iProov: Flexible authentication for identity assurance

iProov Biometrics Flutter SDK


The iProov Biometrics Flutter SDK wraps iProov's native iOS (Swift) and Android (Java) SDKs behind a Dart interface for use from within your Flutter iOS or Android app.

We also provide an API Client written in Dart to call our REST API v2 from a Flutter app, which can be used from your Flutter app to request tokens directly from the iProov API (note that this is not a secure way of getting tokens, and should only be used for demo/debugging purposes).


  • Dart SDK 2.15 and above
  • Flutter SDK 1.20 and above
  • iOS 12 and above
  • Android API Level 21 (Android 5 Lollipop) and above

Repository contents

The iProov Flutter SDK is provided via this repository, which contains the following:

  • README.md - This document
  • example - A demonstration Flutter App
  • iproov_api_client - The Dart iProov API Client
  • lib - Folder containing the Flutter (Dart) side of the SDK Plugin
  • android - Folder containing the Android (Kotlin) native side of the SDK Plugin
  • ios - Folder containing the iOS (Swift) native side of the SDK Plugin


You can obtain API credentials by registering on iPortal.


Add the following to your project's pubspec.yaml file:

  iproov_flutter: ^4.0.2

You can then install it with:

flutter pub get

iOS installation

You must also add a NSCameraUsageDescription to your iOS app's Info.plist, with the reason why your app requires camera access (e.g. β€œTo iProov you in order to verify your identity.”).

Get started

Once you have a valid token (obtained via the Dart API client or your own backend-to-backend call), you can launch() an iProov capture and handle the callback events as they arrive in the Stream<IProovEvent>.

import 'package:iproov_flutter/iproov_flutter.dart';

// Streaming URL provided for example only (substitute as appropriate)
final stream = IProov.launch(streamingUrl: 'wss://eu.rp.secure.iproov.me/ws', token: '< YOUR TOKEN >');
stream.listen((event) {

  if (event is IProovEventConnecting) {
    // The SDK is connecting to the server. You should provide an indeterminate progress indicator
    // to let the user know that the connection is taking place.
  } else if (event is IProovEventConnected) {
    // The SDK has connected, and the iProov user interface will now be displayed. You should hide
    // any progress indication at this point.
  } else if (event is IProovEventProcessing) {
    // The SDK will update your app with the progress of streaming to the server and authenticating
    // the user. This will be called multiple times as the progress updates.
    final progress = event.progress; // Progress between 0.0 and 1.0
    final message = event.message; // Message to be displayed to the user
  } else if (event is IProovEventSuccess) {
    // The user was successfully verified/enrolled and the token has been validated.
    // You can access the following properties:
    final frame = result.frame; // An optional image containing a single frame of the user, if enabled for your service provider
  } else if (event is IProovEventCanceled) {
    // The user canceled iProov, either by pressing the close button at the top of the screen, or sending
    // the app to the background. (event.canceler == Canceler.user)
    // Or, the app canceled (event.canceler == Canceler.app) by canceling the subscription to the 
    // Stream returned from IProov.launch().
    // You should use this to determine the next step in your flow.
    final canceler = event.canceler;
  } else if (event is IProovEventFailure) {
    // The user was not successfully verified/enrolled, as their identity could not be verified,
    // or there was another issue with their verification/enrollment. A reason (as a string)
    // is provided as to why the claim failed, along with a feedback code from the back-end.
    final feedbackCode = event.feedbackCode;
    final reason = event.reason;
    final frame = result.frame; // An optional image containing a single frame of the user, if enabled for your service provider
  } else if (event is IProovEventError) {
    // The user was not successfully verified/enrolled due to an error (e.g. lost internet connection).
    // You will be provided with an Exception (see below).
    // It will be called once, or never.
    final error = event.error // IProovException provided by the SDK

πŸ‘‰ You should now familiarize yourself with the following resources:

These repositories provide comprehensive documentation about the available customization options and other important details regarding the SDK usage.

Canceling the SDK

Under normal circumstances, the user will be in control of the completion of the iProov scan, i.e. they will either complete the scan, or use the close button to cancel. In some cases, you (the integrator) may wish to cancel the iProov scan programmatically, for example in response to a timeout or change of conditions in your app.

The scan can now be closed doing IProov.cancel(). Also canceling all subscriptions to the Stream<IProovEvent> returned from IProov.launch() will cancel any ongoing claim.


final stream = IProov.launch(streamingUrl: 'wss://eu.rp.secure.iproov.me/ws', token: '< YOUR TOKEN >');
final subscription = stream.listen((event) { ... });



The Options class allows iProov to be customized in various ways. These can be specified by passing the optional options: named parameter in IProov.launch().

Most of these options are common to both Android and iOS, however, some are Android-only.

For full documentation, please read the respective iOS and Android native SDK documentation.

A summary of the support for the various SDK options in Flutter is provided below. All options are nullable and any options not set will default to their platform-defined default value.

