firetell_flutter_sdk 1.0.2

Firetell WebRTC VoIP SDK for Flutter — audio calls, hold, mute, DTMF, transfer, and VoIP push notifications (FCM & APNs) with native WebSocket event-based signaling.

Firetell Flutter WebRTC SDK

A Flutter SDK for building VoIP-enabled mobile applications with the Firetell platform. Supports audio calls, hold, mute, DTMF, call transfer, and VoIP push notifications (FCM & APNs) with native WebSocket event-based signaling.

Features

• Authentication — Workspace domain + JWT-based authentication
• Outbound Calls — Initiate calls via REST API + WebRTC
• Incoming Calls — Accept/reject via WebSocket or VoIP push notifications
• Call Controls — Mute, hold/unhold, DTMF, transfer
• VoIP Push — FCM (Android) and APNs VoIP (iOS) push notification support
• Full ICE — Complete ICE candidate gathering before SDP exchange
• Real-time Events — SSE stream for workspace events (agent state, call ring, etc.)

Installation

Add to your pubspec.yaml:

dependencies:
  firetell_flutter_sdk:
    git:
      url: https://github.com/firetellcom/firetell-flutter-sdk.git
      ref: main

Quick Start

1. Initialize the Client

import 'package:firetell_flutter_sdk/firetell_flutter_sdk.dart';

final client = FiretellClient(
  jwt: 'your_agent_jwt_token',
  domain: 'your_workspace.firetell.app',
);

// Wait for initialization
final session = await client.ready;
print('Connected as ${session.username}');

2. Make an Outbound Call

final call = await client.makeOutboundCall(
  to: '[phone]',
  from: '1001', // Optional caller extension
);

// Listen for call state changes
call.onStateChange.listen((event) {
  print('Call state: ${event.state}');
  if (event.state == CallState.active) {
    print('Call connected!');
  }
});

// Hang up
await call.hangup();

3. Handle Incoming Calls (SSE — Foreground)

client.onCallRing.listen((params) {
  print('Incoming call from ${params.callerName} (${params.callerNumber})');
  // Show incoming call UI...
});

client.onCallOffer.listen((call) async {
  // User taps "Answer"
  await call.accept();
});

4. Handle Incoming Calls (VoIP Push — Background)

// Parse the push payload
final ringParams = CallRingParams.fromFcmData(pushData);

// Show native incoming call UI via flutter_callkit_incoming
// ...

// When user answers:
final call = await client.handlePushIncomingCall(ringParams);
await call.accept();

// When user declines (fast HTTP reject, no WS needed):
final tempCall = Call(iceServers: client.iceServers);
tempCall.callId = ringParams.callId;
await tempCall.rejectViaHttp(
  baseUrl: client.baseUrl,
  callToken: ringParams.callToken,
);

5. Register Push Tokens

// Register VoIP push token (on every cold launch / token refresh)
await PushTokenService.registerVoipPushToken(
  baseUrl: client.baseUrl,
  jwt: client.jwt,
  pushToken: fcmToken, // or APNs VoIP token
  deviceId: await DeviceIdHelper.getOrCreate(),
  platform: 'android', // or 'ios'
);

// Register notification token (for call.canceled / call.ended dismissal)
await PushTokenService.registerNotificationPushToken(
  baseUrl: client.baseUrl,
  jwt: client.jwt,
  notificationToken: fcmToken,
  deviceId: await DeviceIdHelper.getOrCreate(),
  platform: 'android',
);

Call Controls

// Mute / Unmute
await call.mute();
await call.unmute();
await call.toggleMute();

// Hold / Unhold
await call.onhold();
await call.unhold();

// DTMF
call.sendDTMF('1');
call.sendDTMF('#');

// Transfer
await call.transfer('[phone]', reason: 'Customer request');

// Hang up
await call.hangup();

Call State Machine

Outbound: none → initiated → ringing → answered → active → ended
Inbound:  none → ringing → answered → active → ended
Hold:     active ↔ onHold

WebSocket Signaling Protocol

The SDK uses the same native WebSocket event-based JSON signaling protocol as the Firetell browser SDK:

Event	Direction	Description
session.connect	Client → Server	Authenticate with call_token (must be within 3s)
session.connected	Server → Client	Authentication ACK
call.offer	Client → Server	SDP Offer
call.answer	Client → Server	SDP Answer
call.hold	Client → Server	Hold call (with renegotiated SDP)
call.unhold	Client → Server	Unhold call (with renegotiated SDP)
call.hangup	Client → Server	End call
call.reject	Client → Server	Reject incoming call
call.mute	Client → Server	Mute/unmute notification
call.dtmf	Client → Server	DTMF digit
call.transfer	Client → Server	Transfer call

Architecture

FiretellClient
├── REST API (POST /api/v1/call-center/calls → call_id, call_token, ws_url)
├── SSE Stream (GET /stream → real-time workspace events)
└── Call (per-call instance)
    ├── Native WebSocket (ws_url, authenticated via call_token)
    └── RTCPeerConnection (flutter_webrtc, Full ICE)

Platform Setup

Android

Add to 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" />

iOS

Add to Info.plist:

<key>NSMicrophoneUsageDescription</key>
<string>Firetell needs microphone access for VoIP calls</string>
<key>UIBackgroundModes</key>
<array>
  <string>voip</string>
  <string>fetch</string>
  <string>remote-notification</string>
</array>

License

MIT — see LICENSE for details.