xAI TTS 1 - PoYo AI

curl --request POST \
  --url https://api.poyo.ai/api/generate/submit \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "model": "xai-tts-1",
  "callback_url": "https://your-domain.com/callback",
  "input": {
    "text": "Welcome to the xAI text to speech demo. [pause] <whisper>This line is softer.</whisper> [laugh] Now back to a clear product narration voice.",
    "voice": "eve",
    "language_code": "auto",
    "output_format": {
      "codec": "mp3",
      "sample_rate": 24000,
      "bit_rate": 128000
    }
  }
}
'

{
  "code": 200,
  "data": {
    "task_id": "task-unified-1757165031-uyujaw3d",
    "status": "not_started",
    "created_time": "2026-06-25T10:30:00"
  }
}

{
  "code": 200,
  "error": {
    "message": "<string>",
    "type": "<string>"
  }
}

{
  "code": 200,
  "error": {
    "message": "<string>",
    "type": "<string>"
  }
}

POST

api

generate

submit

curl --request POST \
  --url https://api.poyo.ai/api/generate/submit \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "model": "xai-tts-1",
  "callback_url": "https://your-domain.com/callback",
  "input": {
    "text": "Welcome to the xAI text to speech demo. [pause] <whisper>This line is softer.</whisper> [laugh] Now back to a clear product narration voice.",
    "voice": "eve",
    "language_code": "auto",
    "output_format": {
      "codec": "mp3",
      "sample_rate": 24000,
      "bit_rate": 128000
    }
  }
}
'

{
  "code": 200,
  "data": {
    "task_id": "task-unified-1757165031-uyujaw3d",
    "status": "not_started",
    "created_time": "2026-06-25T10:30:00"
  }
}

{
  "code": 200,
  "error": {
    "message": "<string>",
    "type": "<string>"
  }
}

{
  "code": 200,
  "error": {
    "message": "<string>",
    "type": "<string>"
  }
}

After submission, a task_id will be returned. If you provided a callback_url, when the task status becomes finished or failed, a POST request will be sent to the callback_url.
Regardless of whether callback_url is provided, you can retrieve the result through the unified Query Task Status endpoint.

xai-tts-1 converts a text into low-latency expressive speech audio using xAI TTS through fal. Results are returned as task files, matching the standard image, video, 3D, and audio task response structure.

Models

xai-tts-1 - xAI TTS v1 text-to-speech generation

Required parameters

text: Text to convert to speech
- Length: 1-15000 characters
- Supports expressive speech tags such as [laugh], [pause], [sigh], <whisper>text</whisper>, and <slow>text</slow>

Optional parameters

voice: Voice preset. Supported values: eve, ara, rex, sal, leo. Default: eve
language_code: BCP-47 language code or auto for automatic detection. Default: auto
output_format: Audio output configuration object:
- codec: mp3, wav, pcm, mulaw, or alaw. Default: mp3
- sample_rate: 8000, 16000, 22050, 24000, 44100, or 48000. Default: 24000
- bit_rate: 32000, 64000, 96000, 128000, 192000, or null. Only applicable for MP3. Default: 128000

Examples

{
  "model": "xai-tts-1",
  "callback_url": "https://your-domain.com/callback",
  "input": {
    "text": "Welcome to the xAI text to speech demo. [pause] <whisper>This line is softer.</whisper> [laugh] Now back to a clear product narration voice.",
    "voice": "eve",
    "language_code": "auto",
    "output_format": {
      "codec": "mp3",
      "sample_rate": 24000,
      "bit_rate": 128000
    }
  }
}

Notes

Supported Languages

Supported values: auto, en, ar-EG, ar-SA, ar-AE, bn, zh, fr, de, hi, id, it, ja, ko, pt-BR, pt-PT, ru, es-MX, es-ES, tr, vi.

PoYo’s public parameter name is language_code; it is mapped to fal’s language field upstream.
PoYo’s public parameter name is text; it is mapped to fal’s text field upstream.
Query status through the standard task status API.
Successful responses return files, where the generated speech uses file_type: audio.

Authorizations

Authorization

string

header

required

All API endpoints require Bearer Token authentication.

Create an API key: sign in to PoYo, open Dashboard → API Key at poyo.ai/dashboard/api-key, and click to create a key.

Add it to the request header:

Authorization: Bearer YOUR_API_KEY

Body

application/json

model

enum<string>

required

Model identifier.

Available options:

xai-tts-1

Example:

"xai-tts-1"

input

object

required

Show child attributes

callback_url

string<uri>

Webhook callback URL for result notifications

Example:

"https://your-domain.com/callback"

Response

Task submitted successfully

code

enum<integer>

required

Business status code. 200 means success; any other value means the request failed. Always check this field: some validation errors return HTTP 200 with code: 400 in the body.

200: Success
400: Invalid request parameters
401: Missing or invalid API key
402: Insufficient credits
403: Permission denied
404: Resource not found
408: Request timeout
429: Rate limit exceeded
500: Internal server error
502: Upstream service error
503: Service unavailable

See Error Codes for details.

Available options:

200,

400,

401,

402,

403,

404,

408,

429,

500,

502,

503

Example:

200

data

object

required

Show child attributes

​Models

​Required parameters

​Optional parameters

​Examples

​Notes

​Supported Languages

Authorizations

Body

Response

Models

Required parameters

Optional parameters

Examples

Notes

Supported Languages