# ElevenLabs Eleven v4 Turbo API

ElevenLabs Eleven v4 Turbo: expressive multilingual speech with audio tags, voice selection and delivery controls.

Base URL: https://01router.com/api/v1
Model ID: elevenlabs-tts-v4-turbo
Documentation: https://01router.com/gateway/elevenlabs-tts-v4-turbo#api

## Quick start

Set API_KEY to your project key, then run a sample from your server. Replace example media URLs with your own public URLs.

```bash
export API_KEY="YOUR_API_KEY"
curl "https://01router.com/api/v1/generations" \
  -H "Authorization: Bearer $API_KEY" \
  -H "Content-Type: application/json" \
  --data-binary @- <<'JSON'
{
  "model": "elevenlabs-tts-v4-turbo",
  "input": {
    "prompt": "Welcome back. Let us get started.",
    "voice": "Rachel",
    "stability": 0.5,
    "similarity_boost": 0.75,
    "output_format": "mp3_44100_128",
    "apply_text_normalization": "auto"
  }
}
JSON
```

## Endpoints

| Method | Path | Authentication | Description |
| --- | --- | --- | --- |
| POST | /api/v1/generations | API key required | Create a generation (charges credits) |
| GET | /api/v1/generations/{id} | API key required | Get a generation; polls the provider while running |
| POST | /api/v1/generations/{id}/cancel | API key required | Cancel a running generation (credits refunded) |
| POST | /api/v1/quote | Public · no key | Price a request on every provider (no charge, no key needed) |
| GET | /api/v1/models/elevenlabs-tts-v4-turbo | Public · no key | Get one model |

## Authentication

Send your API key as a Bearer token. Requests are billed to the key owner's credits.

`Authorization: Bearer <API_KEY>`

## Input

Send JSON with Content-Type: application/json. Model parameters belong inside input; model, provider and callback_url are top-level fields.

| Name | Type | Required | Description |
| --- | --- | --- | --- |
| model | string | Yes | "elevenlabs-tts-v4-turbo" |
| provider | string | No | Pin a provider; omit to auto-route to the cheapest. One of: fal \| wavespeed \| openrouter |
| input | object | Yes | Model parameters, see the input fields below. |
| callback_url | string | No | Optional public HTTPS webhook URL. The final task result is signed and delivered here; polling remains available. |

### input

Required fields are marked explicitly. Other fields use the listed defaults when omitted.

| Name | Type | Required | Description | Default |
| --- | --- | --- | --- | --- |
| input.prompt | string | Yes | Text; maxLength: 5000 | — |
| input.voice | string | No | Voice | "Rachel" |
| input.stability | number | No | Stability; min: 0; max: 1 | 0.5 |
| input.similarity_boost | number | No | Voice similarity; min: 0; max: 1 | 0.75 |
| input.language_code | string | No | ISO 639-1, e.g. en or zh | — |
| input.seed | integer | No | Seed; min: 0; max: 4294967295 | — |
| input.output_format | string | No | Output format; options: ["mp3_22050_32","mp3_44100_32","mp3_44100_64","mp3_44100_96","mp3_44100_128","mp3_44100_192","pcm_8000","pcm_16000","pcm_22050","pcm_24000","pcm_44100","pcm_48000","ulaw_8000","alaw_8000","opus_48000_32","opus_48000_64","opus_48000_96","opus_48000_128","opus_48000_192"] | "mp3_44100_128" |
| input.apply_text_normalization | string | No | Text normalization; options: ["auto","on","off"] | "auto" |

Auto-routing chooses a provider that supports the request. Select a provider to see its input constraints and pinned request examples.

### Provider input schemas

```json
[
  {
    "provider": "fal",
    "params": [
      {
        "name": "prompt",
        "type": "text",
        "label": "Text",
        "required": true,
        "maxLength": 5000
      },
      {
        "name": "voice",
        "type": "string",
        "label": "Voice",
        "default": "Rachel"
      },
      {
        "name": "stability",
        "type": "number",
        "label": "Stability",
        "min": 0,
        "max": 1,
        "default": 0.5
      },
      {
        "name": "similarity_boost",
        "type": "number",
        "label": "Voice similarity",
        "min": 0,
        "max": 1,
        "default": 0.75
      },
      {
        "name": "language_code",
        "type": "string",
        "label": "Language code",
        "description": "ISO 639-1, e.g. en or zh"
      },
      {
        "name": "seed",
        "type": "integer",
        "label": "Seed",
        "min": 0,
        "max": 4294967295
      },
      {
        "name": "output_format",
        "type": "enum",
        "label": "Output format",
        "options": [
          "mp3_22050_32",
          "mp3_44100_32",
          "mp3_44100_64",
          "mp3_44100_96",
          "mp3_44100_128",
          "mp3_44100_192",
          "pcm_8000",
          "pcm_16000",
          "pcm_22050",
          "pcm_24000",
          "pcm_44100",
          "pcm_48000",
          "ulaw_8000",
          "alaw_8000",
          "opus_48000_32",
          "opus_48000_64",
          "opus_48000_96",
          "opus_48000_128",
          "opus_48000_192"
        ],
        "default": "mp3_44100_128"
      },
      {
        "name": "apply_text_normalization",
        "type": "enum",
        "label": "Text normalization",
        "options": [
          "auto",
          "on",
          "off"
        ],
        "default": "auto"
      }
    ]
  },
  {
    "provider": "wavespeed",
    "params": [
      {
        "name": "prompt",
        "type": "text",
        "label": "Text",
        "required": true,
        "maxLength": 5000
      },
      {
        "name": "voice",
        "type": "string",
        "label": "Voice",
        "default": "Alicia"
      },
      {
        "name": "stability",
        "type": "number",
        "label": "Stability",
        "min": 0,
        "max": 1,
        "default": 0.5
      },
      {
        "name": "similarity_boost",
        "type": "number",
        "label": "Voice similarity",
        "min": 0,
        "max": 1,
        "default": 0.75
      }
    ]
  },
  {
    "provider": "openrouter",
    "params": [
      {
        "name": "prompt",
        "type": "text",
        "label": "Text",
        "required": true,
        "maxLength": 5000
      },
      {
        "name": "voice",
        "type": "string",
        "label": "Voice",
        "default": "george",
        "options": [
          "george",
          "sarah",
          "adam",
          "alice",
          "bella",
          "bill",
          "brian",
          "callum",
          "charlie",
          "chris",
          "daniel",
          "eric",
          "harry",
          "jessica",
          "laura",
          "liam",
          "lily",
          "matilda",
          "river",
          "roger",
          "will"
        ]
      }
    ]
  }
]
```

