---
title: Eleven Flash v2.5 | Runware Docs
url: https://runware.ai/docs/models/elevenlabs-flash-v2-5
description: Ultra low latency multilingual text to speech model
---
# Eleven Flash v2.5

Eleven Flash v2.5 is a real time text to speech model for voice agents and interactive apps. It delivers natural speech in about 75 ms latency across 32 languages. Use it for low latency conversational AI, games, live tools, and large scale TTS workloads.

- **ID**: `elevenlabs:24@1`
- **Status**: live
- **Creator**: ElevenLabs
- **Release Date**: December 19, 2024
- **Capabilities**: Text to Audio

## Request Parameters

**API Options**

Platform-level options for task execution and delivery.

### [taskType](https://runware.ai/docs/models/elevenlabs-flash-v2-5#request-tasktype)

- **Type**: `string`
- **Required**: true
- **Value**: `audioInference`

Identifier for the type of task being performed

### [taskUUID](https://runware.ai/docs/models/elevenlabs-flash-v2-5#request-taskuuid)

- **Type**: `string`
- **Required**: true
- **Format**: `UUID v4`

UUID v4 identifier for tracking tasks and matching async responses. Must be unique per task.

### [outputType](https://runware.ai/docs/models/elevenlabs-flash-v2-5#request-outputtype)

- **Type**: `string`
- **Default**: `URL`

Audio output type.

**Allowed values**: `URL` `base64Data` `dataURI`

### [outputFormat](https://runware.ai/docs/models/elevenlabs-flash-v2-5#request-outputformat)

- **Type**: `string`
- **Default**: `MP3`

Specifies the file format of the generated output. The available values depend on the task type and the specific model's capabilities.

- \`MP3\`: Compressed audio, smaller file size.
- \`WAV\`: Uncompressed, high-quality audio.
- \`FLAC\`: Lossless compression.
- \`OGG\`: Open-source compressed audio format (Vorbis codec).

**Allowed values**: `MP3` `WAV` `FLAC` `OGG`

### [audioSettings](https://runware.ai/docs/models/elevenlabs-flash-v2-5#request-audiosettings)

- **Path**: `audioSettings.bitrate`
- **Type**: `object (3 properties)`

Audio encoding settings for controlling the bitrate, number of channels, and sample rate of the generated audio. Only applicable for lossy output formats (`MP3` and `OGG`). When using lossless formats (`WAV` or `FLAC`), this parameter must not be provided.

The available sample rates and valid bitrate ranges depend on the output format. For `OGG`, bitrate limits also vary by the number of channels.

**MP3 bitrate limits**:

Bitrate limits for MP3 are the same regardless of mono or stereo.

| Sample Rate | Min Bitrate | Max Bitrate |
| --- | --- | --- |
| 8,000 Hz | 8 kbps | 64 kbps |
| 11,025 Hz | 8 kbps | 64 kbps |
| 12,000 Hz | 8 kbps | 64 kbps |
| 16,000 Hz | 8 kbps | 160 kbps |
| 22,050 Hz | 8 kbps | 160 kbps |
| 24,000 Hz | 8 kbps | 160 kbps |
| 32,000 Hz | 32 kbps | 320 kbps |
| 44,100 Hz | 32 kbps | 320 kbps |
| 48,000 Hz | 32 kbps | 320 kbps |

**OGG bitrate limits — Mono (1 channel)**:

| Sample Rate | Min Bitrate | Max Bitrate |
| --- | --- | --- |
| 8,000 Hz | 8 kbps | 40 kbps |
| 12,000 Hz | 16 kbps | 48 kbps |
| 16,000 Hz | 16 kbps | 96 kbps |
| 24,000 Hz | 16 kbps | 80 kbps |
| 48,000 Hz | 32 kbps | 224 kbps |

**OGG bitrate limits — Stereo (2 channels)**:

| Sample Rate | Min Bitrate | Max Bitrate |
| --- | --- | --- |
| 8,000 Hz | 16 kbps | 80 kbps |
| 12,000 Hz | 16 kbps | 96 kbps |
| 16,000 Hz | 24 kbps | 192 kbps |
| 24,000 Hz | 32 kbps | 160 kbps |
| 48,000 Hz | 48 kbps | 256 kbps |

> [!NOTE]
> **Lossless formats**: When `outputFormat` is set to `WAV` or `FLAC`, the `audioSettings` parameter is not available since these formats produce uncompressed or lossless audio with no configurable encoding settings.

