e.g., email)
    val isAuthenticated: Boolean // Whether the current user is signed in
)

​
.user

data class User(
    val id: String?,  // The user's ID as known to Rownd
    val data: Map<String, @Serializable(with = AnyValueSerializer::class) Any?> = HashMap<String, Any?>(),
    val redacted: PersistentList<String> // A list of any profile fields that a user has restricted your app from accessing
)

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Customizing the UI

While most customizations are handled via the Rownd dashboard, there are a few things that have to be customized directly in the SDK.

The RowndCustomizations class exists to facilitate these customizations. It provides the following properties that may be subclassed or overridden.

  • sheetBackgroundColor: Color? (default: null) - Allows setting a single color for Rownd-provided bottom sheet interfaces regardless of system theme. Use this or dynamicSheetBackgroundColor, but not both.
  • dynamicSheetBackgroundColor: Color (default: light: #ffffff, dark: #1c1c1e; requires subclassing) - Allows changing the background color underlaying the bottom sheet that appears when signing in, managing the user account, transferring encryption keys, etc. based on the system color scheme.
  • sheetCornerBorderRadius: Dp (default: 25.dp) - Modifies the curvature radius of the bottom sheet’s top corners.
  • loadingAnimation: Int (default: null) - Replace Rownd’s use of the system default loading spinner (i.e., ProgressBar) with a custom animation. Any animation resource compatible with Lottie should work, but will be scaled to fit a 1:1 aspect ratio (usually with a frame width/height of 100) This should be a value like R.raw.my_animation

To apply customizations, we recommend subclassing the RowndCustomizations class. Here’s an example:

class AppCustomizations(app: Application) : RowndCustomizations() {
    private var app: Application

    init {
        this.app = app
    }

    override val dynamicSheetBackgroundColor: Color
    get() {
            val uiMode = app.resources.configuration.uiMode and Configuration.UI_MODE_NIGHT_MASK
            return if (uiMode == Configuration.UI_MODE_NIGHT_YES) {
                Color(0xff123456)
            } else {
                Color(0xfffedcba)

            }
        }

    override var sheetCornerBorderRadius: Dp = 25.dp

    override var loadingAnimation: Int? = R.raw.loading
}

// MyApplication.kt
import android.app.Application
import android.content.res.Configuration
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.unit.Dp
import androidx.compose.ui.unit.dp
import io.rownd.android.Rownd
import io.rownd.android.models.RowndCustomizations

class MyApplication: Application() {

    override fun onCreate() {
        super.onCreate()

        Rownd.configure(this, "b60bc454-c45f-47a2-8f8a-12b2062f5a77")
        Rownd.config.customizations = AppCustomizations(this)

    }
}

​
API reference

In addition to the StateFlow APIs, Rownd provides imperative APIs that you can call to request sign in, get and retrieve user profile information, retrieve a current access token, or encrypt user data with the user’s local key.

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Rownd.requestSignIn(): Unit

Opens the Rownd sign-in dialog for authentication.

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Rownd.requestSignIn(with = RowndSignInHint)

Initiates a sign-in using the method specified by the with argument, bypassing the authentication method selector. For example, this could be used to steer a new user toward a specific sign-in method.

Supported options:

  • RowndSignInHint.Google - Prompt user to sign in with their Google account
  • RowndSignInHint.OneTap - Prompt user to sign into their account with Google One Tap
  • RowndSignInHint.Passkey - Prompt user to sign in with a passkey if they’ve previously set one up
  • RowndSignInHint.Guest - Sign in the user anonymously as a guest.

Example:

Rownd.requestSignIn(with = RowndSignInHint.Google)

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Rownd.requestSignIn(RowndSignInOpts(…)): Unit

Opens the Rownd sign-in dialog for authentication, as before, but allows passing additional context options as shown below.

  • intent: RowndSignInIntent - This option applies only when you have opted to split the sign-up/sign-in flow via the Rownd dashboard. Valid values are .SignIn or .SignUp. If you don’t set this value, the user will be presented with the unified sign-in/sign-up flow. Please reach out to support@rownd.io to enable.

  • postSignInRedirect: String (Not recommended) - If you’ve followed the steps to enable Android App Links, the redirect will be handled automatically. When the user completes the authentication challenge via email or SMS, they’ll be redirected to the URL set for postSignInRedirect. If this is an Android App Link, it will redirect the user back to your app.

Example:

Rownd.requestSignIn(RowndSignInOpts(
    intent = RowndSignInIntent.SignUp
))

The following user profile APIs technically accept Any as the value of a field. However, that value must be serializable using Kotlin’s Serialization library. If the value is not serializable out of the box, you’ll need to provide your own serializer implementation as described in the Kotlin documentation.

​
suspend Rownd.getAccessToken(): String?

Assuming a user is signed-in, returns a valid access token, refreshing the current one if needed. If an access token cannot be returned due to a temporary condition (e.g., inaccessible network), this function will throw. If an access token cannot be returned because the refresh token is invalid, null will be returned and the Rownd state will sign out the user.

Example:

    val accessToken = Rownd.getAccessToken()

​
suspend Rownd.getAccessToken(token: String): String?

When possible, exchanges a non-Rownd access token for a Rownd access token. This is primarily used in scenarios where an app is migrating from some other authentication mechanism to Rownd. Using Rownd integrations, the system will accept a third-party token. If it successfully validates, Rownd will sign-in the user and return a fresh Rownd access token to the caller.

This API returns null if the token could not be validated and exchanged. If that occurs, it’s likely that the user should sign-in normally via Rownd.requestSignIn().

