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POST
Text-to-Speech (Bytes)

Authorizations

Authorization
string
header
default:$CARTESIA_API_KEY
required

Cartesia API key (sk_car_...). Get one at play.cartesia.ai/keys.

Headers

Cartesia-Version
enum<string>
default:2026-08-14
required

API version header.

Available options:
2026-08-14
Example:

"2026-08-14"

Body

application/json
model_id
enum<string>
default:sonic-3.5
required

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

Available options:
sonic-3.5,
sonic-3,
sonic-latest
Example:

"sonic-3.5"

transcript
string
default:Hi there, it's awesome to meet you.
required
voice
required

The ID of the voice.

Example:

"db6b0ed5-d5d3-463d-ae85-518a07d3c2b4"

output_format
WAVOutputFormat · object
required
language
enum<string> | null

Prefer locale when you can. language only accepts base ISO codes like en. A request may set language or locale, never both.

Available options:
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,
or,
ur
locale
string | null

Prefer locale over language (for example en-GB). language only accepts base codes like en. locale also accepts regional codes like en-GB. Locale codes need Sonic 3.6+. A request may set language or locale, never both.

normalization
string | null

Text normalization. auto (default) runs the locale-aware normalizer, off skips it, or pass a locale code (for example en-IN) to pin the normalizer independently of the generation language. See Text Normalization.

pronunciation_dict_id
string | null

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

generation_config
GenerationConfig · object

Configure the various attributes of the generated speech. Available on sonic-3 and sonic-3.5; not available on earlier models.

See Volume, Speed, and Emotion for a guide on this option.

Response

200 - audio/*

Audio bytes

The response is of type file.