MODEL ID xai:tts@0

live

xAI Text-to-Speech

by xAI March 16, 2026

xAI Text-to-Speech converts text into natural-sounding spoken audio with a single API call. It offers five expressive voices (Eve, Ara, Leo, Rex, and Sal), inline speech tags for fine-grained control over pauses, laughter, whispers, and emphasis, and supports over 20 auto-detected languages.

API Options

Platform-level options for task execution and delivery.

taskType string required value: audioInference: Identifier for the type of task being performed

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

outputType string default: URL: Audio output type.

Allowed values 3 values

outputFormat 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 4 values

audioSettings object

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

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.

Properties 3 properties

audioSettings » bitrate bitrate integer min: 8: Audio bitrate in kbps.

audioSettings » channels channels integer default: 2: Number of audio channels. 1 for mono, 2 for stereo.

Allowed values 2 values

audioSettings » sampleRate sampleRate integer: Audio sample rate in Hz.

webhookURL string 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
PLATFORM

deliveryMethod string default: sync

Determines how the API delivers task results.

Allowed values 2 values

: Returns complete results directly in the API response.
: Returns an immediate acknowledgment with the task UUID. Poll for results using getResponse.

Learn more 1 resource

Task Polling
PLATFORM

uploadEndpoint string 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.

// 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 integer min: 60: Time-to-live (TTL) in seconds for generated content. Only applies when outputType is URL.

includeCost boolean default: false: Include task cost in the response.

numberResults 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 string required value: xai:tts@0

Identifier of the model to use for generation.

Learn more 3 resources

speech object required

Settings for speech generation.

Properties 3 properties

speech » text text string required: Text to convert to speech.

speech » voice voice string required default: auto: Voice identifier to use. Set to auto for automatic selection.

Allowed values 6 values

speech » language language string min: 1: Language code for speech generation.

Allowed values 20 values

taskType string required value: audioInference: Type of the task.

taskUUID string required UUID v4: UUID of the task.

audioUUID string required UUID v4: UUID of the output audio.

audioURL string URI: URL of the output audio.

audioBase64Data string: Base64-encoded audio data.

audioDataURI string URI: Data URI of the output audio.

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

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

Text to Audio

French Travel Narration

0:00

Request

{
  "taskType": "audioInference",
  "taskUUID": "583bb6a1-3d00-484f-a442-f1e61bf53dd7",
  "model": "xai:tts@0",
  "speech": {
    "text": "Bienvenue à Paris. <pause time=\"700ms\"/> Au lever du soleil, la Seine scintille comme un ruban d'or, les cafés s'éveillent lentement, et la ville murmure déjà ses histoires. <emphasis level=\"strong\">Écoutez</emphasis> le tintement des tasses, le pas pressé des passants, et le souffle léger du vent autour de la tour Eiffel. <pause time=\"500ms\"/> Ce voyage commence ici, avec élégance, lumière, et un peu de magie.",
    "voice": "eve",
    "language": "fr"
  }
}

Response

{
  "taskType": "audioInference",
  "taskUUID": "583bb6a1-3d00-484f-a442-f1e61bf53dd7",
  "audioUUID": "43b5f1e3-5853-42f9-9b34-a74c502f0001",
  "audioURL": "https://am.runware.ai/audio/os/a18d05/ws/5/ai/43b5f1e3-5853-42f9-9b34-a74c502f0001.mp3",
  "cost": 0.00174
}

Text to Audio

Expressive Story Narration

0:00

Request

{
  "taskType": "audioInference",
  "taskUUID": "e844d206-9c52-4597-bc4a-f83313956968",
  "model": "xai:tts@0",
  "speech": {
    "text": "The observatory lights dimmed one by one. [pause] Above the mountain, the sky opened like black velvet stitched with stars. \"Do you see it?\" she whispered. [whisper] \"The comet is early.\" [pause] Then, with a sudden laugh, she pointed east. [laugh] \"There! A silver flame across the dark.\" And for one breathless moment, the whole world stood still.",
    "voice": "eve",
    "language": "en"
  }
}

Response

{
  "taskType": "audioInference",
  "taskUUID": "e844d206-9c52-4597-bc4a-f83313956968",
  "audioUUID": "21467765-7783-4630-8c0d-e618dca19eb7",
  "audioURL": "https://am.runware.ai/audio/os/a01d21/ws/5/ai/21467765-7783-4630-8c0d-e618dca19eb7.mp3",
  "cost": 0.00147
}

Text to Audio

Spanish Travel Narration

0:00

Request

{
  "taskType": "audioInference",
  "taskUUID": "3cc30108-1696-446e-9d02-3c77a94183ef",
  "model": "xai:tts@0",
  "speech": {
    "text": "Bienvenidos a Sevilla, una ciudad de luz dorada, patios llenos de flores y música que vibra en cada rincón. Al caer la tarde, la Giralda se recorta contra el cielo, y las calles estrechas invitan a perderse sin prisa. [pause] Respira hondo. Escucha el murmullo de las plazas, el eco de los pasos sobre la piedra y la calidez de una noche que apenas comienza.",
    "voice": "eve",
    "language": "es-ES"
  }
}

Response

{
  "taskType": "audioInference",
  "taskUUID": "3cc30108-1696-446e-9d02-3c77a94183ef",
  "audioUUID": "2457d5b1-ee39-4d7a-af4d-aab1cee49ed6",
  "audioURL": "https://am.runware.ai/audio/os/a10d08/ws/5/ai/2457d5b1-ee39-4d7a-af4d-aab1cee49ed6.mp3",
  "cost": 0.0015
}

Text to Audio

Hindi Guided Meditation

0:00

Request

{
  "taskType": "audioInference",
  "taskUUID": "4a9f110c-7e7a-4f76-91f5-f5e9648d85af",
  "model": "xai:tts@0",
  "speech": {
    "text": "अपनी आँखें धीरे से बंद करें, और एक लंबी, गहरी साँस लें। <pause time=\"1.5s\"/> महसूस करें कि हर साँस के साथ आपका मन शांत होता जा रहा है। <pause time=\"1s\"/> आपके आसपास एक कोमल, सुनहरी रोशनी फैल रही है, जो आपको सुरक्षा, स्थिरता और सुकून का एहसास दे रही है। <pause time=\"1.5s\"/> अब धीरे-धीरे साँस छोड़ें, और दिन भर का तनाव अपने शरीर से बाहर जाने दें।",
    "voice": "ara",
    "language": "hi"
  }
}

Response

{
  "taskType": "audioInference",
  "taskUUID": "4a9f110c-7e7a-4f76-91f5-f5e9648d85af",
  "audioUUID": "dcbcc15a-5273-4c3a-b87c-569f95adf918",
  "audioURL": "https://am.runware.ai/audio/os/a19d05/ws/5/ai/dcbcc15a-5273-4c3a-b87c-569f95adf918.mp3",
  "cost": 0.00145
}