Speechmatics Real-Time API Client

Async Python client for the Speechmatics Real-Time API.

Features

• Async-first design with simpler interface
• Multi-channel transcription - Simultaneous processing of multiple audio sources
• Single-stream transcription - Optimized client for single audio source
• Comprehensive error handling with detailed error messages
• Type hints throughout for excellent IDE support and code safety
• Environment variable support for secure credential management
• Event-driven architecture for real-time transcript processing
• Simple connection management with clear error reporting

Installation

pip install speechmatics-rt

Quick Start

import asyncio
from speechmatics.rt import AsyncClient, ServerMessageType


async def main():
    # Create a client using environment variable SPEECHMATICS_API_KEY
    async with AsyncClient() as client:
        # Register event handlers
        @client.on(ServerMessageType.ADD_TRANSCRIPT)
        def handle_final_transcript(msg):
            print(f"Final: {msg['metadata']['transcript']}")

        # Transcribe audio file
        with open("audio.wav", "rb") as audio_file:
            await client.transcribe(audio_file)

# Run the async function
asyncio.run(main())

Multi-Channel Transcription

import asyncio
from speechmatics.rt import AsyncMultiChannelClient, ServerMessageType, TranscriptionConfig

async def main():
    # Prepare multiple audio sources
    sources = {
        "left": open("left.wav", "rb"),
        "right": open("right.wav", "rb"),
    }

    try:
        async with AsyncMultiChannelClient() as client:
            # Handle transcripts with channel identification
            @client.on(ServerMessageType.ADD_TRANSCRIPT)
            def handle_transcript(msg):
                channel = msg["results"][0]["channel"]
                transcript = msg["metadata"]["transcript"]
                print(f"[{channel}]: {transcript}")

            # Start multi-channel transcription
            await client.transcribe(
                sources,
                transcription_config=TranscriptionConfig(
                    language="en",
                    diarization="channel",
                    channel_diarization_labels=list(sources.keys()),
                )
            )
    finally:
        # Ensure all files are closed
        for source in sources.values():
            source.close()

asyncio.run(main())

JWT Authentication

For enhanced security, use temporary JWT tokens instead of static API keys. JWTs are short-lived (60 seconds by default).

from speechmatics.rt import AsyncClient, JWTAuth

# Create JWT auth (requires: pip install 'speechmatics-rt[jwt]')
auth = JWTAuth("your-api-key", ttl=60)

async with AsyncClient(auth=auth) as client:
    pass

Ideal for browser applications or when minimizing API key exposure. See the authentication documentation for more details.

Logging

The client supports logging with job id tracing for debugging. To increase logging verbosity, set DEBUG level in your example code:

import logging
import sys

logging.basicConfig(
    level=logging.DEBUG,
    format='%(asctime)s - %(name)s - %(levelname)s - %(message)s',
    handlers=[
        logging.StreamHandler(sys.stdout)
    ]
)

Environment Variables

The client supports the following environment variables:

• SPEECHMATICS_API_KEY: Your Speechmatics API key
• SPEECHMATICS_RT_URL: Custom API endpoint URL (optional)