Fish Audio

Fish Audio is a text-to-speech service built around voice cloning: you create a voice in your Fish Audio account from a short recording, and jambonz speaks with it. Fish Audio tuning is passed in synthesizer.options.

{
  "verb": "say",
  "text": "Thanks for calling, how can I help you today?",
  "synthesizer": {
    "vendor": "fishaudio",
    "voice": "802e3bc2b27e49c2995d23ef70e6ac89",
    "options": {
      "latency": "balanced",
      "speed": 1.1
    }
  }
}

You can also set these in the portal under Extra Options on the speech credential, in which case they apply to every request that uses that credential. Settings supplied on the verb take precedence.

Voices

A Fish Audio voice is a model id, which Fish Audio calls a reference_id. The portal lists the voices you have created in your Fish Audio account, grouped by language, plus Fish Audio default voice. Choosing the default voice (voice default) sends no reference_id, and Fish Audio speaks with its own default voice.

To use a voice from Fish Audio’s public library, which the portal does not list, put its id in voice, or in the reference_id option. reference_id takes precedence over voice.

The voice decides the language. jambonz does not send synthesizer.language to Fish Audio.

Model

jambonz uses Fish Audio’s s2.1-pro model, which is also Fish Audio’s default. It is the only model the portal offers. (Fish Audio retires its older s1 model on December 31, 2026.)

Options

Every option is optional. An option you don’t set is not sent, so Fish Audio’s own default applies.

Endpoint override

Fish Audio credentials have no API base URL field in the portal. If you need to point at a non-default endpoint, such as a proxy, set api_uri in Extra Options alongside the tuning fields:

{
  "api_uri": "my-proxy.example.com",
  "latency": "balanced"
}

Leave it out to use Fish Audio’s standard endpoint (api.fish.audio).

Streaming

Fish Audio supports TTS streaming, so it can be driven token by token from an LLM using tts:tokens, for example from the agent verb.

Fish Audio’s streaming connection serves one response and has no way to cancel it. jambonz works around this:

• Each turn opens a new connection. The connection setup, about 0.3 seconds in our testing, is added to the time before the first audio of every turn.
• Barge-in closes the connection. When the caller interrupts, jambonz drops the connection so the interrupted response stops at once, and the next turn opens a fresh one.

Fish Audio does not return word-level timestamps, so on barge-in jambonz cannot trim the assistant’s turn to the words the caller actually heard.

Concurrency

Fish Audio limits how many requests an account can run at once, based on how much it has prepaid: 5 for accounts under $100, more at higher tiers. Each call that is speaking with Fish Audio uses one. Check your Fish Audio limit against the number of simultaneous calls you expect.