Clone a voice

curl --request POST \
  --url https://api.nineninesix.ai/voices/clone \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: multipart/form-data' \
  --form clip=@example-file \
  --form 'name=<string>' \
  --form language=en-US \
  --form 'description=<string>' \
  --form 'transcript=<string>'

import requests

url = "https://api.nineninesix.ai/voices/clone"

files = { "clip": ("example-file", open("example-file", "rb")) }
payload = {
    "name": "<string>",
    "language": "en-US",
    "description": "<string>",
    "transcript": "<string>"
}
headers = {"Authorization": "Bearer <token>"}

response = requests.post(url, data=payload, files=files, headers=headers)

print(response.text)

const form = new FormData();
form.append('clip', '<string>');
form.append('name', '<string>');
form.append('language', 'en-US');
form.append('description', '<string>');
form.append('transcript', '<string>');

const options = {method: 'POST', headers: {Authorization: 'Bearer <token>'}};

options.body = form;

fetch('https://api.nineninesix.ai/voices/clone', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://api.nineninesix.ai/voices/clone",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => "-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"clip\"; filename=\"example-file\"\r\nContent-Type: application/octet-stream\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"name\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"language\"\r\n\r\nen-US\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"description\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"transcript\"\r\n\r\n<string>\r\n-----011000010111000001101001--",
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "Content-Type: multipart/form-data"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://api.nineninesix.ai/voices/clone"

	payload := strings.NewReader("-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"clip\"; filename=\"example-file\"\r\nContent-Type: application/octet-stream\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"name\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"language\"\r\n\r\nen-US\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"description\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"transcript\"\r\n\r\n<string>\r\n-----011000010111000001101001--")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("Authorization", "Bearer <token>")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.post("https://api.nineninesix.ai/voices/clone")
  .header("Authorization", "Bearer <token>")
  .body("-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"clip\"; filename=\"example-file\"\r\nContent-Type: application/octet-stream\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"name\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"language\"\r\n\r\nen-US\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"description\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"transcript\"\r\n\r\n<string>\r\n-----011000010111000001101001--")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.nineninesix.ai/voices/clone")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["Authorization"] = 'Bearer <token>'
request.body = "-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"clip\"; filename=\"example-file\"\r\nContent-Type: application/octet-stream\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"name\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"language\"\r\n\r\nen-US\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"description\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"transcript\"\r\n\r\n<string>\r\n-----011000010111000001101001--"

response = http.request(request)
puts response.read_body

{
  "id": "5148a2db-5f7c-480c-8f7c-39c6414a4d5d",
  "is_owner": false,
  "is_public": true,
  "name": "Jessica",
  "description": "Polished, quick New York professional around thirty-five, warm underneath the hustle. Jessica makes a stressful thing feel manageable.",
  "gender": "feminine",
  "language": "en-US",
  "country": "US",
  "created_at": "2026-08-14T18:26:40.876Z",
  "preview_file_url": "<string>"
}

Voices

Clone a voice

Clone a voice from a reference audio clip. Use the returned voice id in your /tts/bytes, /tts/sse, and /tts/websocket requests.

WAV is recommended; FLAC, OGG, MP3, and M4A also work. Clips must be 1–300 s and the upload under 20 MB. The server trims leading and trailing silence, uses the first 20 s of speech, and normalizes loudness. 10–20 s of clean speech works best, and the voice takes on the clip’s pace and pauses. A 48 kHz preview is rendered automatically after cloning; fetch it with GET /voices?expand[]=preview_file_url.

Errors come in two shapes: audio validation errors are { "detail": "..." }; invalid_language, clone_failed, and db_unavailable use { error, message }.

POST

voices

clone

Clone a voice

curl --request POST \
  --url https://api.nineninesix.ai/voices/clone \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: multipart/form-data' \
  --form clip=@example-file \
  --form 'name=<string>' \
  --form language=en-US \
  --form 'description=<string>' \
  --form 'transcript=<string>'

import requests

url = "https://api.nineninesix.ai/voices/clone"

files = { "clip": ("example-file", open("example-file", "rb")) }
payload = {
    "name": "<string>",
    "language": "en-US",
    "description": "<string>",
    "transcript": "<string>"
}
headers = {"Authorization": "Bearer <token>"}

response = requests.post(url, data=payload, files=files, headers=headers)

print(response.text)

