Custom voices: request a professional voice clone

A professional voice clone is a voice we build for your workspace from recordings of one real person. You upload 30 minutes to 2 hours of them talking, plus a short clip of them agreeing to it, and our team builds a voice your agents can use on calls. It’s worth it when none of the catalogue voices sounds like you:

Your brand already has a voice, such as the person in your ads or the support lead your customers know by name.
You need an accent the catalogue doesn’t have, such as Australian English.
You want a voice that is at home in your languages: Gujarati, Tamil, Telugu, or the Hindi and English mix your customers actually speak.

If a catalogue voice already sounds right, use it. It’s ready today, and nobody has to spend an afternoon talking to a microphone.

Who can request one, and what it costs

Any workspace can send a request, from the console or the API. In the console, sign in with your work email first; the page stays locked while you’re only looking around. A workspace can have five requests open at a time. Requests that are ready or not accepted don’t count towards that. Custom voices come with a volume commitment on our Enterprise plan. See Billing & tiers. Sending a request doesn’t charge your wallet: our team gets in touch to agree pricing with you before training starts.

Before you record

We build the voice from these recordings, so how they sound is how your agent will sound.

The speaker

One speaker only. Every file must be the same person. If someone else talks during a session, for example to prompt the speaker with questions, cut them out before you upload.
Speak the way the agent should sound on calls: conversational, at a natural pace, as if talking to a customer. A script read in a newsreader voice gets you a newsreader.
Use the languages, and the mix, you want the voice to speak. If the speaker talks to customers in Hinglish, record Hinglish.

The room and the microphone

Record in a quiet room.
Use the same microphone, at the same distance from the speaker, for every session.
Send the audio as it was recorded: no music, no voices in the background, no heavy noise reduction and no effects. Trimming silences and false starts is fine.

How much, and in what format

Record 30 minutes at least and 2 hours at most. We add up the length of all your recordings, and a request can’t be sent with less than 30 minutes or more than 2 hours. Trim long silences, so that the 30 minutes is the speaker talking.
Split long sessions into several files if you like. Each file can be up to 1 GB, with 3 GB in total.
WAV or FLAC at 44.1 kHz or higher is best. MP3 at 192 kbps or better is fine. We also accept M4A, AAC, MP4, OGG, Opus and WebM.

We only build a voice with the speaker’s permission, and every request carries it twice. First, whoever sends the request confirms that the speaker has agreed, in writing, to us building a voice from their recordings. You give your name and your relationship to the speaker: yourself, an employee, a contractor or someone else. Keep the written agreement where you can find it. Second, the speaker records a short consent statement in their own voice. The console shows the sentence to read and can record it in your browser, or you can upload a recording of them reading it. The sentence is:

My name is speaker’s name. I agree to Mirai creating a synthetic version of my voice for your company. Today is today’s date.

Never upload a voice from another platform, a celebrity’s voice, or the voice of anyone who hasn’t agreed. We don’t accept a request without the speaker’s consent.

The speaker can withdraw consent at any time. Delete the request, whatever its status, and we delete its recordings and its consent clip. If we’ve already built the voice, we take it down too. We keep the request’s details, without any audio, in our records for audit. A voice is personal data. Make sure your agreement with the speaker says how the voice will be used on your calls.

Request a voice in the console

Start a request

Open Custom voices in the sidebar, under Workspace, and click Request a voice clone.

Tell us about the voice

Give the voice a name of up to 60 characters; this is how it appears in your list. Add the speaker’s name and the languages the voice should speak: Hindi, English, Gujarati, Tamil or Telugu. Gender, accent (such as Australian English) and notes for our team are optional.

Confirm consent

Tick the consent statement, and add your name and your relationship to the speaker. Then have the speaker read the consent sentence, recorded in the browser or uploaded as a file.

Upload the recordings

Add the recording files. You need between 30 minutes and 2 hours in total. Until you send it, the request is a draft, so you can come back and add more later.

Submit

Send the request. If something is missing, the console says what, for example “Add at least 30 minutes of recordings. You have 24 minutes so far.”

What each status means

There’s no fixed turnaround. Our team reviews the recordings and updates the status as the request moves along. Anything we need you to know comes as a note on the request.

Console	`status`	What it means
Draft	`draft`	You’re still putting it together. You can edit it and add or remove recordings.
Sent	`submitted`	We have it, and it’s waiting for our team. You can’t edit it now.
In review	`in_review`	Our team is reviewing the recordings. We get in touch about pricing before training starts.
Training	`training`	We’re building the voice.
Ready	`ready`	The voice is built. The request shows its `voice_id`.
Needs changes	`needs_changes`	We need something from you, and the note says what. Edit the request or its recordings, then send it again.
Not accepted	`rejected`	We can’t build a voice from this request. The note says why.