#### [bitrate](https://runware.ai/docs/models/elevenlabs-flash-v2-5#request-audiosettings-bitrate)

- **Path**: `audioSettings.bitrate`
- **Type**: `integer`
- **Min**: `8`

Audio bitrate in kbps.

#### [channels](https://runware.ai/docs/models/elevenlabs-flash-v2-5#request-audiosettings-channels)

- **Path**: `audioSettings.channels`
- **Type**: `integer`
- **Default**: `2`

Number of audio channels. 1 for mono, 2 for stereo.

**Allowed values**: `1` `2`

#### [sampleRate](https://runware.ai/docs/models/elevenlabs-flash-v2-5#request-audiosettings-samplerate)

- **Path**: `audioSettings.sampleRate`
- **Type**: `integer`

Audio sample rate in Hz.

### [webhookURL](https://runware.ai/docs/models/elevenlabs-flash-v2-5#request-webhookurl)

- **Type**: `string`
- **Format**: `URI`

Specifies a webhook URL where JSON responses will be sent via HTTP POST when generation tasks complete. For batch requests with multiple results, each completed item triggers a separate webhook call as it becomes available.

**Learn more** (1 resource):

- [Webhooks](https://runware.ai/docs/platform/webhooks) (platform)

### [deliveryMethod](https://runware.ai/docs/models/elevenlabs-flash-v2-5#request-deliverymethod)

- **Type**: `string`
- **Default**: `sync`

Determines how the API delivers task results.

**Allowed values**:

- `sync` Returns complete results directly in the API response.
- `async` Returns an immediate acknowledgment with the task UUID. Poll for results using getResponse.

**Learn more** (1 resource):

- [Task Polling](https://runware.ai/docs/platform/task-polling) (platform)

### [uploadEndpoint](https://runware.ai/docs/models/elevenlabs-flash-v2-5#request-uploadendpoint)

- **Type**: `string`
- **Format**: `URI`

Specifies a URL where the generated content will be automatically uploaded using the HTTP PUT method. The raw binary data of the media file is sent directly as the request body. For secure uploads to cloud storage, use presigned URLs that include temporary authentication credentials.

**Common use cases:**

- **Cloud storage**: Upload directly to S3 buckets, Google Cloud Storage, or Azure Blob Storage using presigned URLs.
- **CDN integration**: Upload to content delivery networks for immediate distribution.

```text
// S3 presigned URL for secure upload
https://your-bucket.s3.amazonaws.com/generated/content.mp4?X-Amz-Signature=abc123&X-Amz-Expires=3600

// Google Cloud Storage presigned URL
https://storage.googleapis.com/your-bucket/content.jpg?X-Goog-Signature=xyz789

// Custom storage endpoint
https://storage.example.com/uploads/generated-image.jpg
```

The content data will be sent as the request body to the specified URL when generation is complete.

### [ttl](https://runware.ai/docs/models/elevenlabs-flash-v2-5#request-ttl)

- **Type**: `integer`
- **Min**: `60`

Time-to-live (TTL) in seconds for generated content. Only applies when `outputType` is `URL`.

### [includeCost](https://runware.ai/docs/models/elevenlabs-flash-v2-5#request-includecost)

- **Type**: `boolean`
- **Default**: `false`

Include task cost in the response.

