Setting a User ID

Send your internal user ID to Singular to enable cross-device tracking and user-level data reporting.

User ID Requirements

Privacy and Best Practices

Follow these guidelines when implementing user ID tracking to ensure privacy compliance and proper cross-device measurement.

• No PII: The User ID should not expose Personally Identifiable Information (PII) such as email addresses, usernames, or phone numbers. Use a hashed value unique to your first-party data.
• Consistency Across Platforms: The User ID value must be the same internal identifier you capture across all platforms (Web/Mobile/PC/Console/Offline) for accurate cross-device measurement.
• First-Party Data: Singular includes the User ID in user-level exports, ETL, and Internal BI postbacks (if configured). The User ID is first-party data and is not shared with third parties.
• Persistence: The User ID persists until explicitly unset using unsetCustomUserId() or until the app is uninstalled. Closing or restarting the app does not clear the User ID.

Implementation Overview

When to Set the User ID

Use Singular.setCustomUserId() to set the user identifier and Singular.unsetCustomUserId() to clear it during logout.

If you already know the user ID when the app opens, configure it using withCustomUserId() before initializing the Singular SDK. This ensures Singular receives the User ID from the first session. However, the User ID is typically unavailable until the user registers or logs in, in which case call setCustomUserId() after the registration or authentication flow completes.

SDK Methods

Set Custom User ID

Send your internal user ID to Singular for cross-device tracking and user-level reporting.

// TurboModule direct API (React Native 0.76+ New Architecture)
import NativeSingular from 'singular-react-native/js/NativeSingular';

// Set the user ID after login or registration
NativeSingular.setCustomUserId('user_123456');

import { Singular } from 'singular-react-native';

// Set the user ID after login or registration
Singular.setCustomUserId('user_123456');

Method Signature:

static setCustomUserId(customUserId: string): void

Example: Set User ID After Login

Call setCustomUserId() immediately after the user successfully completes authentication to ensure all subsequent events are associated with their user ID.

// TurboModule direct API (React Native 0.76+ New Architecture)
import NativeSingular from 'singular-react-native/js/NativeSingular';

async function handleUserLogin(email, password) {
  try {
    // Your authentication logic
    const response = await authenticateUser(email, password);

    if (response.success) {
      // Set the user ID in Singular after successful login
      NativeSingular.setCustomUserId(response.userId);

      console.log('User ID set:', response.userId);

      // Navigate to home screen
      navigateToHome();
    }
  } catch (error) {
    console.error('Login failed:', error);
  }
}

import { Singular } from 'singular-react-native';

async function handleUserLogin(email, password) {
  try {
    // Your authentication logic
    const response = await authenticateUser(email, password);

    if (response.success) {
      // Set the user ID in Singular after successful login
      Singular.setCustomUserId(response.userId);

      console.log('User ID set:', response.userId);

      // Navigate to home screen
      navigateToHome();
    }
  } catch (error) {
    console.error('Login failed:', error);
  }
}

Unset Custom User ID

Clear the user ID when a user logs out to ensure accurate session tracking for multi-user devices.

// TurboModule direct API (React Native 0.76+ New Architecture)
import NativeSingular from 'singular-react-native/js/NativeSingular';

// Unset the user ID on logout
NativeSingular.unsetCustomUserId();

import { Singular } from 'singular-react-native';

// Unset the user ID on logout
Singular.unsetCustomUserId();

Method Signature:

static unsetCustomUserId(): void

Example: Unset User ID on Logout

Call unsetCustomUserId() during the logout flow to clear the user ID and prevent incorrect attribution of subsequent events.

// TurboModule direct API (React Native 0.76+ New Architecture)
import NativeSingular from 'singular-react-native/js/NativeSingular';

async function handleUserLogout() {
  try {
    // Clear app data and user session
    await clearUserSession();

    // Unset the user ID in Singular
    NativeSingular.unsetCustomUserId();

    console.log('User ID cleared');

    // Navigate to login screen
    navigateToLogin();
  } catch (error) {
    console.error('Logout failed:', error);
  }
}

import { Singular } from 'singular-react-native';

async function handleUserLogout() {
  try {
    // Clear app data and user session
    await clearUserSession();

    // Unset the user ID in Singular
    Singular.unsetCustomUserId();

    console.log('User ID cleared');

    // Navigate to login screen
    navigateToLogin();
  } catch (error) {
    console.error('Logout failed:', error);
  }
}

Set User ID During Initialization

If the user ID is available when the app launches (e.g., user is already logged in), configure it during SDK initialization using withCustomUserId(). This ensures the first session includes the user ID.

// TurboModule direct API (React Native 0.76+ New Architecture)
import React, { useEffect } from 'react';
import NativeSingular from 'singular-react-native/js/NativeSingular';
import AsyncStorage from '@react-native-async-storage/async-storage';

export default function App() {
  useEffect(() = {
    initializeSingular();
  }, []);

  async function initializeSingular() {
    // Check if user is already logged in
    const userId = await AsyncStorage.getItem('user_id');

    // Create configuration object
    const config: SingularConfig = {
      apikey: 'YOUR_SDK_KEY',
      secret: 'YOUR_SDK_SECRET',
      ...(userId ? { customUserId: userId } : {}),
    };

    // Initialize SDK
    NativeSingular.init(config);
  }

  return (
    // Your app components
    null
  );
}

import React, { useEffect } from 'react';
import { Singular, SingularConfig } from 'singular-react-native';
import AsyncStorage from '@react-native-async-storage/async-storage';

export default function App() {
  useEffect(() => {
    initializeSingular();
  }, []);

  async function initializeSingular() {
    // Check if user is already logged in
    const userId = await AsyncStorage.getItem('user_id');

    // Create configuration
    const config = new SingularConfig(
      'YOUR_SDK_KEY',
      'YOUR_SDK_SECRET'
    );

    // If user ID exists, set it during initialization
    if (userId) {
      config.withCustomUserId(userId);
    }

    // Initialize SDK
    Singular.init(config);
  }

  return (
    // Your app components
  );
}

Configuration Method Signature:

withCustomUserId(customUserId: string): SingularConfig