OpenAI

OpenAI is a text-to-speech plugin. It synthesizes the LLM’s reply into the agent’s voice using OpenAI’s TTS models. It occupies the pipeline’s tts slot.

Setup

Set your OpenAI API key in the worker environment. Generate a key from the OpenAI dashboard:

export OPENAI_API_KEY=<key>

Usage

Import the plugin and pass it to the pipeline’s tts slot.

from zrt.plugins import OpenAITTS

tts = OpenAITTS(
    model="gpt-4o-mini-tts",
    voice="ash",
)

# Pipeline(tts=tts, ...)

Speed control

Use speed to adjust the speaking rate. The value is a multiplier in the range 0.25 - 4.0; leaving it unset uses the provider default of 1.0:

Python

from zrt.plugins import OpenAITTS

tts = OpenAITTS(
    model="gpt-4o-mini-tts",
    voice="marin",
    speed=1.1,
)

Parameters

Constructor parameters for the Python SDK (OpenAITTS).

Parameter	Type	Default	Description
`api_key`	`str`	`None`	OpenAI API key. Falls back to the `OPENAI_API_KEY` environment variable when unset.
`voice`	`str`	`"ash"`	Built-in voice name (e.g. `"marin"`, `"cedar"`, `"ash"`, `"coral"`).
`model`	`str`	`"gpt-4o-mini-tts"`	TTS model: `"gpt-4o-mini-tts"` (newest, most capable), `"tts-1"` (lower latency), or `"tts-1-hd"` (higher quality).
`sample_rate`	`int`	`24000`	Output audio sample rate in Hz.
`speed`	`float`	`None`	Speaking speed multiplier (0.25 - 4.0). `None` uses the provider default of 1.0.
`stream`	`bool`	`True`	When `True`, audio is returned as a streaming response; `False` requests the full audio before playback.

Import paths

SDK	Import	Constructor
Python	`from zrt.plugins import OpenAITTS`	`OpenAITTS(...)`
JavaScript	-	Coming soon
Go	-	Coming soon

The synthesized audio is streamed back to the caller as the final stage of the pipeline.

Plugins

Inference Gateway

Speech-to-text

LLM

Text-to-speech

Realtime models

Avatars

Turn detection

Voice activity detection

Noise cancellation

Setup

Usage

Speed control

Parameters

Import paths

​Setup

​Usage

​Speed control

​Parameters

​Import paths

Setup

Usage

Speed control

Parameters

Import paths