Real-time Transcript Updates

During an AI Assistant conversation, the SDK provides real-time transcript updates that include both the caller's speech and the AI Assistant's responses. This allows you to display a live conversation transcript in your application.

To receive transcript updates, set up the onTranscriptUpdate callback on your TelnyxClient instance:

_telnyxClient.onTranscriptUpdate = (List<TranscriptItem> transcript) {
  // Handle the updated transcript
  for (var item in transcript) {
    print('${item.role}: ${item.content}');
    // item.role will be either 'user' or 'assistant'
    // item.content contains the spoken text
    // item.timestamp contains when the message was received
  }
  
  // Update your UI to display the conversation
  setState(() {
    _conversationTranscript = transcript;
  });
};

The TranscriptItem class contains the following properties:

Property	Type	Description
id	String	Unique identifier for the transcript item
role	String	Either 'user' (for the caller) or 'assistant' (for the AI Agent)
content	String	The transcribed text content
timestamp	DateTime	When the transcript item was created

You can manually retrieve the current transcript at any time:

List<TranscriptItem> currentTranscript = _telnyxClient.transcript;

// Process the transcript
for (var item in currentTranscript) {
  print('${item.timestamp}: [${item.role}] ${item.content}');
}

To clear the transcript (for example, when starting a new conversation):

_telnyxClient.clearTranscript();

class TranscriptWidget extends StatefulWidget {
  @override
  _TranscriptWidgetState createState() => _TranscriptWidgetState();
}

class _TranscriptWidgetState extends State<TranscriptWidget> {
  List<TranscriptItem> _transcript = [];

  @override
  void initState() {
    super.initState();
    
    // Set up transcript updates
    _telnyxClient.onTranscriptUpdate = (List<TranscriptItem> transcript) {
      setState(() {
        _transcript = transcript;
      });
    };
  }

  @override
  Widget build(BuildContext context) {
    return ListView.builder(
      itemCount: _transcript.length,
      itemBuilder: (context, index) {
        final item = _transcript[index];
        return ListTile(
          leading: Icon(
            item.role == 'user' ? Icons.person : Icons.smart_toy,
            color: item.role == 'user' ? Colors.blue : Colors.green,
          ),
          title: Text(item.content),
          subtitle: Text(
            '${item.role} • ${item.timestamp.toString()}',
            style: TextStyle(fontSize: 12),
          ),
        );
      },
    );
  }
}

class ChatTranscriptWidget extends StatefulWidget {
  @override
  _ChatTranscriptWidgetState createState() => _ChatTranscriptWidgetState();
}

class _ChatTranscriptWidgetState extends State<ChatTranscriptWidget> {
  List<TranscriptItem> _transcript = [];
  ScrollController _scrollController = ScrollController();

  @override
  void initState() {
    super.initState();
    
    _telnyxClient.onTranscriptUpdate = (List<TranscriptItem> transcript) {
      setState(() {
        _transcript = transcript;
      });
      
      // Auto-scroll to bottom
      WidgetsBinding.instance.addPostFrameCallback((_) {
        if (_scrollController.hasClients) {
          _scrollController.animateTo(
            _scrollController.position.maxScrollExtent,
            duration: Duration(milliseconds: 300),
            curve: Curves.easeOut,
          );
        }
      });
    };
  }

  @override
  Widget build(BuildContext context) {
    return ListView.builder(
      controller: _scrollController,
      itemCount: _transcript.length,
      itemBuilder: (context, index) {
        final item = _transcript[index];
        final isUser = item.role == 'user';
        
        return Align(
          alignment: isUser ? Alignment.centerRight : Alignment.centerLeft,
          child: Container(
            margin: EdgeInsets.symmetric(vertical: 4, horizontal: 8),
            padding: EdgeInsets.all(12),
            decoration: BoxDecoration(
              color: isUser ? Colors.blue[100] : Colors.grey[200],
              borderRadius: BorderRadius.circular(16),
            ),
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              mainAxisSize: MainAxisSize.min,
              children: [
                Text(
                  item.content,
                  style: TextStyle(fontSize: 16),
                ),
                SizedBox(height: 4),
                Text(
                  DateFormat('HH:mm:ss').format(item.timestamp),
                  style: TextStyle(fontSize: 10, color: Colors.grey[600]),
                ),
              ],
            ),
          ),
        );
      },
    );
  }

  @override
  void dispose() {
    _scrollController.dispose();
    super.dispose();
  }
}

_telnyxClient.onTranscriptUpdate = (List<TranscriptItem> transcript) {
  // Filter only user messages
  List<TranscriptItem> userMessages = transcript
      .where((item) => item.role == 'user')
      .toList();
  
  // Filter only assistant messages
  List<TranscriptItem> assistantMessages = transcript
      .where((item) => item.role == 'assistant')
      .toList();
  
  // Process latest message
  if (transcript.isNotEmpty) {
    TranscriptItem latestMessage = transcript.last;
    if (latestMessage.role == 'assistant') {
      // Handle new assistant response
      _handleAssistantResponse(latestMessage);
    }
  }
};

class TranscriptManager {
  static const String _storageKey = 'conversation_transcripts';
  
  static Future<void> saveTranscript(
    String conversationId,
    List<TranscriptItem> transcript,
  ) async {
    final prefs = await SharedPreferences.getInstance();
    
    // Convert to JSON
    List<Map<String, dynamic>> transcriptJson = transcript
        .map((item) => {
              'id': item.id,
              'role': item.role,
              'content': item.content,
              'timestamp': item.timestamp.toIso8601String(),
            })
        .toList();
    
    // Save to storage
    Map<String, dynamic> allTranscripts = 
        jsonDecode(prefs.getString(_storageKey) ?? '{}');
    allTranscripts[conversationId] = transcriptJson;
    
    await prefs.setString(_storageKey, jsonEncode(allTranscripts));
  }
  
  static Future<List<TranscriptItem>?> loadTranscript(
    String conversationId,
  ) async {
    final prefs = await SharedPreferences.getInstance();
    Map<String, dynamic> allTranscripts = 
        jsonDecode(prefs.getString(_storageKey) ?? '{}');
    
    if (!allTranscripts.containsKey(conversationId)) return null;
    
    List<dynamic> transcriptJson = allTranscripts[conversationId];
    return transcriptJson.map((item) => TranscriptItem(
      id: item['id'],
      role: item['role'],
      content: item['content'],
      timestamp: DateTime.parse(item['timestamp']),
    )).toList();
  }
}

• AI Assistant Only: Transcript updates are only available during AI Assistant conversations initiated through anonymousLogin
• Real-time Updates: Transcripts are updated in real-time as the conversation progresses
• Persistent: The transcript persists throughout the call duration
• Memory Management: Consider clearing transcripts for long conversations to manage memory
• Text Messages: Text messages sent via sendConversationMessage also appear in the transcript

If you're not receiving transcript updates:

1. Ensure you're using anonymousLogin (not regular authentication)
2. Verify the onTranscriptUpdate callback is set before starting the call
3. Check that the AI assistant is properly configured for transcription
4. Confirm the call is active and connected

If some messages are missing from the transcript:

1. Check network connectivity during the call
2. Ensure the callback isn't being overridden
3. Verify the AI assistant is configured to provide transcripts

• Send text messages to the AI agent during calls