### [numberResults](https://runware.ai/docs/models/elevenlabs-flash-v2-5#request-numberresults)

- **Type**: `integer`
- **Min**: `1`
- **Max**: `4`
- **Default**: `1`

Number of results to generate. Each result uses a different seed, producing variations of the same parameters.

**Generation Parameters**

Core parameters for controlling the generated content.

### [model](https://runware.ai/docs/models/elevenlabs-flash-v2-5#request-model)

- **Type**: `string`
- **Required**: true
- **Value**: `elevenlabs:24@1`

Identifier of the model to use for generation.

**Learn more** (3 resources):

- [Text To Image: Model Selection The Foundation Of Generation](https://runware.ai/docs/guides/text-to-image#model-selection-the-foundation-of-generation) (guide)
- [Image Inpainting: Model Specialized Inpainting Models](https://runware.ai/docs/guides/image-inpainting#model-specialized-inpainting-models) (guide)
- [Image Outpainting: Other Critical Parameters](https://runware.ai/docs/guides/image-outpainting#other-critical-parameters) (guide)

### [seed](https://runware.ai/docs/models/elevenlabs-flash-v2-5#request-seed)

- **Type**: `integer`
- **Min**: `0`
- **Max**: `4294967295`

Random seed for reproducible generation. When not provided, a random seed is generated in the unsigned 32-bit range.

### [speech](https://runware.ai/docs/models/elevenlabs-flash-v2-5#request-speech)

- **Path**: `speech.text`
- **Type**: `object (2 properties)`
- **Required**: true

Settings for speech generation.

#### [text](https://runware.ai/docs/models/elevenlabs-flash-v2-5#request-speech-text)

- **Path**: `speech.text`
- **Type**: `string`
- **Max**: `40000`

Text to convert to speech.

#### [language](https://runware.ai/docs/models/elevenlabs-flash-v2-5#request-speech-language)

- **Path**: `speech.language`
- **Type**: `string`
- **Min**: `1`

Language code for speech generation.

**Allowed values**: `en` `ja` `zh` `de` `hi` `fr` `ko` `pt` `it` `es` `ru` `id` `nl` `tr` `fil` `pl` `sv` `bg` `ro` `ar` `cs` `el` `fi` `hr` `ms` `sk` `da` `ta` `uk` `hu` `no` `vi`

**Provider Settings**

Parameters specific to this model provider. These must be nested inside the \`providerSettings.elevenlabs\` object.

### [textToSpeech](https://runware.ai/docs/models/elevenlabs-flash-v2-5#request-providersettings-elevenlabs-texttospeech)

- **Path**: `providerSettings.elevenlabs.textToSpeech`
- **Type**: `object (9 properties)`

Provider-specific settings for ElevenLabs text-to-speech generation.

#### [voiceSettings](https://runware.ai/docs/models/elevenlabs-flash-v2-5#request-providersettings-elevenlabs-texttospeech-voicesettings)

- **Path**: `providerSettings.elevenlabs.textToSpeech.voiceSettings`
- **Type**: `object (4 properties)`

Voice settings overriding stored settings for the given voice. Applied only on the given request.

##### [stability](https://runware.ai/docs/models/elevenlabs-flash-v2-5#request-providersettings-elevenlabs-texttospeech-voicesettings-stability)

- **Path**: `providerSettings.elevenlabs.textToSpeech.voiceSettings.stability`
- **Type**: `float`
- **Min**: `0`
- **Max**: `1`

Controls voice stability and randomness between each generation. Lower values introduce broader emotional range, higher values produce a more consistent tone.

##### [useSpeakerBoost](https://runware.ai/docs/models/elevenlabs-flash-v2-5#request-providersettings-elevenlabs-texttospeech-voicesettings-usespeakerboost)

- **Path**: `providerSettings.elevenlabs.textToSpeech.voiceSettings.useSpeakerBoost`
- **Type**: `boolean`

Boosts similarity to the original speaker at a slight increase in computational load and latency.

