Voice cloning

Create a voice your organization owns in three ways: instant clone from a single clip, pro clone from a multi-file dataset, or localization of an existing voice into another language. A cloned voice is used in TTS requests like any other voice. Asynchronous operations return a job_id; poll GET /jobs/:id until the job settles.

Instant clone

POST /voices/clone accepts the audio in one of three forms:

multipart/form-data — one file field plus the text fields below.
Raw body — Content-Type: audio/* or application/octet-stream; text fields go in query params.
JSON — {"blob_id": "..."} referencing audio already stored with your organization.

Send exactly one clip per request; zero or several return 400 missing_clip. Use 10–30 seconds of clean speech — 10 seconds is the working minimum. Caps: 25 MB per clip (413) and 250 MB of stored audio per organization (413 blob_quota_exceeded).

Field	Type	Constraint	Default
`name`	string	Required — 400 `missing_name` without it	—
`mode`	string	`stability` or `similarity`	`similarity`
`language`	string	ISO code	none
`transcript`	string	Transcript of the clip, ≤20,000 characters	none
`model_id`	string	Model to prepare the voice for	`omnivoice`

import requests

resp = requests.post(
    "https://api.withhopper.com/voices/clone",
    headers={"Authorization": "Bearer sk_hopper_..."},
    files={"file": open("clip.wav", "rb")},
    data={"name": "Support agent", "language": "en"},
)
body = resp.json()
# 201 -> body is the Voice, ready now; 202 -> {"job_id", "voice_id", "status": "queued"}

import { openAsBlob } from "node:fs";

const form = new FormData();
form.append("file", await openAsBlob("clip.wav"), "clip.wav");
form.append("name", "Support agent");
form.append("language", "en");

const resp = await fetch("https://api.withhopper.com/voices/clone", {
  method: "POST",
  headers: { Authorization: "Bearer sk_hopper_..." },
  body: form,
});
const body = await resp.json();
// 201 -> body is the Voice, ready now; 202 -> {"job_id", "voice_id", "status": "queued"}

curl https://api.withhopper.com/voices/clone \
  -H "Authorization: Bearer sk_hopper_..." \
  -F "file=@clip.wav" \
  -F "name=Support agent" \
  -F "language=en"

Two success shapes:

201 — the clone ran synchronously; the body is the finished Voice, usable in TTS immediately.
202 — {"job_id": "...", "voice_id": "...", "status": "queued"}. The voice row exists now under the returned voice_id; its profile attaches when the job succeeds.

Pro clone

POST /voices/clone/pro builds a higher-fidelity voice from a dataset. Provide 10+ minutes of audio across files, 25 MB per file. Input forms: multipart with multiple file fields, a raw audio body, or JSON {"blob_ids": ["..."]}. name is required. There is no mode field. Pro clones never complete synchronously. The endpoint always returns 202 {"job_id": "...", "status": "..."}.

Localize

POST /voices/:id/localize derives a new voice in another language. Body: {"target_language": "..."} (required — 400 without it) plus optional model_id. Returns 202 {"job_id": "...", "status": "..."}. The result is a new voice your organization owns, with source: "localized" and parent_voice_id pointing at the original. Featured platform voices can be localized; the original is untouched.

Polling jobs

GET /jobs/:id returns the state of any clone or localize job in your organization; unknown ids return 404.

Field	Values
`id`	job id
`kind`	`instant_clone`, `pro_clone`, `localize`
`status`	`queued`, `running`, `succeeded`, `failed`
`created_at`, `updated_at`	timestamps
`result`	on success: `{"voice_id": "...", "profile": {model_id, profile_kind, profile_version, status}}`
`error`	on failure, e.g. `model_offline` when no upstream is configured

Poll until the status leaves queued/running:

import time, requests

headers = {"Authorization": "Bearer sk_hopper_..."}
url = f"https://api.withhopper.com/jobs/{job_id}"

job = requests.get(url, headers=headers).json()
while job["status"] in ("queued", "running"):
    time.sleep(2)
    job = requests.get(url, headers=headers).json()

if job["status"] == "succeeded":
    voice_id = job["result"]["voice_id"]  # ready for /tts/bytes

Get started

LLM

Text to Speech

Speech to Text

Platform

Instant clone

Pro clone

Localize

Polling jobs

​Instant clone

​Pro clone

​Localize

​Polling jobs

Instant clone

Pro clone

Localize

Polling jobs