Google

Overview

GoogleSTTService provides real-time speech recognition using Google Cloud’s Speech-to-Text V2 API with support for 125+ languages, multiple models, voice activity detection, and advanced features like automatic punctuation and word-level confidence scores.

Google STT API Reference

Pipecat’s API methods for Google Cloud STT integration

Example Implementation

Complete example with Google Cloud services

Google Cloud Documentation

Official Google Cloud Speech-to-Text documentation

Google Cloud Console

Create service accounts and manage API access

Installation

To use Google Cloud Speech services, install the required dependency:

uv add "pipecat-ai[google]"

Prerequisites

Google Cloud Setup

Before using Google Cloud STT services, you need:

Google Cloud Account: Sign up at Google Cloud Console
Project Setup: Create a project and enable the Speech-to-Text API
Service Account: Create a service account with Speech-to-Text permissions
Authentication: Set up credentials via service account key or Application Default Credentials

Required Environment Variables

GOOGLE_APPLICATION_CREDENTIALS: Path to your service account key file (recommended)
Or use Application Default Credentials for cloud deployments

Configuration

GoogleSTTService

str

default:"None"

JSON string containing Google Cloud service account credentials.

str

default:"None"

Path to service account credentials JSON file.

str

default:"global"

Google Cloud location (e.g., "global", "us-central1"). Non-global locations use regional endpoints.

int

default:"None"

Audio sample rate in Hz. When None, uses the pipeline’s configured sample rate.

GoogleSTTService.InputParams

default:"None"

deprecated

Configuration parameters for the STT service. Deprecated in v0.0.105. Use settings=GoogleSTTService.Settings(...) instead.

GoogleSTTService.Settings

default:"None"

Runtime-configurable settings for the STT service. See Settings below.

float

default:"GOOGLE_TTFS_P99"

P99 latency from speech end to final transcript in seconds. Override for your deployment.

You must provide either credentials (JSON string), credentials_path (file path), or have Application Default Credentials configured. At least one authentication method is required.

Settings

Runtime-configurable settings passed via the settings constructor argument using GoogleSTTService.Settings(...). These can be updated mid-conversation with STTUpdateSettingsFrame. See Service Settings for details.

Parameter	Type	Default	Description
`model`	`str`	`"latest_long"`	Speech recognition model to use. (Inherited from base STT settings.)
`language`	`Language \| str`	`None`	Language for speech recognition. (Inherited from base STT settings.)
`languages`	`Language \| List[Language]`	`[Language.EN_US]`	Single language or list of recognition languages. First language is primary.
`use_separate_recognition_per_channel`	`bool`	`False`	Process each audio channel separately.
`enable_automatic_punctuation`	`bool`	`True`	Add punctuation to transcripts.
`enable_spoken_punctuation`	`bool`	`False`	Include spoken punctuation in transcript.
`enable_spoken_emojis`	`bool`	`False`	Include spoken emojis in transcript.
`profanity_filter`	`bool`	`False`	Filter profanity from transcript.
`enable_word_time_offsets`	`bool`	`False`	Include timing information for each word.
`enable_word_confidence`	`bool`	`False`	Include confidence scores for each word.
`enable_interim_results`	`bool`	`True`	Stream partial recognition results.
`enable_voice_activity_events`	`bool`	`False`	Detect voice activity in audio.

Usage

Basic Setup

from pipecat.services.google.stt import GoogleSTTService

stt = GoogleSTTService(
    credentials_path=os.getenv("GOOGLE_APPLICATION_CREDENTIALS"),
)

With Credentials JSON String

import json
from pipecat.services.google.stt import GoogleSTTService

stt = GoogleSTTService(
    credentials=json.dumps(credentials_dict),
    location="us-central1",
)

With Custom Parameters

from pipecat.services.google.stt import GoogleSTTService
from pipecat.transcriptions.language import Language

stt = GoogleSTTService(
    credentials_path=os.getenv("GOOGLE_APPLICATION_CREDENTIALS"),
    settings=GoogleSTTService.Settings(
        languages=[Language.EN_US, Language.ES],
        model="latest_long",
        enable_automatic_punctuation=True,
        enable_word_time_offsets=True,
        enable_word_confidence=True,
    ),
)

Updating Settings at Runtime

Google STT supports dynamic settings updates via STTUpdateSettingsFrame:

from pipecat.frames.frames import STTUpdateSettingsFrame
from pipecat.transcriptions.language import Language

await worker.queue_frame(
    STTUpdateSettingsFrame(
        delta=GoogleSTTService.Settings(
            languages=[Language.FR],
            model="latest_short",
            enable_automatic_punctuation=False,
        )
    )
)

Notes

Streaming time limit: Google Cloud STT has a 5-minute streaming limit per connection. The service automatically handles stream reconnection at 4 minutes to provide seamless transcription without interruption.
Multi-language support: Pass a list of Language values to languages for multi-language recognition. The first language is the primary language.
Regional endpoints: Use the location parameter to route requests through regional endpoints (e.g., "us-central1", "europe-west1") for data residency requirements. The default "global" endpoint works for most use cases.
Stream abort on inactivity: If no audio is sent for ~10 seconds (e.g., when audio frames are blocked), Google automatically closes the stream. The service recovers by automatically reconnecting.
Authentication priority: The service checks for credentials in this order: credentials (JSON string), credentials_path (file), then Application Default Credentials.

The InputParams / params= pattern is deprecated as of v0.0.105. Use Settings / settings= instead. See the Service Settings guide for migration details.

Event Handlers

Google STT supports the standard service connection events:

Event	Description
`on_connected`	Connected to Google Cloud Speech-to-Text
`on_disconnected`	Disconnected from Google Cloud Speech-to-Text

@stt.event_handler("on_connected")
async def on_connected(service):
    print("Connected to Google STT")

Pipecat Server

Client SDKs

Pipecat Flows

Pipecat Cloud

CLI

Pipecat Context Hub

Overview

Google STT API Reference

Example Implementation

Google Cloud Documentation

Google Cloud Console

Installation

Prerequisites

Google Cloud Setup

Required Environment Variables

Configuration

GoogleSTTService

Settings

Usage

Basic Setup

With Credentials JSON String

With Custom Parameters

Updating Settings at Runtime

Notes

Event Handlers

​Overview

Google STT API Reference

Example Implementation

Google Cloud Documentation

Google Cloud Console

​Installation

​Prerequisites

​Google Cloud Setup

​Required Environment Variables

​Configuration

​GoogleSTTService

​Settings

​Usage

​Basic Setup

​With Credentials JSON String

​With Custom Parameters

​Updating Settings at Runtime

​Notes

​Event Handlers

Overview

Installation

Prerequisites

Google Cloud Setup

Required Environment Variables

Configuration

GoogleSTTService

Settings

Usage

Basic Setup

With Credentials JSON String

With Custom Parameters

Updating Settings at Runtime

Notes

Event Handlers