Sonna
API ReferenceText-to-Speech ModelsElevenLabs

Eleven v3

ElevenLabs Eleven v3 — the most expressive TTS model, 70+ languages with audio tags.

ElevenLabs' most expressive model — 70+ languages with inline audio-tag control. Best for short, performance-heavy content (ads, characters, trailers) where emotional range matters more than length.

EndpointPOST /api/v1/tts/synthesize
Model ID (ttsModel)eleven-v3
ProviderElevenLabs (paid access)
Character Limit5,000
Cost2,100 / 1K chars

Shared conventions

Auth, the voice→provider rule, rate limits, and the full error table are on the Speech API page. This page covers only what's specific to Eleven v3.


How Eleven v3 expression works

v3 controls delivery through inline audio tags in your text — [laughs], [whispers], [excited], [sighs] — combined with stability. It has no speed or style sliders: the speed and style_exaggeration fields are ignored by v3 (those belong to Multilingual v2 / Flash). Use tags for emotion.

Match the voice's supported models

Only a small curated set of voices is eleven_v3-optimized (see a voice's metadata.supported_models from GET /api/v1/tts/voices). v3 still renders on any voice, but forcing it on a voice tuned for v2/Flash — especially Professional Voice Clones — lowers similarity. For those, prefer Multilingual v2.


Request

Body

ParameterTypeRequiredDescription
textstringYesText to synthesize (max 5,000 chars). Supports inline [audio tags].
voicestringYesAn ElevenLabs voice ID from GET /api/v1/tts/voices
ttsModelstringYesMust be "eleven-v3"
stabilitynumberNoVoice stability 0.01.0 · Default: 0.5
similarity_boostnumberNoSimilarity to source voice 0.01.0 · Default: 0.75
speaker_boostbooleanNoEnhance speaker clarity · Default: true
language_overridebooleanNoForce the voice's native language · Default: false
response_formatstringNo"mp3_44100_128" "pcm_8000" "pcm_16000" "pcm_22050" "pcm_24000" · Default: "mp3_44100_128"
titlestringNoTitle for the saved project
{
  "text": "[excited] Welcome to Sonna! [whispers] Your audio is ready.",
  "voice": "db4e815d-00aa-43e6-99cf-0d9b4db9a07a",
  "ttsModel": "eleven-v3",
  "stability": 0.5,
  "similarity_boost": 0.75
}

Response (200 OK)

{
  "url": "https://cdn.sonnalabs.app/sonna/api-ephemeral/tts/paid/user123/abc123.mp3",
  "remainingCredits": 99580,
  "projectCreated": true
}

Errors (400 TEXT_TOO_LONG over 5,000 chars, 403 PAID_ACCESS_REQUIRED, 409, 429, 503) follow the shared Speech API table.

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