> ## Documentation Index
> Fetch the complete documentation index at: https://developers.telnyx.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Endpointing

> Configure silence-based endpointing for utterance boundary detection on the Telnyx Speech-to-Text WebSocket endpoint (Deepgram, xAI, Google, Speechmatics, and Soniox).

<Info>**Deepgram, xAI, Google, Speechmatics, and Soniox.** Other engines ignore this parameter.</Info>

Controls how long the engine waits after silence before finalizing an utterance.

<Warning>
  **Soniox has a different valid range.** When `transcription_engine=Soniox`, this parameter maps to `max_endpoint_delay_ms` and must be between **500 and 3000 ms**. Values outside that range are rejected. The default (100 ms) and the low-value examples below apply to Deepgram, xAI, Google, and Speechmatics only.
</Warning>

```
# Deepgram / xAI / Google / Speechmatics
wss://api.telnyx.com/v2/speech-to-text/transcription?endpointing=300

# Soniox (500–3000 ms)
wss://api.telnyx.com/v2/speech-to-text/transcription?transcription_engine=Soniox&endpointing=1000
```

Default: `100` ms (not applicable to Soniox — Soniox endpointing is disabled unless a value in the 500–3000 ms range is provided).

## Values

| Value        | Behavior                                                                |
| ------------ | ----------------------------------------------------------------------- |
| Integer (ms) | Finalize after this many ms of silence. Lower = faster but more splits. |
| `"false"`    | Disable endpointing entirely. No automatic utterance boundaries.        |

## Trade-offs

**Low values (50–100 ms)** — Fast response. Utterances may split mid-sentence on short pauses. *(Deepgram, xAI, Google, Speechmatics only — below Soniox minimum.)*

**High values (300–1000 ms)** — More complete sentences. Higher latency before finalization.

**Soniox range (500–3000 ms)** — Minimum 500 ms. Use 500–800 ms for responsive turn detection, 1000–3000 ms for longer utterances with natural pauses.

**Disabled (`"false"`)** — No automatic splits. Use `Finalize` control messages to manually trigger boundaries, or rely on `CloseStream` for a single final transcript.

## Interaction With Utterance End

When endpointing triggers, Deepgram sends the final transcript followed by an utterance end event (if `utterance_end_ms` is configured server-side — currently 1000 ms).

```json theme={null}
{"transcript": "Hello, how are you?", "is_final": true}
{"transcript": "", "is_final": true, "utterance_end": true}
```

The utterance end marker signals "this speaker turn is done." See [Messages](/docs/voice/stt/websocket-streaming/responses) for details.