When a request is ready, our team gets in touch to switch your agents to the new voice. Its voice_id is on the request so you can tell it apart from the catalogue voices.

Request a voice with the API

Base URL https://sandbox.voice.miraiminds.co. All endpoints require Authorization: Bearer sk_live_…, and a request belongs to the workspace of the key that created it.

export MIRAI_API_BASE="https://sandbox.voice.miraiminds.co"
export MIRAI_API_KEY="sk_live_YOUR_API_KEY"

Method	Path	What it does
`POST`	`/v2/voice-clones`	Create a request. It starts as a `draft`.
`GET`	`/v2/voice-clones`	List your workspace’s requests, newest first.
`GET`	`/v2/voice-clones/{id}`	Get one request, with its files.
`PATCH`	`/v2/voice-clones/{id}`	Change any of the fields you sent on create. Draft or needs changes only.
`DELETE`	`/v2/voice-clones/{id}`	Delete the request and all its audio, at any status.
`POST`	`/v2/voice-clones/{id}/files`	Register a recording or the consent clip before uploading it.
`PUT`	`/v2/voice-clones/{id}/files/{file_id}/chunks/{index}`	Upload one chunk of a file.
`POST`	`/v2/voice-clones/{id}/files/{file_id}/complete`	Finish a file once every chunk is in.
`DELETE`	`/v2/voice-clones/{id}/files/{file_id}`	Remove a file. Draft or needs changes only.
`POST`	`/v2/voice-clones/{id}/submit`	Send the request to our team.

Files are large, so they go up in chunks of 16 MiB (16,777,216 bytes): you register the file, upload its chunks, mark it complete, and submit the request when everything is in.

1. Create a request

curl --fail-with-body -X POST "$MIRAI_API_BASE/v2/voice-clones" \
  -H "Authorization: Bearer $MIRAI_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "Priya (support)",
    "speaker_name": "Priya Sharma",
    "languages": ["hi", "en"],
    "gender": "female",
    "notes": "Warm and unhurried. She mixes Hindi and English on calls.",
    "consent": {
      "attested": true,
      "attested_by": "Rahul Mehta",
      "relationship": "employee"
    }
  }'

Field	Type	Description
`name`	string	Required. The voice’s display name, 1 to 60 characters.
`speaker_name`	string	Required. The person whose voice it is, 1 to 100 characters.
`languages`	array	Required. At least one of `hi`, `en`, `gu`, `ta` and `te`.
`gender`	string	Optional. `female`, `male` or `other`.
`accent`	string	Optional, up to 100 characters, such as `Australian English`.
`notes`	string	Optional notes for our team, up to 2,000 characters.
`consent.attested`	boolean	`true` confirms the speaker agreed in writing. It must be `true` before you can submit.
`consent.attested_by`	string	Your name, 1 to 100 characters.
`consent.relationship`	string	The speaker is `self`, an `employee`, a `contractor` or `other`.

The response is 201 Created. attested_at is the time we recorded your confirmation.

{
  "id": "vcl_01K8C2W7H4M9P3R6T1V5X8Z0QA",
  "object": "voice_clone",
  "status": "draft",
  "name": "Priya (support)",
  "speaker_name": "Priya Sharma",
  "languages": ["hi", "en"],
  "gender": "female",
  "accent": "",
  "notes": "Warm and unhurried. She mixes Hindi and English on calls.",
  "consent": {
    "attested": true,
    "attested_by": "Rahul Mehta",
    "relationship": "employee",
    "attested_at": "2026-10-21T17:10:00Z"
  },
  "sample_seconds": 0,
  "min_sample_seconds": 1800,
  "max_sample_seconds": 7200,
  "files": [],
  "voice_id": null,
  "status_note": "",
  "created_at": "2026-10-21T17:10:00Z",
  "updated_at": "2026-10-21T17:10:00Z",
  "submitted_at": null
}

export MIRAI_VCL_ID="vcl_01K8C2W7H4M9P3R6T1V5X8Z0QA"

2. Register a recording

Tell us about the file before you send it. bytes must be the file’s exact size. duration_seconds is its length; for a WAV file we read the length from the file itself when you finish it, and for other formats we use the number you send. ffprobe -v error -show_entries format=duration -of csv=p=0 session-1.mp3 prints it.

