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

# Google Cloud STT

> Use the Google Cloud Speech-to-Text plugin in a Zero Runtime pipeline. Setup, options, and usage in Python and JavaScript.

Google Cloud Speech-to-Text is a **speech-to-text** plugin. It transcribes the caller's
audio into text for the LLM using Google Cloud's Speech-to-Text V2 streaming API.

## Setup

Google Cloud STT authenticates with a Google Cloud service account rather than a simple API
key. Point Application Default Credentials at your service-account JSON. Create the service account and key in the [Google Cloud console](https://console.cloud.google.com/apis/credentials):

```bash theme={null}
export GOOGLE_APPLICATION_CREDENTIALS=/path/to/service-account.json
```

<Note>
  In the Python SDK you can also pass the service-account JSON path (or raw JSON string) as the
  `api_key` argument. The value is used directly as the service-account credentials; it is not
  written to the `GOOGLE_APPLICATION_CREDENTIALS` environment variable.
</Note>

## Usage

Import the plugin and pass it to the pipeline's `stt` slot.

<CodeGroup>
  ```python Python theme={null}
  from zeroruntime.plugins import GoogleSTT

  stt = GoogleSTT(
      languages="en-US",
      model="latest_long",
  )

  # Pipeline(stt=stt, ...)
  ```

  ```typescript Node JS theme={null}
  import { GoogleSTT } from '@zeroruntime/js-sdk/plugins';

  const stt = GoogleSTT({
    languages: 'en-US',
    model: 'latest_long',
  });

  // Pipeline({ stt, ... })
  ```
</CodeGroup>

## Parameters

*Constructor parameters for `GoogleSTT`. The Python and Node JS SDKs share these field names.*

| Parameter | Type | Default | Description |
| - | - | - | - |
| `credentials_json` | `str` | `None` | Service-account credentials as a raw JSON string or a path to a JSON key file. Takes highest precedence. |
| `service_account_path` | `str` | `None` | Path to a service-account JSON key file. Used when `credentials_json` is not set. |
| `api_key` | `str` | `None` | Fallback credential source; the value is treated as a JSON file path (or raw JSON) first. Used only when the above are absent. Service-account auth is recommended for STT. |
| `project_id` | `str` | `None` | Google Cloud project ID. Extracted from the service-account JSON when not set. |
| `languages` | `str \| list[str]` | `"en-US"` | Language code(s) to recognize. The first entry is the primary language. |
| `model` | `str` | `"latest_long"` | Google Cloud Speech recognition model. |
| `sample_rate` | `int` | `48000` | Target sample rate (Hz). Matches the native input rate so no resampling occurs; set a lower value (e.g. `16000`) to downsample. |
| `interim_results` | `bool` | `True` | Emit partial transcripts while the caller is still speaking. |
| `punctuate` | `bool` | `True` | Add automatic punctuation to transcripts. |
| `min_confidence_threshold` | `float` | `0.0` | Drop results below this confidence. `0.0` disables filtering. |
| `location` | `str` | `"us"` | Cloud Speech-to-Text regional endpoint: `"us"` or `"eu"`. |
| `profanity_filter` | `bool` | `False` | Mask profane words in transcripts. |
| `enable_voice_activity_events` | `bool` | `False` | Emit server-side speech-start/-end events independently of transcripts. |
| `speech_start_timeout` | `float` | `None` | Seconds to wait for speech to begin before a voice-activity timeout fires. `None` uses the API default. |
| `speech_end_timeout` | `float` | `None` | Seconds of silence after speech before an end-of-speech event fires. `None` uses the API default. |
| `audio_channel_count` | `int` | `1` | Number of audio channels in the input (mono by default). |
| `min_speaker_count` | `int` | `None` | Minimum expected speakers for diarization. `None` disables diarization. |
| `max_speaker_count` | `int` | `None` | Maximum expected speakers for diarization. `None` disables diarization. |

## Import paths

| SDK | Import | Constructor |
| - | - | - |
| Python | `from zeroruntime.plugins import GoogleSTT` | `GoogleSTT(...)` |
| Node JS | `import { GoogleSTT } from '@zeroruntime/js-sdk/plugins'` | `GoogleSTT({ ... })` |

Transcribed text passes to the [LLM](/runtime-sdk/plugins/llm/google) once
[turn detection](/runtime-sdk/plugins/turn-detection/namo) decides the caller has finished speaking.


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