const form = new FormData();
form.append('clip', '<string>');
form.append('name', '<string>');
form.append('language', 'en-US');
form.append('description', '<string>');
form.append('transcript', '<string>');

const options = {method: 'POST', headers: {Authorization: 'Bearer <token>'}};

options.body = form;

fetch('https://api.nineninesix.ai/voices/clone', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://api.nineninesix.ai/voices/clone",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => "-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"clip\"; filename=\"example-file\"\r\nContent-Type: application/octet-stream\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"name\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"language\"\r\n\r\nen-US\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"description\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"transcript\"\r\n\r\n<string>\r\n-----011000010111000001101001--",
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "Content-Type: multipart/form-data"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://api.nineninesix.ai/voices/clone"

	payload := strings.NewReader("-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"clip\"; filename=\"example-file\"\r\nContent-Type: application/octet-stream\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"name\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"language\"\r\n\r\nen-US\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"description\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"transcript\"\r\n\r\n<string>\r\n-----011000010111000001101001--")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("Authorization", "Bearer <token>")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.post("https://api.nineninesix.ai/voices/clone")
  .header("Authorization", "Bearer <token>")
  .body("-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"clip\"; filename=\"example-file\"\r\nContent-Type: application/octet-stream\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"name\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"language\"\r\n\r\nen-US\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"description\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"transcript\"\r\n\r\n<string>\r\n-----011000010111000001101001--")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.nineninesix.ai/voices/clone")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["Authorization"] = 'Bearer <token>'
request.body = "-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"clip\"; filename=\"example-file\"\r\nContent-Type: application/octet-stream\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"name\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"language\"\r\n\r\nen-US\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"description\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"transcript\"\r\n\r\n<string>\r\n-----011000010111000001101001--"

response = http.request(request)
puts response.read_body

{
  "id": "5148a2db-5f7c-480c-8f7c-39c6414a4d5d",
  "is_owner": false,
  "is_public": true,
  "name": "Jessica",
  "description": "Polished, quick New York professional around thirty-five, warm underneath the hustle. Jessica makes a stressful thing feel manageable.",
  "gender": "feminine",
  "language": "en-US",
  "country": "US",
  "created_at": "2026-08-14T18:26:40.876Z",
  "preview_file_url": "<string>"
}

Authorizations

Authorization

string

header

required

Pass your API key as a Bearer token: Authorization: Bearer sk_996_....

Body

multipart/form-data

clip

file

required

Reference audio to clone from. WAV recommended; FLAC, OGG, MP3, and M4A also work. 1–300 s, under 20 MB. Only the first 20 s of speech (after silence trimming) is used.

name

string

required

A name for the cloned voice.

language

string

A well-formed BCP-47 language tag, e.g. en-US, en-GB, es-MX, pt-BR, nl-NL. Stored as metadata (used for listing and filtering); it doesn't change synthesis. The value is canonicalized on save (en-us → en-US, pt-br → pt-BR). Malformed tags (en_US, en-USA, english_, 123) are rejected with invalid_language (400).

Example:

"en-US"

description

string

A description of the voice.

transcript

string

The exact words spoken in the clip. With a transcript, the clone follows the speaker, including their pace, more closely. It must match the audio exactly, and it's ignored if the clip has 20 s or more of speech after silence trimming, so send a clip under 20 s when you use it. Not a Cartesia SDK field: pass it via extra_body (Python) or as an extra key with a type cast (TypeScript).

Response

The newly created voice.

string<uuid>

Example:

"5148a2db-5f7c-480c-8f7c-39c6414a4d5d"

is_owner

boolean

true if your org owns the voice (you cloned it).

Example:

false

is_public

boolean

true for shared library voices.

Example:

true

name

string

Example:

"Jessica"

description

string

Example:

"Polished, quick New York professional around thirty-five, warm underneath the hustle. Jessica makes a stressful thing feel manageable."

gender

enum<string>

Available options:

masculine,

feminine,

gender_neutral

Example:

"feminine"

language

string

BCP-47 dialect tag (e.g. en-US, nl-NL).

Example:

"en-US"

country

string

Country code.

Example:

"US"

created_at

string<date-time>

When the voice was created.

Example:

"2026-08-14T18:26:40.876Z"

preview_file_url

string

Only present when the request sends expand[]=preview_file_url. A signed, browser-playable URL of the voice's preview.