Option Type iOS Android
filter Filter? (See filter options) βœ… βœ…
titleTextColor Color? βœ… βœ…
promptTextColor Color? βœ… βœ…
closeButtonTintColor Color? βœ… βœ…
closeButtonImage Image? βœ… βœ…
title String? βœ… βœ…
fontPath (*) String? βœ… βœ…
logoImage Image? βœ… βœ…
promptBackgroundColor Color? βœ… βœ…
promptRoundedCorners bool? βœ… βœ…
surroundColor Color? βœ… βœ…
certificates List<String>? βœ… βœ…
timeout Duration? βœ… βœ…
enableScreenshots bool? βœ…
orientation Orientation? βœ…
camera Camera? βœ…
headerBackgroundColor Color? βœ… βœ…
disableExteriorEffects bool? βœ… βœ…
genuinePresenceAssurance GenuinePresenceAssuranceOptions?
↳ readyOvalStrokeColor Color? βœ… βœ…
↳ notReadyOvalStrokeColor Color? βœ… βœ…
livenessAssurance LivenessAssuranceOptions?
↳ ovalStrokeColor Color? βœ… βœ…
↳ completedOvalStrokeColor Color? βœ… βœ…

(*) Fonts should be added to your Flutter app (TTF or OTF formats are supported). Note that the font filename must match the font name.


const options = Options(fontPath: 'fonts/Lobster-Regula.ttf');

Filter Options

The SDK supports two different camera filters:


LineDrawingFilter is iProov's traditional "canny" filter, which is available in 3 styles: .shaded (default), .classic and .vibrant.

The foregroundColor and backgroundColor can also be customized.


const options = Options(
      filter: LineDrawingFilter(
          style: LineDrawingFilterStyle.vibrant,
          foregroundColor: Colors.black,
          backgroundColor: Colors.white


NaturalFilter provides a more direct visualization of the user's face and is available in 2 styles: .clear (default) and .blur.


const options = Options(
      filter: NaturalFilter(
          style: NaturalFilterStyle.clear

Note: NaturalFilter is available for Liveness Assurance claims only. Attempts to use NaturalFilter for Genuine Presence Assurance claims will result in an error.

Handling errors

All errors from the native SDKs are re-mapped to Flutter exceptions:

Exception iOS Android Description
CaptureAlreadyActiveException βœ… βœ… An existing iProov capture is already in progress. Wait until the current capture completes before starting a new one.
NetworkException βœ… βœ… An error occurred with the video streaming process. Consult the message value for more information.
CameraPermissionException βœ… βœ… The user disallowed access to the camera when prompted. You should direct the user to re-enable camera access.
ServerException βœ… βœ… A server-side error/token invalidation occurred. The associated message will contain further information about the error.
UnexpectedErrorException βœ… βœ… An unexpected and unrecoverable error has occurred. These errors should be reported to iProov for further investigation.
UnsupportedDeviceException βœ… βœ… Device is not supported.
ListenerNotRegisteredException βœ… The SDK was launched before a listener was registered.
MultiWindowUnsupportedException βœ… The user attempted to iProov in split-screen/multi-screen mode, which is not supported.
CameraException βœ… An error occurred acquiring or using the camera. This could happen when a non-phone is used with/without an external/USB camera.
FaceDetectorException βœ… An error occurred with the face detector.
InvalidOptionsException βœ… An error occurred when trying to apply your options.
UserTimeoutException βœ… The user has taken too long to complete the claim.

API Client

The Dart API Client (iproov_api_client) provides a convenient wrapper to call iProov's REST API v2 from your Flutter app. It is a useful tool to assist with testing, debugging and demos, but should not be used in production mobile apps. You can also use this code as a reference for your back-end implementation to perform server-to-server calls.

The Dart API client package can be found in the iproov_api_client folder. You can add it to your project as follows:

      url: git@github.com:iProov/flutter-sdk.git
      path: iproov_api_client


Use of the Dart API Client requires providing it with your API secret. You should never embed your API secret within a production app.


The Dart API Client supports the following functionality:

  • getToken() - Get an enrol/verify token.
  • enrolPhoto() - Perform a photo enrolment (either from an electronic or optical image). The image must be provided as an Image.
  • enrolPhotoAndGetVerifyToken() - A convenience method which first gets an enrolment token, then enrols the photo against that token, and then gets a verify token for the user to iProov against.
  • validate() - Validates a token after the claim has completed.

Getting a token

The most basic thing you can do with the API Client is get a token to either enrol or verify a user, using either iProov's Genuine Presence Assurance or Liveness Assurance.

This is achieved as follows:

import 'package:iproov_api_client/iproov_api_client.dart';

final apiClient = const ApiClient(
  baseUrl: 'https://eu.rp.secure.iproov.me/api/v2', // Substitute URL as appropriate
  apiKey: '< YOUR API KEY >',
  secret: '< YOUR SECRET >',

final token = await apiClient.getToken(
  assuranceType: AssuranceType.genuinePresenceAssurance,
  claimType: ClaimType.enrol,
  userId: "name@example.com",

You can then launch the iProov SDK with this token.

Sample code

For a simple iProov experience that is ready to run out-of-the-box, check out the Flutter example project which also makes use of the Dart API Client.

In the example app folder, copy the credentials.example.dart file to credentials.dart and add your credentials obtained from the iProov portal.

NOTE: iProov is not supported on the iOS or Android simulator, you must use a physical device in order to iProov.

Help & support

You may find your question is answered in the documentation of our native SDKs:

For further help with integrating the SDK, please contact support@iproov.com.