Batch TTS API

POST /tts/speak synthesises speech from text and streams the audio back — standalone, no call required. Same API key, same balance as your agents. No agent required — you pick the provider and voice directly.

Synthesise speech

POST /tts/speak

{
  "text": "Your appointment is confirmed for Friday at 2pm.",
  "voice_id": "autumn",
  "provider": "groq",
  "model": null,
  "language": "en",
  "rate": 1.0,
  "volume": 1.0,
  "format": "mp3"
}

The response is a chunked audio stream with the matching Content-Type (audio/mpeg for mp3, etc.). Two response headers:

Caching (not determinism)

TTS providers do not guarantee byte-identical audio for the same input across calls, so Wakili does not promise deterministic output. Instead it caches: the first synthesis for a given (provider, model, voice_id, rate, volume, format, text) tuple is stored, and every later request with the exact same tuple replays the stored audio. A cache hit is not billed (X-Wakili-Cache: hit, X-Wakili-Cost-Usd: 0). If you need the same audio twice, request it with identical parameters and the second call is free.

List voices

GET /tts/voices?language=en

{
  "language": "en",
  "voices": {
    "groq": ["autumn", "diana", "hannah", "austin", "daniel", "troy"],
    "elevenlabs": ["21m00Tcm4TlvDq8ikWAM", "..."]
  }
}

Omit language for the full list. Providers whose model is multilingual are always included; single-language voices are filtered to the requested language.

Billing

You pay the provider's list price for the character count, plus a flat 10% routing fee:

cost_usd = upstream_cost_usd × 1.10

upstream_cost_usd is the per-1000-character list price for the chosen provider. Debited from the same balance as calls. 402 with code: "insufficient_balance" if the balance can't cover it (checked before synthesis). A cache hit skips billing entirely.

Errors