Create Speech with Timing

POST 
https://api.knoxstudio.ai/v1/text-to-speech/:voice_id/with-timestamps

Same body as Create speech. Returns JSON with base64 audio and character alignments instead of raw bytes. WAV formats are allowed. Billed per character.

Request

Path Parameters

Name	Type	Required	Description
voice_id	String	Yes	ElevenLabs voice ID.

Query Parameters

Name	Type	Required	Description
enable_logging	Boolean	No	Default true. false requests zero-retention mode.
optimize_streaming_latency	Integer	No	Deprecated. 0–4 latency/quality tradeoff.
output_format	String	No	Default mp3_44100_128. Format is codec_sample_rate_bitrate.

Allowed output_format (includes WAV): alaw_8000, mp3_22050_32, mp3_24000_48, mp3_44100_128, mp3_44100_192, mp3_44100_32, mp3_44100_64, mp3_44100_96, opus_48000_128, opus_48000_192, opus_48000_32, opus_48000_64, opus_48000_96, pcm_16000, pcm_22050, pcm_24000, pcm_32000, pcm_44100, pcm_48000, pcm_8000, ulaw_8000, wav_16000, wav_22050, wav_24000, wav_32000, wav_44100, wav_48000, wav_8000.

Request Headers

Name	Type	Required	Description
Authorization	String	Yes	Bearer <token> Knox API key. xi-api-key is also accepted.
Content-Type	String	Yes	application/json.

Request Body

Same fields as Create speech.

cURL Example

curl -X POST "https://api.knoxstudio.ai/v1/text-to-speech/21m00Tcm4TlvDq8ikWAM/with-timestamps" \
     -H "Authorization: Bearer $KNOXCHAT_API_KEY" \
     -H "Content-Type: application/json" \
     -d '{
  "text": "Sync this line to captions.",
  "model_id": "eleven_multilingual_v2"
}'

Response

Success Response (200)

| audio_base64 | string | Base64-encoded audio. | | alignment | object | Character timings for the original text: characters, character_start_times_seconds, character_end_times_seconds. | | normalized_alignment | object | Same shape for normalized text. |

Error Responses

Validation uses HTTP 422:

{
  "detail": [
    {
      "loc": ["body", "field"],
      "msg": "…",
      "type": "value_error"
    }
  ]
}

Other errors use { "detail": "message" }.

Status	When
400	WebSocket path called without Upgrade: websocket.
401	Missing or invalid API key.
402	Insufficient credits.
403	Token is not allowed to use this model.
404	Resource not found.
422	Validation error.
429	Rate limit exceeded.
500	Internal server error.