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Usage guide

Setup, environment variables, and Python/JavaScript/Go usage examples.

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NeuphonicTTS

Neuphonic text-to-speech provider for low-latency, streaming voice synthesis. Synthesizes audio from text using Neuphonic’s hosted TTS service, with selectable voices, multilingual support, and configurable output sampling rate.

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Constructor

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api_key
str | None
Neuphonic API key. Falls back to the NEUPHONIC_API_KEY environment variable when omitted.
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voice_id
Optional[str]
Voice identifier (a UUID string from your Neuphonic voice library). The chosen voice also determines which underlying model is used. Defaults to None, letting Neuphonic select a default voice.
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lang_code
str
default:"en"
Language code for synthesis. Defaults to 'en'. Other supported codes include 'es', 'pt', 'fr', 'de', 'zh', 'ja', 'ko', and 'ur'.
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sampling_rate
int
default:"22050"
Output audio sampling rate in Hz. Defaults to 22050. Valid values: 8000, 16000, 22050, 24000.

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aclose

Release any resources held by the provider.

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emit

Emit an event, invoking all registered handlers with the given arguments. Handlers are called in registration order. Coroutine handlers are scheduled on the running event loop. If the emitter is closed, the call is a no-op.
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event
T
required
The event to emit.

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interrupt

Interrupt and cancel the current synthesis for the active session, if any.

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off

Remove a previously registered handler for an event. If the handler is not registered for the event, the call is a no-op.
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event
T
required
The event the handler was registered for.
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callback
Callable[..., Any]
required
The handler to remove.

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on

Register a handler for an event. Can be used directly by passing a callback, or as a decorator when callback is omitted.
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event
T
required
The event to listen for.
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callback
Callable[..., Any] | None
The handler to invoke when the event is emitted. If None, a decorator is returned that registers the decorated function.
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returns
Callable[..., Any]
The registered callback when callback is provided, otherwise a decorator that registers and returns the function it wraps.

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on_first_audio_byte

Register the callback invoked when the first audio byte is produced.
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callback
'Callable[[int, int], Awaitable[None] | None]'
required
A callable, optionally async, invoked with synthesis timing information when the first audio byte is emitted.

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synthesize

Synthesize the given text into speech. Implementations should convert the text to audio. The default behavior forwards the text to the active session for playback when one is present.
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text
Any
required
The text to synthesize; coerced to a string if needed.