## Output

Creating a task does not mean generation has finished. Keep its id, poll until succeeded or failed, then read outputs or error. Amounts below are illustrative; actual charges depend on the request.

| Name | Type | Required | Description |
| --- | --- | --- | --- |
| id | string | Yes | Generation ID. Use it to query or cancel this task. |
| object | string | Yes | generation |
| model | string | Yes | elevenlabs-tts-v4-turbo |
| type | string | Yes | audio |
| provider | string | Yes | Provider |
| status | string | Yes | queued → processing → succeeded / failed. Stop polling at either terminal state. |
| input | object | Yes | Model parameters, see the input fields below. |
| outputs | string[] | Yes | Result URLs. Empty while processing; read after succeeded and save the files promptly. |
| error | string \| null | Yes | Failure reason, or null when no failure is reported. |
| credits | number | Yes | Credits charged for this request. |
| price_usd | number | Yes | Request price in USD. |
| created_at | string | Yes | Creation time in ISO 8601 format. |
| completed_at | string \| null | Yes | Completion time in ISO 8601 format; null before completion. |

### Task submitted

```json
{
  "id": "gen_example",
  "object": "generation",
  "model": "elevenlabs-tts-v4-turbo",
  "type": "audio",
  "provider": "fal",
  "status": "processing",
  "input": {
    "prompt": "Welcome back. Let us get started.",
    "voice": "Rachel",
    "stability": 0.5,
    "similarity_boost": 0.75,
    "output_format": "mp3_44100_128",
    "apply_text_normalization": "auto"
  },
  "outputs": [],
  "error": null,
  "credits": 0,
  "price_usd": 0,
  "created_at": "2026-10-25T08:00:00.000Z",
  "completed_at": null
}
```

### Task completed

```json
{
  "id": "gen_example",
  "object": "generation",
  "model": "elevenlabs-tts-v4-turbo",
  "type": "audio",
  "provider": "fal",
  "status": "succeeded",
  "input": {
    "prompt": "Welcome back. Let us get started.",
    "voice": "Rachel",
    "stability": 0.5,
    "similarity_boost": 0.75,
    "output_format": "mp3_44100_128",
    "apply_text_normalization": "auto"
  },
  "outputs": [
    "https://example.com/output.wav"
  ],
  "error": null,
  "credits": 0,
  "price_usd": 0,
  "created_at": "2026-10-25T08:00:00.000Z",
  "completed_at": "2026-10-25T08:01:00.000Z"
}
```

## Get the result

Poll every few seconds until status is succeeded or failed. Output URLs are provider-hosted and may expire — download them promptly. Or pass callback_url to get the result pushed.

```bash
curl "https://01router.com/api/v1/generations/GENERATION_ID" -H "Authorization: Bearer $API_KEY"
```

## Cancel a task

Cancellation depends on provider support and task state. A confirmed cancellation returns status: failed and error: Canceled by user. Unsupported or completed tasks return 409 not_cancelable.

```bash
curl -X POST "https://01router.com/api/v1/generations/GENERATION_ID/cancel" -H "Authorization: Bearer $API_KEY"
```

## Quote

Same body as creating a generation. Returns every available provider sorted by price, plus the ones that cannot serve the request and why.

```bash
curl "https://01router.com/api/v1/quote" -H "Content-Type: application/json" --data-binary @- <<'JSON'
{
  "model": "elevenlabs-tts-v4-turbo",
  "input": {
    "prompt": "Welcome back. Let us get started.",
    "voice": "Rachel",
    "stability": 0.5,
    "similarity_boost": 0.75,
    "output_format": "mp3_44100_128",
    "apply_text_normalization": "auto"
  }
}
JSON
```

## Callbacks

Optional public HTTPS webhook URL. The final task result is signed and delivered here; polling remains available.

See https://01router.com/docs/callback for signature verification.

## Errors

Check the HTTP status and error.message. Fix the request before retrying validation or authentication errors. A failed generation is reported in status and error on the task itself.

```json
{
  "error": {
    "message": "Invalid or missing API key",
    "code": "unauthorized"
  }
}
```

HTTP 400: invalid request; 401: unauthorized; 402: insufficient credits; 404: not found; 409: not cancelable; 429: rate/concurrency/quota limit; 5xx: upstream/server error.

Full API reference: https://01router.com/docs/errors