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.
Two Configuration Surfaces
| Surface | When | What | Mutable? |
|---|
| Query parameters | WebSocket URL | Voice selection, audio format, sample rate, connection options | No — locked at connect |
voice_settings | Init frame ({"text": " "}) | Provider-specific tuning (speed, pitch, format, etc.) | No — locked at init |
Query Parameters
Set on the URL at connect time. Immutable for the session.
Voice Selection
| Parameter | Type | Default | Description |
|---|
voice | string | — | Voice identifier in Provider.Model.VoiceId format. |
voice_id segment (third part of the voice string) refers to different things depending on the provider and model:
| Type | Example | How you get it |
|---|
| Pre-built voice | Telnyx.NaturalHD.astra | Browse via the Voices API or Voice Design Lab. Shipped by the provider — available to everyone. |
| Your cloned voice | Telnyx.Qwen3TTS.my-ceo-clone | Create in the Voice Design Lab. Scoped to your organization — only your API key can use it. Available for Qwen3TTS and Minimax. |
| BYOK provider voice | elevenlabs.v3.Adam | A voice ID from your own ElevenLabs or Resemble account. You bring your own API key; Telnyx relays the request. |
GET /v2/ai/tts/voices) returns all voices available to your account — pre-built and cloned — with each voice’s compound id ready to use as the voice parameter.
Connection Options
| Parameter | Type | Default | Description |
|---|
language | string | — | BCP-47 language code. Passed to the provider as language_code. Only used by providers that accept it (AWS Polly, Azure, ElevenLabs, Inworld). |
text_type | string | text | Text type hint: text or ssml. Only AWS Polly and Azure use this. |
audio_format | string | mp3 | Output audio format: mp3, linear16, wav, mulaw, alaw, ogg_vorbis. Not all formats are supported by every provider — see providers dedicated pages. |
sample_rate | integer | provider default | Output sample rate in Hz. Accepted values vary by provider — see providers dedicated pages. |
disable_cache | boolean | false | Bypass the audio cache and always synthesize fresh. |
Example
wss://api.telnyx.com/v2/text-to-speech/speech?voice=Telnyx.NaturalHD.astra&audio_format=linear16&disable_cache=true
Voice Settings
Provider-specific tuning (speed, pitch, format, emotion, etc.) is not set via query parameters. It is passed once in the voice_settings object on the initialization frame:
{
"text": " ",
"voice_settings": {
"voice_speed": 1.2,
"emotion": "happy"
}
}
