Voximplant Flutter SDK for embedding voice 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>

This entry allows your app to access the microphone.


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';

Client client = Voximplant().getClient();

Connect and log in to the Voximplant Cloud

The Client.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 {
    ClientState clientState = await _client.getClientState();
    if (clientState == ClientState.LoggedIn) {
      return _displayName;
    if (clientState == ClientState.Disconnected) {
      await _client.connect();
    AuthResult authResult = await _client.login(username, password);
    _displayName = authResult.displayName;
    return _displayName;

Make calls

To initiate a call we need the Client.call method. There is a CallSettings 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 Call class instance as the class contains all the functionality for call management.

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

AudioDeviceManager 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 AudioDevice enum.

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

To select an audio device:

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

  _onAudioDeviceChange(AudioDevice audioDevice) {
    // audio device is changed


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