FILE=session-1.wav
BYTES=$(wc -c < "$FILE" | tr -d ' ')

curl --fail-with-body -X POST "$MIRAI_API_BASE/v2/voice-clones/$MIRAI_VCL_ID/files" \
  -H "Authorization: Bearer $MIRAI_API_KEY" \
  -H "Content-Type: application/json" \
  -d "{ \"kind\": \"sample\", \"filename\": \"$FILE\", \"bytes\": $BYTES,
        \"content_type\": \"audio/wav\", \"duration_seconds\": 1201.4 }"

kind is sample for a recording and consent for the consent clip. The response is 201 Created, and chunks says how many pieces to send:

{
  "id": "vcf_01K8C2X3B6D9F2H5K8M1P4R7T0",
  "object": "voice_clone_file",
  "kind": "sample",
  "filename": "session-1.wav",
  "content_type": "audio/wav",
  "bytes": 211812352,
  "received_bytes": 0,
  "chunk_bytes": 16777216,
  "chunks": 13,
  "received_chunks": [],
  "duration_seconds": 1201.4,
  "duration_source": "client",
  "sha256": "",
  "status": "uploading",
  "created_at": "2026-10-21T17:12:30Z"
}

export MIRAI_VCF_ID="vcf_01K8C2X3B6D9F2H5K8M1P4R7T0"

3. Upload the chunks

Send chunk 0 to chunks - 1 as raw bytes. Every chunk is exactly chunk_bytes long except the last, which is whatever is left. Chunks can go in any order, and sending one again overwrites it.

CHUNKS=13   # "chunks" from step 2
for i in $(seq 0 $((CHUNKS - 1))); do
  dd if="$FILE" bs=16777216 skip="$i" count=1 2>/dev/null |
  curl --fail-with-body -X PUT \
    "$MIRAI_API_BASE/v2/voice-clones/$MIRAI_VCL_ID/files/$MIRAI_VCF_ID/chunks/$i" \
    -H "Authorization: Bearer $MIRAI_API_KEY" \
    -H "Content-Type: application/octet-stream" \
    --data-binary @-
done

Each PUT answers 200 with the file, and received_chunks lists the chunks we have so far.

4. Finish the file

curl --fail-with-body -X POST \
  "$MIRAI_API_BASE/v2/voice-clones/$MIRAI_VCL_ID/files/$MIRAI_VCF_ID/complete" \
  -H "Authorization: Bearer $MIRAI_API_KEY"

We put the chunks together into one file. The response is the file with status complete and its sha256. For a WAV file, duration_seconds now comes from the file and duration_source is header. If any chunk is missing, you get 409 incomplete naming the missing chunks; send those and call complete again. Repeat steps 2 to 4 for each recording. The request’s sample_seconds adds up the length of every finished recording. Upload the speaker reading the consent sentence the same way, with "kind": "consent". A request holds one consent clip, up to 50 MB. To replace it, delete the old one first.

FILE=consent.wav
BYTES=$(wc -c < "$FILE" | tr -d ' ')

curl --fail-with-body -X POST "$MIRAI_API_BASE/v2/voice-clones/$MIRAI_VCL_ID/files" \
  -H "Authorization: Bearer $MIRAI_API_KEY" \
  -H "Content-Type: application/json" \
  -d "{ \"kind\": \"consent\", \"filename\": \"$FILE\", \"bytes\": $BYTES,
        \"content_type\": \"audio/wav\", \"duration_seconds\": 10 }"

Then upload its chunks and finish it as in steps 3 and 4.

6. Submit

curl --fail-with-body -X POST "$MIRAI_API_BASE/v2/voice-clones/$MIRAI_VCL_ID/submit" \
  -H "Authorization: Bearer $MIRAI_API_KEY"

The response is the request with status submitted. To submit, the request needs consent.attested set to true, one finished consent clip, between 1,800 and 7,200 seconds of finished recordings, and no file still uploading. If something is missing, you get 422 not_ready with a message that says what:

422 Unprocessable Entity

{
  "error": {
    "code": "not_ready",
    "message": "Add at least 30 minutes of recordings. You have 24 minutes so far."
  }
}

