Text-to-Speech - Unifically

Generate high-quality speech audio from text using ElevenLabs models with an available voice ID or an on-demand clone made from caller-hosted sample URLs.

Model

elevenlabs/text-to-speech

Parameters

Parameter	Type	Required	Default	Description
`text`	string	Yes	-	Text to convert to speech. Character limits depend on `model_id` (see models below)
`voice`	string or array	Yes	-	Voice to use — see Voice Options
`model_id`	string	No	`eleven_flash_v2_5`	TTS model (see models below)
`with_timestamps`	boolean	No	`false`	Return character/word timing data alongside the audio
`speed`	number	No	`1.0`	Speech speed. Below `1.0` slower, above `1.0` faster. Shorthand for `voice_settings.speed`
`voice_settings`	object	No	-	Fine-tune voice behavior (see below)
`output_format`	string	No	`mp3_44100_128`	Audio output format (see formats below)
`language_code`	string	No	`auto`	ISO 639-1 language code to force language (e.g. `en`, `es`)
`seed`	integer	No	-	Seed for reproducible generation (0–4294967295)

Voice Options

The voice parameter accepts two forms:

Form	Example	Meaning
Voice ID	`"voice": "21m00Tcm4TlvDq8ikWAM"`	An available voice from `GET /v1/resources/elevenlabs/voices`.
Sample URLs	`"voice": ["https://.../a.mp3", "https://.../b.mp3"]`	A custom voice for this request only. The caller hosts the samples; Unifically does not retain them.

On-Demand Voice Samples

Pass sample URLs directly in the TTS request when you need a custom voice. All samples must contain the same speaker.

Send the sample URLs in voice on every request that uses the custom voice.
The caller is responsible for hosting and retaining the samples.
Samples are processed only for the current request and are not retained.
Up to 25 sample URLs are accepted per request.
Sample URLs must be direct downloads — redirects and link shorteners are rejected.
Supported audio formats: mp3, wav, ogg, opus, m4a, flac, webm.
Voice IDs must come from GET /v1/resources/elevenlabs/voices; IDs from a separate ElevenLabs account are not available to Unifically.

voice_settings

Field	Type	Default	Description
`stability`	number	`0.5`	0–1. Lower = more expressive/variable, higher = more monotone
`similarity_boost`	number	`0.75`	0–1. How closely the output adheres to the original voice
`style`	number	`0`	0–1. Style exaggeration. Values other than 0 may add latency
`speed`	number	`1.0`	Speech speed multiplier. Wins over top-level `speed` if both are set
`use_speaker_boost`	boolean	`true`	Boost similarity to the original speaker

Available Models

Model	Description	Languages	Char Limit
`eleven_flash_v2_5`	Default. Fastest and cheapest	32	40,000
`eleven_multilingual_v2`	Highest quality, most stable on long-form	29	10,000
`eleven_v3`	Most expressive	70+	5,000
`eleven_turbo_v2_5`	Deprecated by ElevenLabs — use `eleven_flash_v2_5` instead	32	40,000

Output Formats

Format	Description
`mp3_22050_32`	MP3 22.05kHz 32kbps
`mp3_44100_64`	MP3 44.1kHz 64kbps
`mp3_44100_96`	MP3 44.1kHz 96kbps
`mp3_44100_128`	MP3 44.1kHz 128kbps (default)
`mp3_44100_192`	MP3 44.1kHz 192kbps
`opus_48000_32`	Opus 48kHz 32kbps
`opus_48000_64`	Opus 48kHz 64kbps
`opus_48000_96`	Opus 48kHz 96kbps
`opus_48000_128`	Opus 48kHz 128kbps
`opus_48000_192`	Opus 48kHz 192kbps
`pcm_16000`	Raw PCM 16kHz
`pcm_22050`	Raw PCM 22.05kHz
`pcm_24000`	Raw PCM 24kHz
`pcm_44100`	Raw PCM 44.1kHz
`pcm_48000`	Raw PCM 48kHz
`wav_44100`	WAV 44.1kHz
`ulaw_8000`	μ-law 8kHz (Twilio)
`alaw_8000`	A-law 8kHz

Resources

Get available premade voices from the Resources API:

GET /v1/resources/elevenlabs/voices

Example — on-demand voice with timestamps

curl -X POST https://api.unifically.com/v1/tasks \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d '{
    "model": "elevenlabs/text-to-speech",
    "input": {
      "text": "Hello world, this is my cloned voice.",
      "voice": [
        "https://cdn.example.com/recording1.mp3",
        "https://cdn.example.com/recording2.wav"
      ],
      "model_id": "eleven_multilingual_v2",
      "with_timestamps": true,
      "speed": 1.1
    }
  }'

Response

{
  "code": 200,
  "success": true,
  "data": {
    "task_id": "abc123def456",
    "status": "processing"
  }
}

Completed Response

Poll GET /v1/tasks/{task_id} until status is completed:

{
  "code": 200,
  "success": true,
  "data": {
    "task_id": "abc123def456",
    "status": "completed",
    "output": {
      "audio_url": "https://files.unifically.com/audio/abc123.mp3",
      "alignment": {
        "characters": ["H", "e", "l", "l", "o"],
        "character_start_times_seconds": [0.0, 0.081, 0.15, 0.21, 0.26],
        "character_end_times_seconds": [0.081, 0.15, 0.21, 0.26, 0.32]
      },
      "normalized_alignment": { "...": "same shape, for the spoken (normalized) text" },
      "words": [
        { "word": "Hello", "start": 0.0, "end": 0.32 },
        { "word": "world,", "start": 0.38, "end": 0.79 }
      ]
    }
  }
}

alignment maps your original text; normalized_alignment maps the text as spoken (numbers and abbreviations expanded).
words is derived from alignment — use it directly for captions and audio/video sync. Punctuation stays attached to its word.
Without with_timestamps, the output contains only audio_url.

Volume discounts are available for almost all models. Reach out at contact@unifically.com to discuss custom pricing.

​Model

​Parameters

​Voice Options

​On-Demand Voice Samples

​voice_settings

​Available Models

​Output Formats

​Resources

​Example — on-demand voice with timestamps

​Response

​Completed Response

Model

Parameters

Voice Options

On-Demand Voice Samples

voice_settings

Available Models

Output Formats

Resources

Example — on-demand voice with timestamps

Response

Completed Response