ElevenLabs

ElevenLabs synthesizes speech and transcribes it back. Here that is /v1/audio — five operations, OpenAI-shaped for speech and transcription.

ElevenLabs turns text into speech, and audio back into text, with sound effects and music beside it. /v1/audio (5 operations) covers the same four verbs: speech and transcriptions in the OpenAI shape, and voice, music and foley for the Zen family's own.

Nouns

ElevenLabs	Hanzo
`client.text_to_speech.convert(...)`	`POST /v1/audio/speech` — `model`, `input`, optional `voice`
`POST /v1/text-to-speech/{voice_id}`	The same route; the voice is a body field, not a path segment
`model_id`, e.g. `eleven_v3`	`model`, e.g. `qwen3-tts-voicedesign`
`output_format`, e.g. `mp3_44100_128`	`response_format` — `mp3` by default
`client.speech_to_text.convert(...)`	`POST /v1/audio/transcriptions` — multipart `file` and `model`, with `language` and `response_format`
`client.text_to_sound_effects.convert(...)`	`POST /v1/audio/foley`
`client.music.compose(...)`	`POST /v1/audio/music`
The Zen-native speech verb	`POST /v1/audio/voice`, with `zen-voice`
`xi-api-key` header	`Authorization: Bearer $HANZO_API_KEY`

model resolves to its provider through the same routing every other modality uses, so a node you registered as a TTS provider is reached the same way a hosted one is.

The call

ElevenLabs:

from elevenlabs.client import ElevenLabs

elevenlabs = ElevenLabs()   # ELEVENLABS_API_KEY in the environment

audio = elevenlabs.text_to_speech.convert(
    text="The first move is what sets everything in motion.",
    voice_id="JBFqnCBsd6RMkjVDRZzb",
    model_id="eleven_v3",
    output_format="mp3_44100_128",
)
with open("out.mp3", "wb") as f:
    for chunk in audio:
        f.write(chunk)

Hanzo — the bytes stream straight back, so write them to a file:

curl -X POST https://api.hanzo.ai/v1/audio/speech \
  -H "Authorization: Bearer $HANZO_API_KEY" \
  -H 'Content-Type: application/json' \
  -d '{
    "model": "qwen3-tts-voicedesign",
    "input": "The first move is what sets everything in motion.",
    "response_format": "mp3"
  }' \
  -o out.mp3

model and input are the only required fields. voice is optional and is carried to the provider when set. Because the body is OpenAI's, an OpenAI client pointed at https://api.hanzo.ai/v1 reaches this endpoint with no other change.

Transcription is the mirror of it — multipart, file and model, where the model is one of the whisper family:

curl -X POST https://api.hanzo.ai/v1/audio/transcriptions \
  -H "Authorization: Bearer $HANZO_API_KEY" \
  -F [email protected] \
  -F model=whisper-1

Read GET /v1/models for the ids this gateway currently resolves for each modality, rather than hardcoding one.

What does not carry

No voice library. ElevenLabs' catalogue of voices, voices.search(), per-voice settings, voice design and instant or professional cloning have no equivalent. voice is an optional string carried to the provider; there is no route that lists what it accepts, and there is nothing that creates a voice.

Only two of the five operations are shaped like OpenAI's. speech and transcriptions are. voice, music and foley are Zen-native verbs and reject a non-Zen model, so they are not a drop-in for an ElevenLabs client.

Speech input is capped at 4096 characters. Longer text is refused rather than truncated. Chunk it yourself.

No word-level timestamps, no alignment, no dubbing, no voice changer. convert_with_timestamps, the dubbing API and the speech-to-speech endpoints have nothing on this side.

A publishable key is refused here. /v1/audio/speech requires a secret key. That is not a general rule about the platform — it is this endpoint, because it synthesizes billable audio, and a publishable key lives in browsers.

No real-time socket. ElevenLabs streams synthesis over a WebSocket for conversational latency. This is a request and a response, with the audio bytes streamed back on it.

Nouns

The call

What does not carry

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