Get Started with SubscriberCheck on React Native

Get Started with React Native

This guide walks you through what is required on your React Native app in order to perform a SubscriberCheck using tru.ID's React Native SDK. However, if you wish to see the finished working example app, you can find it on our GitHub respository. It covers:

1. Before You Begin

To fully understand the functionality required to create a SubscriberCheck in this guide, you will need to carry out some initial steps, such as creating an account, a project, and retrieving your workspace credentials. You'll also need to have an understanding of the workflow for a SubscriberCheck to be successfully carried out.

The first step is to Setup Your Environment. This page walks you through what parts are required, such as installing the tru.ID CLI, creating a project, and if needed, running the demo development server.

The second step is to gain more of an understanding of how the SubscriberCheck works. The Integration Guide provides a step by step guide on the workflow of a SubscriberCheck, and which devices need to act at what points of the workflow.

2. Install tru.ID React Native SDK

The tru.ID React Native SDK on Android requires a minimum API level of 21 (Android 5), and a compile level needs to be API 30 (Android 11) or later.

The Flutter SDK on iOS requires a minimum iOS 12+.

In the project's Android directory, open the build.gradle file, add the tru.ID's Android SDK public repository within the buildscript and allprojects repository sections, similar to what's shown below:

buildscript {
repositories {
maven {
url ""
allprojects {
repositories {
maven {
url ""

Then in your terminal, within the project's root directory run the following command to install the React Native SDK as a dependency:

npm install @tru_id/tru-sdk-react-native

3. How to implement into my app?

Importing and Initializing the SDK

Before proceeding, be sure to sync your project for these new dependencies to be installed.

Initialize tru.ID SDK

import TruSdkReactNative from "@tru_id/tru-sdk-react-native";


The Reachability API is a feature that enables applications to check whether the SIM card within a user's device is on a network that tru.ID has connectivity to.

The React Native SDK has functionality built in to call the reachability, to call this you would need to run the following code:

const details = await TruSdkReactNative.isReachable();

If the mobile network operator is supported by tru.ID then a JSON object is returned similar to the example below:

"network_id": "23410",
"network_name": "O2 UK",
"country_code": "GB",
"products": [
"product_id": "SCK",
"product_name": "SubscriberCheck"

However, if it isn't supported, then an error is returned in JSON format.

Call your backend server to create SubscriberCheck

As described in the Integration guide step 1 is to create a SubscriberCheck. This step is a step where your mobile application needs to call your backend server with the mobile devices telephone number. Your backend server then makes a POST request to tru.ID's SubscriberCheck API. If successful, the SubscriberCheck API will return a response with the check_id and a unique check_url. Your backend server needs to return this check_url to the mobile device.

Open Check URL to process SubscriberCheck

Step 2 of the integration guide is to process the SubscriberCheck. This step is a step where the mobile application makes a GET request to the check_url provided in the previous step. The mobile device application then needs to follow all redirects, then on the last redirect, the JSON response will contain a code. This code will be used next.

await TruSdkReactNative.checkUrlWithResponseBody(url);

Call Backend server to complete SubscriberCheck

Step 3 of the integration guide is to complete the SubscriberCheck. This step is a step where the mobile application makes a POST request to your backend server with the check_id and the code. Your backend server then makes a PATCH request to /subscriber_check/v0.2/checks/{check_id} with the JSON body below to complete the SubscriberCheck process:

"op": "add",
"path": "/code",
"value": "{check_code}"

Within the response of this PATCH request, there will be a field no_sim_change, this is the field used to show if the SIM card has been changed recently, which could be an indication whether the owner of the SIM card may be a victim of SIM swap fraud. If the value is true, then proceed with the SubscriberCheck.

Finally, your backend server would need to return a success or failure response to your mobile application to allow the user of this application to proceed.

4. Setup the React Native example application

Clone and configure the React Native example application

Open a new terminal and ensure you are in the tru-id-phonecheck-example working directory. Run the following command to clone the React Native example into a app-example-react-native directory:

git clone

And navigate into the newly created app-example-react-native directory:

cd app-example-react-native

Install the application dependencies:

yarn install # or npm install

Create a copy of the .env.example file, naming the new file .env:

cp .env.example .env

And update the configuration value for BASE_URL in .env to point to the public ngrok URL of the Node.js example server. For example:


Install and run the React App on Android


Detailed information on running an application on a device can be found in the

React Native documentation


Ensure your Android device is connected to your computer via USB with developer mode and USB debugging enabled.

Run the following in the terminal:

yarn android # or npm run android

The terminal output will look similar to the following:

react-native run-android
info Running jetifier to migrate libraries to AndroidX. You can disable it using "--no-jetifier" flag.
Jetifier found 968 file(s) to forward-jetify. Using 8 workers...
info JS server already running.
info Installing the app...
<===----------> 27% EXECUTING [25s]
48 actionable tasks: 48 executed
info Connecting to the development server...
info Starting the app on "08231FDD4004V7"...
Starting: Intent { cmp=com.example.trusdkreactnative/.MainActivity }
✨ Done in 119.80s.

This will run a Metro server in a new terminal tab or window and install the React Native application to your USB connected Android application.

Install and run the React App on iOS (MacOS only)


Detailed information on running an application on a device can be found in the

React Native documentation


Run the Metro development server:

yarn start # or npm start

Install the project dependencies:

cd ios && pod install

Ensure your iOS device is connected via USB. Open up ios/TruSdkReactNativeExample.xcworkspace in XCode and set your iOS device as your deployment target:

Setting Deployment Target in XCode

Finally, select "Run" in XCode to install and run the application on your iOS device.

5. Perform a SubscriberCheck

Enter your phone number including the country code and click "Verify my phone number". The application will look similar to the following:

phone device wrapper

With that, you've completed your first SubscriberCheck from a React Native application.

6. Resources

7. Troubleshooting

Error: Could not find or load main class org.gradle.wrapper.GradleWrapperMain when running yarn android

The gradle wrapper is missing, broken or corrupted.

Ensure Gradle is installed and fex the gradle wrapper by running the following in the terminal from the android directory:

gradle wrapper

For more information see this Stack Overflow answer.

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