SmallWebRTCTransport

A lightweight WebRTC transport for peer-to-peer audio and video communication in Pipecat

Overview

SmallWebRTCTransport enables peer-to-peer (“serverless”) WebRTC connections between clients and your Pipecat application. It implements bidirectional audio, video and data channels using WebRTC for real-time communication. This transport is open source and self-contained, with no dependencies on any other infrastructure.

For detailed notes on how to decide between using the SmallWebRTCTransport or other WebRTC transports like the DailyTransport, see this post.

SmallWebRTC Transport API Reference

Transport methods and configuration options

SmallWebRTC Connection API Reference

Connection management and signaling methods

Example Implementation

Complete peer-to-peer voice agent example

WebRTC Documentation

Official WebRTC protocol documentation

Installation

To use SmallWebRTCTransport, install the required dependencies:

pip install "pipecat-ai[webrtc]"

Prerequisites

WebRTC Application Setup

Before using SmallWebRTCTransport, you need:

1. Signaling Server: Implement WebRTC offer/answer exchange (required)
2. Client Implementation: Set up WebRTC client for browser or application use
3. ICE Configuration: Configure STUN/TURN servers for NAT traversal (optional for local networks)
4. Development Runner: Use Pipecat’s development runner for quick setup (recommended)

No API keys are required since this is a peer-to-peer transport implementation. For production deployments across different networks, you may need to configure STUN/TURN servers for NAT traversal.

Configuration Options

• Development Runner: Automatic server infrastructure and web interface (recommended)
• Manual Implementation: Custom signaling server for advanced use cases
• ICE Servers: STUN/TURN configuration for network traversal
• Media Configuration: Audio/video parameters and format handling

Key Features

• Serverless Architecture: Direct peer-to-peer connections with no intermediate servers
• Production Ready: Heavily tested and used in Pipecat examples
• Bidirectional Media: Full-duplex audio and video streaming
• Data Channels: Application messaging and signaling support
• Development Tools: Built-in development runner with web interface

Configuration

SmallWebRTCTransport

webrtc_connection · SmallWebRTCConnection · required

The underlying WebRTC connection handler that manages signaling and peer connections.

params · TransportParams · required

Transport configuration parameters for audio, video, and VAD settings.

input_name · str · default: "None"

Optional name for the input transport processor.

output_name · str · default: "None"

Optional name for the output transport processor.

Usage

SmallWebRTCTransport requires both a signaling server for WebRTC handshake and your Pipecat bot implementation. The easiest approach is using Pipecat’s development runner which handles all server infrastructure automatically.

See the complete examples for full implementations including:

• Development runner setup with automatic web interface
• Manual signaling server implementation
• WebRTC client integration
• ICE server configuration for production deployment

Event Handlers

SmallWebRTCTransport provides event handlers for client connection lifecycle and application messaging. Register handlers using the @event_handler decorator on the transport instance.

Events Summary

Event	Description
on_client_connected	Client WebRTC connection established
on_client_disconnected	Client WebRTC connection closed
on_app_message	App message received from client

Connection Lifecycle

on_client_connected

Fired when a client establishes a WebRTC peer connection.

@transport.event_handler("on_client_connected")
async def on_client_connected(transport, webrtc_connection):
    print("Client connected")

Parameters:

Parameter	Type	Description
transport	SmallWebRTCTransport	The transport instance
webrtc_connection	SmallWebRTCConnection	The WebRTC connection object

on_client_disconnected

Fired when a client’s WebRTC peer connection is closed.

@transport.event_handler("on_client_disconnected")
async def on_client_disconnected(transport, webrtc_connection):
    print("Client disconnected")

Parameters:

Parameter	Type	Description
transport	SmallWebRTCTransport	The transport instance
webrtc_connection	SmallWebRTCConnection	The WebRTC connection object

Messaging

on_app_message

Fired when an application message is received from a client through the WebRTC data channel.

@transport.event_handler("on_app_message")
async def on_app_message(transport, message, sender):
    print(f"Message from {sender}: {message}")

Parameters:

Parameter	Type	Description
transport	SmallWebRTCTransport	The transport instance
message	Any	The message content
sender	str	The sender’s peer connection ID

Additional Resources

• Events Overview - Overview of all events in Pipecat
• Pipecat Development Runner’s Transport Utilities
• Client SDK Integration