##### [similarityBoost](https://runware.ai/docs/models/elevenlabs-flash-v2-5#request-providersettings-elevenlabs-texttospeech-voicesettings-similarityboost)

- **Path**: `providerSettings.elevenlabs.textToSpeech.voiceSettings.similarityBoost`
- **Type**: `float`
- **Min**: `0`
- **Max**: `1`

Controls how closely the AI adheres to the original voice when attempting to replicate it.

##### [style](https://runware.ai/docs/models/elevenlabs-flash-v2-5#request-providersettings-elevenlabs-texttospeech-voicesettings-style)

- **Path**: `providerSettings.elevenlabs.textToSpeech.voiceSettings.style`
- **Type**: `float`
- **Min**: `0`
- **Max**: `1`

Controls style exaggeration of the voice. Higher values amplify the style of the original speaker but may increase latency.

#### [previousText](https://runware.ai/docs/models/elevenlabs-flash-v2-5#request-providersettings-elevenlabs-texttospeech-previoustext)

- **Path**: `providerSettings.elevenlabs.textToSpeech.previousText`
- **Type**: `string`
- **Max**: `1000`

Text that came before the current request. Improves speech continuity when concatenating multiple generations.

#### [nextText](https://runware.ai/docs/models/elevenlabs-flash-v2-5#request-providersettings-elevenlabs-texttospeech-nexttext)

- **Path**: `providerSettings.elevenlabs.textToSpeech.nextText`
- **Type**: `string`
- **Max**: `1000`

Text that comes after the current request. Improves speech continuity when concatenating multiple generations.

#### [applyTextNormalization](https://runware.ai/docs/models/elevenlabs-flash-v2-5#request-providersettings-elevenlabs-texttospeech-applytextnormalization)

- **Path**: `providerSettings.elevenlabs.textToSpeech.applyTextNormalization`
- **Type**: `string`
- **Default**: `auto`

Controls text normalization behavior (e.g., spelling out numbers).

**Allowed values**:

- `auto` Automatically decides whether to apply text normalization.
- `on` Always applies text normalization.
- `off` Skips text normalization entirely.

#### [applyLanguageTextNormalization](https://runware.ai/docs/models/elevenlabs-flash-v2-5#request-providersettings-elevenlabs-texttospeech-applylanguagetextnormalization)

- **Path**: `providerSettings.elevenlabs.textToSpeech.applyLanguageTextNormalization`
- **Type**: `boolean`
- **Default**: `false`

Enables language-specific text normalization for proper pronunciation. Currently only supported for Japanese. Warning: can significantly increase latency.

## Response Parameters

### [taskType](https://runware.ai/docs/models/elevenlabs-flash-v2-5#response-tasktype)

- **Type**: `string`
- **Required**: true
- **Value**: `audioInference`

Type of the task.

### [taskUUID](https://runware.ai/docs/models/elevenlabs-flash-v2-5#response-taskuuid)

- **Type**: `string`
- **Required**: true
- **Format**: `UUID v4`

UUID of the task.

### [audioUUID](https://runware.ai/docs/models/elevenlabs-flash-v2-5#response-audiouuid)

- **Type**: `string`
- **Required**: true
- **Format**: `UUID v4`

UUID of the output audio.

### [audioURL](https://runware.ai/docs/models/elevenlabs-flash-v2-5#response-audiourl)

- **Type**: `string`
- **Format**: `URI`

URL of the output audio.

### [audioBase64Data](https://runware.ai/docs/models/elevenlabs-flash-v2-5#response-audiobase64data)

- **Type**: `string`

Base64-encoded audio data.

### [audioDataURI](https://runware.ai/docs/models/elevenlabs-flash-v2-5#response-audiodatauri)

- **Type**: `string`
- **Format**: `URI`

Data URI of the output audio.

### [seed](https://runware.ai/docs/models/elevenlabs-flash-v2-5#response-seed)

- **Type**: `integer`

The seed used for generation. If none was provided, shows the randomly generated seed.