Resume an upload

If an upload stops partway, get the request and look at the file in files:

curl --fail-with-body "$MIRAI_API_BASE/v2/voice-clones/$MIRAI_VCL_ID" \
  -H "Authorization: Bearer $MIRAI_API_KEY"

received_chunks lists the chunks we already have. Send the others, then finish the file. This Python function does both, and you can run it again after any failure:

import os, httpx

base = os.environ["MIRAI_API_BASE"]
auth = {"Authorization": f"Bearer {os.environ['MIRAI_API_KEY']}"}

def upload(vcl_id: str, file_id: str, local_path: str) -> dict:
    vc = httpx.get(f"{base}/v2/voice-clones/{vcl_id}", headers=auth, timeout=30).raise_for_status().json()
    f = next(x for x in vc["files"] if x["id"] == file_id)
    url = f"{base}/v2/voice-clones/{vcl_id}/files/{file_id}"
    have = set(f["received_chunks"])
    with open(local_path, "rb") as src:
        for i in range(f["chunks"]):
            if i in have:
                continue
            src.seek(i * f["chunk_bytes"])
            httpx.put(f"{url}/chunks/{i}", content=src.read(f["chunk_bytes"]),
                      headers={**auth, "Content-Type": "application/octet-stream"},
                      timeout=300).raise_for_status()
    return httpx.post(f"{url}/complete", headers=auth, timeout=300).raise_for_status().json()

Follow the status

GET /v2/voice-clones/{id} returns the request with its status and our status_note. GET /v2/voice-clones lists every request in your workspace as {"object": "list", "data": [...]}, newest first. The status changes when our team moves the request along, so there’s no need to check often. When it is ready, voice_id names your new voice, and we’ll help you move your agents onto it.

Change or delete a request

While a request is draft or needs_changes, PATCH /v2/voice-clones/{id} changes any of the fields from step 1; at any other status it answers 409 not_editable. Adding and removing files works in those two statuses only. DELETE /v2/voice-clones/{id}/files/{file_id} answers {"id": "vcf_…", "object": "voice_clone_file", "deleted": true}. DELETE /v2/voice-clones/{id} works at any status. It deletes every recording and the consent clip, and answers:

{ "id": "vcl_01K8C2W7H4M9P3R6T1V5X8Z0QA", "object": "voice_clone", "deleted": true }

Limits

Limit	Value
Recordings per request	30 minutes to 2 hours in total
File size	1 GB per file, 3 GB per request
Files per request	60
Consent clip	One per request, up to 50 MB
Chunk size	16 MiB (16,777,216 bytes); the last chunk is the remainder
Open requests per workspace	5 (ready and not accepted requests don’t count)
Languages	`hi`, `en`, `gu`, `ta`, `te`
File types	`.wav`, `.flac`, `.mp3`, `.m4a`, `.aac`, `.mp4`, `.ogg`, `.opus`, `.webm`

Errors

Errors use the standard envelope.

Status	`code`	Meaning
`400`	`invalid_request`	A field is missing or out of range. The message names it.
`400`	`bad_chunk`	A chunk is the wrong size. Every chunk but the last must be exactly `chunk_bytes`.
`404`	`not_found`	No such request or file in your workspace.
`409`	`limit_reached`	Your workspace already has five open requests, or the request already has 60 files, 3 GB of audio or a consent clip.
`409`	`not_editable`	The request has been sent, so it can’t be changed. You can still delete it.
`409`	`incomplete`	You finished a file with chunks still missing. `error.missing_chunks` lists them.
`409`	`file_complete`	That file is already finished, so it takes no more chunks.
`409`	`assembling`	We’re joining that file’s chunks right now. Wait a moment, then check the file.
`413`	`file_too_large`	The file is over 1 GB, or the consent clip is over 50 MB.
`415`	`unsupported_file_type`	We can’t take that file type. Send WAV, FLAC, MP3, M4A, AAC, MP4, OGG, Opus or WebM.
`422`	`not_ready`	The request isn’t ready to send. The message says what’s missing.
`507`	`insufficient_storage`	We can’t take more audio right now. Try again later.

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Reference

Custom voices: request a professional voice clone

Who can request one, and what it costs

Before you record

The speaker

The room and the microphone

How much, and in what format

Request a voice in the console

What each status means

Request a voice with the API

1. Create a request

2. Register a recording

3. Upload the chunks

4. Finish the file

6. Submit

Resume an upload

Follow the status

Change or delete a request

Limits

Errors

​Who can request one, and what it costs

​Before you record

​The speaker

​The room and the microphone

​How much, and in what format

​Consent

​Request a voice in the console

​What each status means

​Request a voice with the API

​1. Create a request

​2. Register a recording

​3. Upload the chunks

​4. Finish the file

​5. Add the consent clip

​6. Submit

​Resume an upload

​Follow the status

​Change or delete a request

​Limits

​Errors

Who can request one, and what it costs

Before you record

The speaker

The room and the microphone

How much, and in what format

Consent

Request a voice in the console

What each status means

Request a voice with the API

1. Create a request

2. Register a recording

3. Upload the chunks

4. Finish the file

5. Add the consent clip

6. Submit

Resume an upload

Follow the status

Change or delete a request

Limits

Errors