iProov: Flexible authentication for identity assurance

iProov Biometrics Flutter SDK (Preview)

Table of contents


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 2.12 and above
  • Flutter SDK 1.20 and above
  • iOS 10.0 and above
  • Android API Level 21 (Android 5 Lollipop) and above


The iProov Biometrics Flutter SDK is currently in preview, which means that there may be missing/broken functionality, and the API is still subject to change. Please contact us to provide your feedback regarding the iProov Biometrics Flutter SDK Preview.

Repository contents

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

  • README.md - This document
  • example - A demonstration Flutter App along with 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 the iProov Partner Portal.


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

  iproov_flutter: ^0.2.0

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 follows:

import 'package:iproov_flutter/iproov_flutter.dart';

IProov.launch(streamingUrl: "https://eu.rp.secure.iproov.me", // Substitute as appropriate
    token: "< YOUR TOKEN >",
    callback: (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 IProovEventProgress) {
    // The SDK will update your app with the progress of streaming to the server and authenticating
    // the user. This will be called multiple time as the progress updates.
  } else if (event is IProovEventSuccess) {
    // The user was successfully verified/enrolled and the token has been validated.
    // You can access the following properties:
    var token = result.token; // The token passed back will be the same as the one passed in to the original call
    var frame = result.frame; // An optional image containing a single frame of the user, if enabled for your service provider
  } else if (event is IProovEventCancelled) {
    // The user cancelled iProov, either by pressing the close button at the top right, or sending
    // the app to the background.
  } 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.
    var feedbackCode = event.feedbackCode;
    var reason = event.reason;
  } 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.

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

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


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 platform-specific (for example, iOS has a close button but Android does not).

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:

fontPath⚠️ (1)
fontResource⚠️ (1)
font⚠️ (1)
maxPitchβœ… (2)βœ… (2)
maxYawβœ… (2)βœ… (2)
maxRollβœ… (2)βœ… (2)

(1) There are currently different ways of setting fonts on iOS & Android. Fonts should be added to the respective iOS app bundle or Android project (android/app/src/main/res/font) and can then be set by name via this API. This is due to be revised in a future release.

(2) This is an advanced option and not recommended for general usage. If you wish to use this option, contact iProov for for further details.

Handling errors

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

CaptureAlreadyActiveExceptionβœ…βœ…An existing iProov capture is already in progress. Wait until the current capture completes before starting a new one.
NetworkErrorβœ…βœ…An error occurred with the video streaming process. Consult the message value for more information.
CameraPermissionErrorβœ…βœ…The user disallowed access to the camera when prompted. You should direct the user to re-enable camera access.
ServerExceptionβœ…βœ…A server-side error/token invalidation occurred. The associated message will contain further information about the error.
UnexpectedErrorExceptionβœ…βœ…An unexpected and unrecoverable error has occurred. These errors should be reported to iProov for further investigation.
ListenerNotRegisteredExceptionβœ…The SDK was launched before a listener was registered.
MultiWindowUnsupportedExceptionβœ…The user attempted to iProov in split-screen/multi-screen mode, which is not supported.
CameraExceptionβœ…An error occurred acquiring or using the camera. This could happen when a non-phone is used with/without an external/USB camera.
FaceDetectorExceptionβœ…An error occurred with the face detector.
InvalidOptionsExceptionβœ…An error occurred when trying to apply your options.

API Client

The Dart API Client provides a convenient wrapper to call iProov's REST API v2 from a Dart/Flutter app. It is a useful tool to assist with testing, debugging and demos, but should not be used in production mobile apps. You could also adapt this code to run on your back-end to perform server-to-server calls.

The Dart API client can be found in api_client.dart in the Example project.

Your API key and secret for the example app can be set inside api_keys.dart in the Example project.

⚠️ SECURITY NOTICE: 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.

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:

var apiClient = ApiClient(
  "https://eu.rp.secure.iproov.me/api/v2/", // Substitute URL as appropriate
  "< YOUR API KEY >",
var token = await apiClient.getToken(AssuranceType.genuinePresenceAssurance, ClaimType.enrol, "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.

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.