### [cost](https://runware.ai/docs/models/elevenlabs-flash-v2-5#response-cost)

- **Type**: `float`

Task cost in USD. Present when `includeCost` is set to `true` in the request.

## Examples

### Antique Planetarium Welcome Address (Text to Audio)

[Listen to audio](https://assets.runware.ai/examples/elevenlabs-flash-v2-5/fe45bcb3-b6c7-4f67-8f88-a21bd72ef066.mp3)

**Request**:

```json
{
  "taskType": "audioInference",
  "taskUUID": "8b925346-7add-40c7-a184-bc91ec4a95cb",
  "model": "elevenlabs:24@1",
  "seed": 82622,
  "speech": {
    "language": "en",
    "text": "Good evening, travelers. In a few moments, the dome above you will dim, and the first stars of tonight's program will appear. Please settle into your seats and let your eyes adjust to the dark. We will begin close to home, tracing the familiar line of the winter constellations, then drift outward beyond the bright edge of our neighborhood into regions where distance is measured in centuries of light. If you are joining us for the first time, you do not need to know any names. Simply look up, follow the guiding beam, and listen. By the end of our journey, the sky may feel a little larger, and Earth a little more precious."
  },
  "providerSettings": {
    "elevenlabs": {
      "textToSpeech": {
        "applyTextNormalization": "auto",
        "voiceSettings": {
          "stability": 0.42,
          "similarityBoost": 0.78,
          "style": 0.58,
          "useSpeakerBoost": true
        }
      }
    }
  }
}
```

**Response**:

```json
{
  "taskType": "audioInference",
  "taskUUID": "8b925346-7add-40c7-a184-bc91ec4a95cb",
  "audioUUID": "641f7e37-d5e9-4f75-b76d-014a17bde046",
  "audioURL": "https://am.runware.ai/audio/os/a12d13/ws/5/ai/641f7e37-d5e9-4f75-b76d-014a17bde046.mp3",
  "seed": 82622,
  "cost": 0.08947
}
```

---

### Emergency Tram Intercom Bulletin (Text to Audio)

[Listen to audio](https://assets.runware.ai/examples/elevenlabs-flash-v2-5/15651871-29f5-4f09-bf69-eea77370abee.mp3)

**Request**:

```json
{
  "taskType": "audioInference",
  "taskUUID": "4f10c705-5472-4315-a757-5c70f22f0a50",
  "model": "elevenlabs:24@1",
  "seed": 43900,
  "speech": {
    "text": "Attention passengers: service on the East Loop is temporarily paused between Harbor Gate and Pine Junction due to a signal fault. Shuttle buses are departing from Bay 3 every 12 minutes. If you are traveling to Riverside Terminal, remain on board for the alternate route announcement in 30 seconds. We apologize for the disruption and thank you for your patience.",
    "language": "en"
  },
  "providerSettings": {
    "elevenlabs": {
      "textToSpeech": {
        "voiceSettings": {
          "stability": 0.72,
          "similarityBoost": 0.78,
          "style": 0.34,
          "useSpeakerBoost": true
        },
        "applyTextNormalization": "on",
        "previousText": "Good afternoon, this is a network update.",
        "nextText": "Please listen for further instructions from station staff."
      }
    }
  }
}
```

**Response**:

```json
{
  "taskType": "audioInference",
  "taskUUID": "4f10c705-5472-4315-a757-5c70f22f0a50",
  "audioUUID": "57bf6f10-0a1a-4148-8c8a-31dc8710ea5c",
  "audioURL": "https://am.runware.ai/audio/os/a25d05/ws/5/ai/57bf6f10-0a1a-4148-8c8a-31dc8710ea5c.mp3",
  "seed": 43900,
  "cost": 0.05407
}
```

---

### Orbital Docking Countdown Brief (Text to Audio)

[Listen to audio](https://assets.runware.ai/examples/elevenlabs-flash-v2-5/ab26d893-4358-42d6-91c5-32224d11d3b3.mp3)

