Voximplant Flutter SDK for embedding voice and video communication into Flutter applications.




Add flutter_voximplant as a dependency in your pubspec.yaml file.


Add the following entry to your Info.plist file, located in <project root>/ios/Runner/Info.plist:

<string>Microphone is required to make audio calls</string>
<string>Camera is required to make video calls</string>

This entry allows your app to access the microphone and cameras.


It is required to add Java 8 support.

Open <project root>android/app/build.gradle file and add the following lines to ‘android’ section:

compileOptions {
    sourceCompatibility JavaVersion.VERSION_1_8
    targetCompatibility JavaVersion.VERSION_1_8


To get started, you'll need to register a free Voximplant developer account.


Client is the main class of the SDK that provides access to Voximplant’s functions, the Voximplant().getClient() method is used to get its instance:

import 'package:flutter_voximplant/flutter_voximplant.dart';

VIClient client = Voximplant().getClient();

Connect and log in to the Voximplant Cloud

The VIClient.getClientState() method is used to get the current state of connection to the Voximplant cloud and perform the actions according to it.

  Future<String> loginWithPassword(String username, String password) async {
    VIClientState clientState = await _client.getClientState();
    if (clientState == VIClientState.LoggedIn) {
      return _displayName;
    if (clientState == VIClientState.Disconnected) {
      await _client.connect();
    VIAuthResult authResult = await _client.login(username, password);
    _displayName = authResult.displayName;
    return _displayName;

Make calls

To initiate a call we need the VIClient.call method. There is a VICallSettings class which could contain custom data and extra headers (SIP headers).

Since the call can behave in different ways, there is a group of call events. They can be triggered by the VICall class instance as the class contains all the functionality for call management.

  Future<VICall> makeAudioCall(String number) async {
     VICall call = await _client.call(number);
     call.onCallDisconnected = _onCallDisconnected;
     call.onCallFailed = _onCallFailed;
     call.onCallConnected = _onCallConnected;
     call.onCallRinging = _onCallRinging;
     call.onCallAudioStarted = _onCallAudioStarted;
     return call;
  _onCallConnected(VICall call, Map<String, String>? headers) {
      print('Call connected');

Receiving calls

Client.onIncomingCall is used to get incoming calls.

There are three methods for an incoming call: answer, decline and reject. An audio stream can be sent only after the answer method call.

  CallService._() {
    _client = Voximplant().getClient();
    _client.onIncomingCall = _onIncomingCall;

  _onIncomingCall(VIClient client, VICall call, bool video, Map<String, String>? headers) async {
    await call.answer();

Mid-call operations

Audio call can be put on/off hold

  _hold() async {
    try {
      await _call.hold(!_isOnHold);
      setState(() {
        _isOnHold = !_isOnHold;
    } catch (e) {


Audio device management

VIAudioDeviceManager class API allow to:

  • get all available audio devices
  • get currently selected audio device
  • select audio device
  • handle active audio device changes and new audio devices (for example, Bluetooth headset or wired headset connection). These changes trigger the appropriate events.

All types of audio devices are represented in the VIAudioDevice enum.

Note that there are platform specific nuances in audio device management.

To select an audio device:

  _selectAudioDevice(VIAudioDevice device) async{
    VIAudioDeviceManager audioDeviceManager = Voximplant().getAudioDeviceManager();
    audioDeviceManager.onAudioDeviceChanged = _onAudioDeviceChange;
    await audioDeviceManager.selectAudioDevice(device);

  _onAudioDeviceChange(VIAudioDeviceManager audioDeviceManager, AudioDevice audioDevice) {
    // audio device is changed


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