Mobile attribution

This guide walks through how to set up mobile app referral attribution.

This guide explains how to add referral tracking capabilities to your existing attribution links without creating new ones. In this guide, we’ll use Branch.io as an example.

Overview

The referral flow works as follows:

  • Existing user shares their unique referral link

  • New user clicks the link and is directed to app store

  • New user installs and opens the app

  • App receives referral data and attributes the installation

  • Backend records the referral during signup

Basic Concept

Instead of creating new links for each referrer, you'll append referral data to your existing Branch.io app install link:

Original: https://yourbrand.app.link/abc123
With Referral: https://yourbrand.app.link/abc123?referral_ucc=A1B2C

Data Persists Through Installation

When a user clicks the referral link, Branch.io stores the referral data (including the referral_ucc) in their servers and associates it with the user's device fingerprint. This allows the data to persist through:

  • App Store redirect

  • App download

  • First app launch

Data Flow Sequence

https://yourbrand.app.link/abc123?referral_ucc=A1B2C
↓
Branch.io captures and stores:
- referral_ucc: A1B2C
- Device fingerprint
- Click timestamp

App Installation

User installs app from store
↓
Branch SDK initializes on first launch
↓
Branch matches device to stored click data
↓
Delivers referral data to app

Accessing Referral Data in Your App

iOS Implementation

import Branch

class AppDelegate: UIResponder, UIApplicationDelegate {
func application(_ application: UIApplication,
didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
Branch.getInstance().initSession(launchOptions: launchOptions) { (params, error) in
// Check if the user came from a Branch link
if let clickedBranchLink = params?["+clicked_branch_link"] as? Bool,
clickedBranchLink {
// Extract referral code
if let referralCode = params?["referral_ucc"] as? String {
print("Referral Code: \(referralCode)")
// Store for use during signup
UserDefaults.standard.set(referralCode,

Android Implementation

class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
Branch.getAutoInstance(this).initSession({ branchUniversalObject, linkProperties, error ->
if (error == null) {
// Check if user came from Branch link
if (linkProperties?.has("+clicked_branch_link") == true) {
// Get referral code
val referralCode = linkProperties.get("referral_ucc")
referralCode?.let {
Log.d("Branch", "Referral Code: $it")
// Store for signup
getSharedPreferences("app_prefs", Context.MODE_PRIVATE)
.edit()

React Native Implementation

import branch from 'react-native-branch';

function DeepLinkHandler() {
useEffect(() => {
// Handle deep link when app is already running
const subscription = branch.subscribe({
onNewIntent: ({ error, params, uri }) => {
if (error) {
console.error('Branch link error:', error);
return;
}

if (params['+clicked_branch_link']) {
handleDeepLink(params);
}
}
});

return () => subscription();
}, []);

const handleDeepLink = async (params) => {
const referralCode = params.referral_ucc;
if (referralCode) {
await AsyncStorage.setItem('pending_referral_code', referralCode);

Using the Referral Data During Signup

When the user completes signup, retrieve the stored referral code and include it in your signup API call:

iOS Implementation

// iOS Example
class SignupViewController: UIViewController {
func completeSignup(email: String, password: String) {
// Get stored referral code
let referralCode = UserDefaults.standard.string(forKey: "pending_referral_code")
// Include in signup API call
let signupData = [
"email": email,
"password": password,
"referral_code": referralCode
]
api.signup(signupData) { result in
if result.success {
// Clear stored referral data after successful signup
UserDefaults.standard.removeObject(forKey: "pending_referral_code")
}
}
}
}

Android Implementation

// Android Example
class SignupActivity : AppCompatActivity() {
private fun completeSignup(email: String, password: String) {
val prefs = getSharedPreferences("app_prefs", Context.MODE_PRIVATE)
val referralCode = prefs.getString("pending_referral_code", null)
val signupData = HashMap<String, String>().apply {
put("email", email)
put("password", password)
referralCode?.let { put("referral_code", it) }
}
api.signup(signupData) { success ->
if (success) {
// Clear stored referral data
prefs.edit().remove("pending_referral_code").apply()
}
}
}
}

React Native Implementation

function SignupScreen({ navigation }) {
const [email, setEmail] = useState('');
const [password, setPassword] = useState('');

const handleSignup = async () => {
try {
const referralCode = await AsyncStorage.getItem('pending_referral_code');
const response = await api.signup({
email,
password,
referral_code: referralCode
});

if (response.success) {
await AsyncStorage.removeItem('pending_referral_code');
navigation.navigate('Home');
}
} catch (error) {
console.error('Signup error:', error);
}
};

return (
// Your signup form JSX
);


On This Page
Mobile attributionOverviewBasic ConceptData Persists Through InstallationData Flow SequenceAccessing Referral Data in Your AppUsing the Referral Data During SignupLink ClickApp InstallationiOS ImplementationAndroid ImplementationReact Native ImplementationiOS ImplementationAndroid ImplementationReact Native Implementation