NOTE: This API is typically used once. After a Rownd token is available, other tokens should be discarded.

Example:

    // Assume `oldToken` was retrieved from some prior authenticator.
    val accessToken = Rownd.getAccessToken(oldToken)

    if (accessToken != null) {
        // Navigate to the UI that a user should typically see
    } else {
        Rownd.requestSignIn()
    }

​
Rownd.user.get(): Map<String, Any?>

Returns the entire user profile as a Map

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Rownd.user.get<T>(field: String): T?

Returns the value of a specific field in the user’s data Map. "id" is a special case that will return the user’s ID, even though it’s technically not in the Map itself.

Your application code is responsible for knowing which type the value should cast to. If the cast fails or the entry doesn’t exist, a null value will be returned.

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Rownd.user.set(data: Map<String, Any?>): Void

Replaces the user’s data with that contained in the Map. This may overwrite existing values, but must match the schema you defined within your Rownd application dashboard. Any fields that are flagged as encrypted will be encrypted on-device prior to storing in Rownd’s platform.

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Rownd.user.set(field: String, value: Any): Void

Sets a specific user profile field to the provided value, overwriting if a value already exists. If the field is flagged as encrypted, it will be encrypted on-device prior to storing in Rownd’s platform.

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Data encryption

As indicated previously, Rownd can automatically assist you in protecting sensitive user data by encrypting it on-device with a user’s unique encryption key prior to saving it in Rownd’s own platform storage.

When you configure your app within the Rownd platform, you can indicate that it supports on-device encryption. When this flag is set, Rownd will automatically generate a cryptographically secure, unrecoverable encryption key on the user’s device after they sign in. The key is stored using Android’s native KeyStore mechanisms and all encryption is handled on the device. The key is never transmitted to Rownd’s servers and the Rownd SDK does not provide any APIs to for your code to programmatically retrieve the encryption key.

Only fields that you designate encrypted are encrypted on-device prior to storing within Rownd. Some identifying fields like email and phone number do not support on-device encryption at this time, since they are frequently used for indexing purposes.

Of course, all data within the Rownd platform is encrypted at rest on disk and in transit, but this does not afford the same privacy guarantees as data encrypted on a user’s local device. For especially sensitive data, we recommend enabling field-level encryption.

Data encrypted on-device will not be accessible by you, the app developer, outside of the context of your app. In other words, your app can use encrypted data in its plaintext (decrypted) form while the user is signed in, but you won’t be able to retrieve that data from the Rownd servers in a decrypted form. For data that you choose to encrypt, you should never transmit the plain text value across a network.

In some cases, you may want to encrypt data on-device that you’ll send to your own servers for storage. Rownd provides convenience methods to encrypt and decrypt that data with the same user-owned key.

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Rownd.user.encrypt(plaintext: String): String

Encrypts the provided String data using the user’s symmetric encryption key and returns the ciphertext as a string. You can encrypt anything that can be represented as a string (e.g., Int, Dictionary, Array, etc), but it’s currently up to you to get it into a string format first.

If the encryption fails, an EncryptionException will be thrown with a message explaining the failure.

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Rownd.user.decrypt(ciphertext: String): String

Attempts to decrypt the provided String data, returning the plaintext as a string. If the data originated as some other type (e.g., Map), you’ll need to decode the data back into its original type.

If the decryption fails, an EncryptionException will be thrown with a message explaining the failure.

Encryption is only possible once a user has authenticated. Rownd supports multiple levels of authentication (e.g., guest, unverified, and verified), but the lowest level of authentication must be achieved prior to encrypting or decrypting data. If you need to explicitly check whether encryption is possible at a specific point in time, call Rownd.user.isEncryptionPossible(): Boolean prior to calling encrypt() or decrypt().

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Events

The Rownd SDK emits lifecycle events that you can listen to within your app. These events are primarily useful for detecting more granular aspects of a user’s session (e.g., starting to sign in, completing sign-in, updated profile, etc.).

To listen to events, pass a function or closure that accepts a RowndEvent object to Rownd.addEventListener(). It might look something like this:

class MyApp: Application() {

    override fun onCreate() {
        super.onCreate()

        Rownd.addEventListener {
            when (it.event) {
                RowndEventType.SignInStarted -> {
                    // Do stuff
                }
                RowndEventType.SignInCompleted -> {
                    it.data?.get("user_type")?.let { it1 -> Log.d("App", it1.toString()) }
                }

                else -> {
                    // no-op
                }
            }
        }
    }
}

This registers the event listener with the Rownd SDK. You can also unregister the listener by calling Rownd.removeEventListener() with the same function or closure if you assign it to a variable.

Once the event handler is registered, it will receive events as they occur. The RowndEvent object contains the event type and any associated data. The event types are defined in the RowndEventType enum.

NOTE: You’ll need implementation "org.jetbrains.kotlinx:kotlinx-serialization-json" listed as a dependency in your build.gradle file in order to access the data JsonObject in the RowndEvent object.

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List of events

Here’s a list of events that the Rownd SDK emits and the corresponding data that should be present in the event data dictionary. Remember to write your code defensively, as the data dictionary may be missing keys in some cases.

EventTypePayload
User started signing inRowndEventType.SignInStarted
{
	method: "google" | "apple" | "phone" | "email" | "passkey" | etc
}
User signed in successfullyRowndEventType.SignInCompleted
{
	method: "google" | "apple" | "phone" | "email" | "passkey" | etc,
	user_type: "new_user" | "existing_user"
    app_variant_user_type: 'new_user' | 'existing_user' | optional
}
User sign in failedRowndEventType.SignInFailed
{
	reason: string
}
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