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Stream speech to text over WebSocket
AsyncAPI specification for the Telnyx Speech-to-Text WebSocket endpoint. Real-time speech transcription by streaming audio and receiving transcript frames.
Supported Engines
Azure- Microsoft Azure Speech ServicesDeepgram- Deepgram Nova modelsGoogle- Google Cloud Speech-to-TextTelnyx- Telnyx native transcription (OpenAI Whisper models)xAI- xAI Grok STT
Connection Flow
- Open WebSocket connection to
wss://api.telnyx.com/v2/speech-to-text/transcriptionwith query parameters. - Send binary audio frames (mp3 or wav format).
- Receive JSON transcript frames with
transcript,is_final, andconfidencefields. - Close connection when done.
Authentication
Requires authentication via a Bearer token (Telnyx API v2 key).
Documentation Index
Fetch the complete documentation index at: https://developers.telnyx.com/llms.txt
Use this file to discover all available pages before exploring further.
{}{
"type": "transcript",
"transcript": "Hello, this is",
"is_final": false,
"confidence": 0.85
}{
"type": "error",
"error": "Invalid transcription_engine specified"
}Telnyx API v2 Bearer token authentication.
Query parameters passed when opening the WebSocket connection.
Client-to-server binary frame containing audio data to transcribe. Audio should be in mp3 or wav format as specified in the input_format query parameter.
Server-to-client frame containing a transcription result. When interim_results is enabled, you may receive multiple interim results (is_final=false) before the final result (is_final=true) for each utterance.
Server-to-client frame indicating an error during transcription. The connection may be closed shortly after sending this frame.
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{}{
"type": "transcript",
"transcript": "Hello, this is",
"is_final": false,
"confidence": 0.85
}{
"type": "error",
"error": "Invalid transcription_engine specified"
}