Get Started with SubscriberCheck on Flutter

Get Started with Flutter

This guide walks you through what is required on your Flutter app in order to perform a SubscriberCheck using tru.ID's Flutter 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 Flutter SDK

The tru.ID Flutter 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 pubspec.yaml, under the dependencies add the tru.ID's Flutter SDK:

`tru_sdk_flutter: ^0.1.2`

Run the command below to install this dependency into your project:

flutter pub get

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 'package:tru_sdk_flutter/tru_sdk_flutter.dart';

Define an instance of the tru.ID SDK:

TruSdkFlutter sdk = TruSdkFlutter();


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

await sdk.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 sdk.checkUrlWithResponseBody(checkUrl);

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 Flutter example application


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

Flutter 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:

flutter run

The terminal output will look similar to the following:

Launching lib/main.dart on Greg’s iPhone in debug mode...
Automatically signing iOS for device deployment using specified development team in Xcode project: <project>
Running Xcode build...
└─Compiling, linking and signing... 3.3s
Xcode build done. 16.4s
Installing and launching... 13.8s
Syncing files to device Greg’s iPhone... 80ms
Flutter run key commands.
r Hot reload. 🔥🔥🔥
R Hot restart.
h List all available interactive commands.
d Detach (terminate "flutter run" but leave application running).
c Clear the screen
q Quit (terminate the application on the device).

5. Perform a SubscriberCheck

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

phone device wrapper

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

6. Resources

Download our Developer Console mobile app
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