CAcartesia
Tts

Text-to-Speech (SSE)

Stream audio with extra metadata from a complete transcript

post/tts/sse

Request

Headers

Cartesia-Version'2026-03-01' date required
Example:2026-03-01

API version header.

Request body

model_id'sonic-3.5' | 'sonic-3' | 'sonic-latest' required

The ID of the model to use for the generation. See Models all options.

transcriptstring required
language'en' | 'fr' | 'de' | 'es' | 'pt' | 'zh' | 'ja' | 'hi' | 'it' | 'ko' | 'nl' | 'pl' | 'ru' | 'sv' | 'tr' | 'tl' | 'bg' | 'ro' | 'ar' | 'cs' | 'el' | 'fi' | 'hr' | 'ms' | 'sk' | 'da' | 'ta' | 'uk' | 'hu' | 'no' | 'vi' | 'bn' | 'th' | 'he' | 'ka' | 'id' | 'te' | 'gu' | 'kn' | 'ml' | 'mr' | 'pa'

The language that the given voice should speak the transcript in. This may depend on the model you're using. See Models for details.

add_timestampsboolean nullable

Whether to return word-level timestamps. If false (default), no word timestamps will be produced at all. If true, the server will return timestamp events containing word-level timing information.

add_phoneme_timestampsboolean nullable

Whether to return phoneme-level timestamps. If false (default), no phoneme timestamps will be produced. If true, the server will return timestamp events containing phoneme-level timing information.

use_normalized_timestampsboolean nullable

Whether to use normalized timestamps (True) or original timestamps (False).

pronunciation_dict_idstring nullable

The ID of a pronunciation dictionary to use for the generation. Pronunciation dictionaries are supported by sonic-3 models and newer.

speed'slow' | 'normal' | 'fast'

This property is deprecated and may not work for all voices. Use generation_config.speed instead. Influences the speed of the generated speech.

context_idstring nullable

Example request

{
  "model_id": "sonic-3.5"
}

Response

Server-sent events stream. Each frame is data: <json>\n\n where the JSON payload matches TTSSSEEvent.

Changes

No recorded changes to this operation across all 1 revision of this API.