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Community-maintained integration. This service is built and maintained by Gandr. Pipecat does not test or officially support it. Please report issues and request changes on the source repository. Learn more about community integrations.

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Overview

GandrTTSService converts text to speech using Gandr. It holds a single WebSocket open and reuses it across turns rather than opening one per utterance, which is what keeps steady-state first-audio latency low.

Source Repository

Source code, examples, and issues for the Gandr integration

Gandr Website

Voices, languages, and pricing

API Keys

Create a Gandr API key

API Reference

The full HTTP and WebSocket contract

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Installation

This is a community-maintained package distributed separately from pipecat-ai:

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Prerequisites

  1. Gandr account: sign up at gandr.ai
  2. API key: a gnd_… key from your account page

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Required environment variables

  • GANDR_API_KEY: your Gandr API key (required)

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Configuration

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str
required
Gandr API key (gnd_…). Raises ValueError if empty or whitespace.
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str
default:"wss://tts.gandr.ai/ws"
WebSocket endpoint. Leave as the default unless you have been given a different one.
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GandrTTSService.InputParams
default:"None"
Voice, language and expression configuration. See Input parameters.
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TextAggregationMode
default:"None"
How incoming text is aggregated before synthesis.
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float
default:"30.0"
How long to wait for an utterance’s closing frame before treating it as failed.
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float
default:"0.5"
How long to wait before retrying after the server answers busy.
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int
default:"3"
Total attempts per utterance, including retries for busy and for voice registration.
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bool
default:"True"
On barge-in, drop and reopen the connection so the next turn’s audio is not queued behind audio the listener has already interrupted. See Interruptions.

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Input parameters

Passed via params=GandrTTSService.InputParams(...). Stock voices: gandr-mia, gandr-ava, gandr-jenny, gandr-dane, gandr-leo, gandr-lewis.

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Languages

language takes a bare two-letter code: 23 languages are supported. Examples: en, es, fr, de, pt, ar, zh, ja.
A region suffix such as en-GB or zh-CN is not recognised and the request falls back to English without raising an error. If you are populating this from a browser or OS locale, strip the region first.

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Usage example

A complete runnable pipeline is in examples/foundational/gandr_tts_basic.py.

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Interruptions

The wire protocol has no cancel frame. On barge-in the service therefore drops the connection and reopens it, rather than draining audio nobody is going to hear. Set reconnect_on_interruption=False to keep the connection instead and discard the interrupted render client-side, at the cost of the next turn waiting for that render to finish.

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Notes

The first turn on a fresh connection is slower while the session voice cache fills. Every turn after it is materially quicker, which is why the connection is held warm across turns. A benchmark that measures only turn one is measuring the cache filling rather than the engine. Gandr’s published steady-state numbers: first audio byte in 146 ms over the open internet, and 116 ms p50 first audio, server side warm. Both are byte-arrival metrics rather than heard-sound timing: the engine’s first rendered chunk can be silence.
Requests are capped at 2,000 characters. Longer text is split losslessly by split_for_request before sending; you do not need to pre-chunk.
Every failure path closes the turn with TTSStoppedFrame, so a pipeline cannot hang waiting on a connection that has died.

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Compatibility

Tested with Pipecat v1.7.0 on Python 3.12.11: clean virtual environment, install, import, unit tests, and service construction. Declared support is pipecat-ai>=0.0.108,<2.0.0.