End-of-Utterance Timeout

End-of-utterance (EOU) timeout controls how long the model waits in silence after a speaker stops talking before it flushes the transcript as final. Tuning this value lets you balance responsiveness against cutting users off mid-thought.

How It Works

When speech pauses, Pulse starts a silence timer. If no additional speech is detected within the eou_timeout_ms window, the current transcript segment is returned with is_final: true.

• Lower values: faster turn detection, but more likely to split natural pauses
• Higher values: more tolerant of pauses, but slower finalization

Enabling EOU Timeout

Add eou_timeout_ms to your WebSocket connection query parameters. The value must be an integer from 100 to 10000. Default is 800.

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const url = new URL("wss://api.smallest.ai/waves/v1/stt/live?model=pulse");
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url.searchParams.append("language", "en");
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url.searchParams.append("encoding", "linear16");
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url.searchParams.append("sample_rate", "16000");
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url.searchParams.append("eou_timeout_ms", "300"); // fast turn-taking
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const ws = new WebSocket(url.toString(), {
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  headers: {
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    Authorization: `Bearer ${API_KEY}`,
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  },
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});

How to Tune It

Start at the default 800 ms, then tune based on your use case:

• Decrease for voice agents that need faster turn-taking
• Increase for meeting or dictation workflows where speakers pause mid-sentence

Tuning Guide

Trade-offs

Example

A voice agent needs to detect when the caller is done speaking and respond immediately:

$
wss://api.smallest.ai/waves/v1/stt/live?model=pulse&language=en&encoding=linear16&sample_rate=16000&eou_timeout_ms=300

A meeting transcription system should wait for natural pauses:

$
wss://api.smallest.ai/waves/v1/stt/live?model=pulse&language=en&encoding=linear16&sample_rate=16000&eou_timeout_ms=1500