**Request**:

```json
{
  "taskType": "audioInference",
  "taskUUID": "8b10a718-b30e-468e-afd3-cf69336ad9a4",
  "model": "elevenlabs:24@1",
  "seed": 88075,
  "speech": {
    "text": "Attention inbound crew of the cargo shuttle Peregrine. Docking corridor C-12 is now active. Approach speed should not exceed 0.3 meters per second beyond the outer guide ring. Crosswinds from vent array 4 may cause minor drift on port-side thrusters. Window for final alignment opens in 18 seconds. If your guidance display flickers, maintain heading and await manual tone confirmation. Repeat: maintain heading. Dockmaster Hale authorizing clamp sequence on my count. Three. Two. One. Contact expected now.",
    "language": "en"
  },
  "providerSettings": {
    "elevenlabs": {
      "textToSpeech": {
        "applyTextNormalization": "on",
        "voiceSettings": {
          "stability": 0.42,
          "similarityBoost": 0.78,
          "style": 0.61,
          "useSpeakerBoost": true
        }
      }
    }
  }
}
```

**Response**:

```json
{
  "taskType": "audioInference",
  "taskUUID": "8b10a718-b30e-468e-afd3-cf69336ad9a4",
  "audioUUID": "d4b213ca-fd39-4446-a7ec-34774eb20619",
  "audioURL": "https://am.runware.ai/audio/os/a23d05/ws/5/ai/d4b213ca-fd39-4446-a7ec-34774eb20619.mp3",
  "seed": 88075,
  "cost": 0.09306
}
```

---

### Submersible Black Box Transmission (Text to Audio)

[Listen to audio](https://assets.runware.ai/examples/elevenlabs-flash-v2-5/b7fa7635-f3d0-4670-86d3-6e652c410187.mp3)

**Request**:

```json
{
  "taskType": "audioInference",
  "taskUUID": "8888535a-2ee9-4af6-99ed-b0376a3eb5ad",
  "model": "elevenlabs:24@1",
  "seed": 65534,
  "speech": {
    "text": "Archive buoy Kappa-seven, this is pilot Mirek Voss transmitting from bathysphere Nacre. If this reaches surface control, note the following in order. Primary floodgate sealed at fourteen minutes past shift change. Port thruster unresponsive after contact with loose cable or vine-like debris. Cabin pressure stable for now. I am reducing power to navigation glass and heating to preserve emergency cells. There is a repeating metallic tapping on the outer hull every eleven seconds. It is too regular to be current or drift. I have marked my position against the canyon wall using the last flare. Please do not send an automated ping burst; the echo in this trench is distorting sonar returns. Send a quiet approach team with a manual line. If Lena is on comms, tell her the charm tied to panel three was right. The old maps were wrong by nearly a full kilometer. End log, and please confirm receipt.",
    "language": "en"
  },
  "providerSettings": {
    "elevenlabs": {
      "textToSpeech": {
        "previousText": "Bathysphere Nacre emergency log begins after impact alarm.",
        "nextText": "Secondary note: oxygen reserve estimate pending manual recalculation.",
        "applyTextNormalization": "auto",
        "voiceSettings": {
          "stability": 0.42,
          "similarityBoost": 0.72,
          "style": 0.58,
          "useSpeakerBoost": true
        }
      }
    }
  }
}
```

**Response**:

```json
{
  "taskType": "audioInference",
  "taskUUID": "8888535a-2ee9-4af6-99ed-b0376a3eb5ad",
  "audioUUID": "8a21b704-fb41-4e19-9093-4dddbe9f1eb3",
  "audioURL": "https://am.runware.ai/audio/os/a04d20/ws/5/ai/8a21b704-fb41-4e19-9093-4dddbe9f1eb3.mp3",
  "seed": 65534,
  "cost": 0.14426
}
```