Vapi Flutter SDK

Minimum requirements

The Daily Client SDK for Flutter requires the following versions:

• Flutter ≥ 3.0.0
• iOS ≥ 13.0 (objective-C and Swift applications are supported)
• Android compileSdkVersion ≥ 33
• Android minSdkVersion ≥ 24
• Android NDK ≥ 25.1.8937393

Setup

Add vapi as a dependency:

flutter pub add vapi

Then, follow the platform-specific setup instructions for permission_handler:

iOS

According to the permission_handler instructions above, add the permission flags for microphone.

Also add this to your Info.plist:

<key>NSMicrophoneUsageDescription</key>
<string>This app requires access to the microphone for live audio calls.</string>

You'll also need to ensure this is set in your Podfile:

post_install do |installer|
  installer.pods_project.targets.each do |target|
    flutter_additional_ios_build_settings(target)
    target.build_configurations.each do |config|
      config.build_settings['GCC_PREPROCESSOR_DEFINITIONS'] ||= [
        '$(inherited)',

        'PERMISSION_MICROPHONE=1',
      ]
    end
  end
end

We also recommend adding the audio background mode to your app's capabilities.

Android

Add the necessary permissions to your AndroidManifest.xml:

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.RECORD_AUDIO" />
<uses-permission android:name="android.permission.MODIFY_AUDIO_SETTINGS" />

Add the permission flags for microphone according to the permission_handler instructions above.

Usage

First, import the Vapi class from the package:

import 'package:vapi/vapi.dart';

Then, create a new instance of the Vapi class, passing your Public Key as a parameter to the constructor:

var vapi = Vapi('your-public-key');

You can start a new call by calling the start method and passing an assistant object or assistantId:

await vapi.start(assistant: {
  "model": {
    "provider": "openai",
    "model": "gpt-3.5-turbo",
    "systemPrompt": "You're an assistant..."
  },
   "voice": {
    "provider": "11labs",
    "voiceId": "burt",
  },
  ...
});

await vapi.start(assistantId: "your-assistant-id");

The start method will initiate a new call.

You can override existing assistant parameters or set variables with the assistant_overrides parameter. Assume the first message is Hey, {{name}} how are you? and you want to set the value of name to John:

final assistantOverrides = {
  'recordingEnabled': false,
  'variableValues': {
    'name': 'John',
  },
};

await vapi.start(
  assistantId: 'your-assistant-id',
  assistantOverrides: assistantOverrides,
);

You can send text messages to the assistant aside from the audio input using the send method and passing appropriate role and content.

vapi.send({
  "type": "add-message",
  "message": {
    "role": "system",
    "content": "The user has pressed the button, say peanuts",
  },
});

Possible values for the role are system, user, assistant, tool or function.

You can stop the session by calling the stop method:

await vapi.stop();

This will stop the recording and close the connection.

The setMuted(muted: boolean) can be used to mute and un-mute the user's microphone.

vapi.isMuted(); // false
vapi.setMuted(true);
vapi.isMuted(); // true

Events

You can listen to the following events:

vapi.onEvent.listen((event) {
    if (event.label == "call-start") {
        print('call started');
    }
    if (event.label == "call-end") {
        print('call ended');
    }

    // Speech statuses, function calls and transcripts will be sent via messages
    if (event.label == "message") {
        print(event.value);
    }
});

These events allow you to react to changes in the state of the call or speech.

Example

An example can be found in the repo here

License

MIT License

Copyright (c) 2023 Vapi Labs Inc.

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.