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We are always happy to help with the implementation of the SDK. If you have any questions, please reach out.

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The React Native Expo SDK

The React Native Expo SDK is published in GitHub at https://github.com/prelude-so/react-native-sdk .

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Using the Expo React Native SDK

The Expo React Native SDK allows you to capture certain device signals (both in Android and iOS) that will be reported back to Prelude and perform silent verification of mobile devices. It is provided as an Expo module that you can integrate into your React Native Expo Application. The Android minSdkVersion value in the SDK is set to 26 (Android 8.0). If your application has a lower value you may need to update it.

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Usage

The SDK is available in npmjs. You can install the SDK dependency directly from npm: 
npm install @prelude.so/react-native-sdk
You will need to have the Prelude SDK key that you generate in the Prelude dashboard for your account. Important: When you generate the SDK key in the Prelude dashboard, you will be able to copy it, and you should store it somewhere secure, as the dashboard will not allow you to display the same key again.

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Gathering Device Signals

Note: Starting with v0.3.0 of the SDK, we have removed the status event and made the dispatchSignals function return a promise that resolves to the dispatch identifier, simplifying its usage. To collect the device signals in your application, you can use code like this: 
...
// Import the SDK types
import * as PreludeReactNativeSdk from '@prelude.so/react-native-sdk';
...

...
// Submit the signals in any of your app event handlers (here is a button example)
<Button title={`Dispatch Signals`} onPress={ async () =>
  {
    try {
        const dispatchId = await PreludeReactNativeSdk.dispatchSignals({
          sdk_key: "YOUR_SDK_KEY", // Replace with your Prelude SDK key
        });

        // Handle the dispatch ID as needed,
        // e.g., store it or continue with verification here
        alert(`Dispatch ID: ${dispatchId}`);
    } catch (error) {
        alert(`Signals dispatch error: ${error.message}`);
    }
  }}
/>
Then run the Expo application normally (in your application’s directory): 
npx expo run:ios
or 
npx expo run:android
Once you get the dispatch identifier through the event, you can report it back to your own API to be forwarded in later network calls, for example, when starting the onboarding verification process for a user. There are some arguments that you can use to fine-tune the behavior of the dispatchSignals function for your use case: 
...
await PreludeReactNativeSdk.dispatchSignals({
  sdk_key: "YOUR_SDK_KEY",
  timeout_milliseconds: 5000, // Optional timeout in milliseconds for each network request (default is 5000 ms)
  max_retries: 3,             // Optional maximum number of automatic retries with exponential backoff for each network request (default is 3)
});
...

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Silent Verification

The Silent Verification feature allows you to verify a phone number without requiring the user to manually enter a verification code. It is available for certain carriers and requires a server-side service to handle the verification process. For this verification method to work properly, you must collect the device signals mentioned before and report the dispatch identifier to your back-end (usually in your APIs verification endpoint). Please refer to the Silent Verification documentation for more information on how to implement this feature.

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Uploading your app to the App Store

Depending on the mechanism that you use to upload your app to the App Store, you may find errors related to the PreludeCore.xcframework file. If you encounter this error, try uploading the app again without the PreludeCore.xcframework with the flag --use-old-altool: 
xcrun altool --upload-app --type ios --file "path/to/your/app.ipa" --apiKey "YourAPIKey" --apiIssuer "YourIssuerID" --use-old-altool
If you use Transporter it will not allow you to use the --use-old-altool flag. You will need to use the xcrun command instead.