AssemblyAI plugin guide

Available in

Python

Overview

This plugin allows you to use AssemblyAI as an STT provider for your voice agents.

LiveKit Inference

AssemblyAI is also available in LiveKit Inference, with billing and integration handled automatically. See the docs for more information.

Quick reference

This section provides a brief overview of the AssemblyAI STT plugin. For more information, see Additional resources.

Installation

Install the plugin from PyPI:

uv add "livekit-agents[assemblyai]~=1.2"

Authentication

The AssemblyAI plugin requires an AssemblyAI API key.

Set ASSEMBLYAI_API_KEY in your .env file.

Usage

Use AssemblyAI STT in an AgentSession or as a standalone transcription service. For example, you can use this STT in the Voice AI quickstart.

from livekit.plugins import assemblyai

session = AgentSession(
    stt = assemblyai.STT(),
    # ... vad, llm, tts, etc.
)

Parameters

This section describes some of the available parameters. See the plugin reference for a complete list of all available parameters.

format_turnsboolOptionalDefault: True

Whether to return formatted final transcripts. If enabled, formatted final transcripts are emitted shortly following an end-of-turn detection.

end_of_turn_confidence_thresholdfloatOptionalDefault: 0.7

The confidence threshold to use when determining if the end of a turn has been reached.

min_end_of_turn_silence_when_confidentintOptionalDefault: 160

The minimum duration of silence required to detect end of turn when confident.

max_turn_silenceintOptionalDefault: 2400

The maximum duration of silence allowed in a turn before end of turn is triggered.

Turn detection

AssemblyAI includes a custom phrase endpointing model that uses both audio and linguistic information to detect turn boundaries. To use this model for turn detection, set turn_detection="stt" in the AgentSession constructor. You should also provide a VAD plugin for responsive interruption handling.

session = AgentSession(
    turn_detection="stt",
    stt=assemblyai.STT(
      end_of_turn_confidence_threshold=0.7,
      min_end_of_turn_silence_when_confident=160,
      max_turn_silence=2400,
    ),
    vad=silero.VAD.load(), # Recommended for responsive interruption handling
    # ... llm, tts, etc.
)

Additional resources

The following resources provide more information about using AssemblyAI with LiveKit Agents.

Python package

The livekit-plugins-assemblyai package on PyPI.

Plugin reference

Reference for the AssemblyAI STT plugin.

GitHub repo

View the source or contribute to the LiveKit AssemblyAI STT plugin.

AssemblyAI docs

AssemblyAI's full docs for the Universal Streaming API.

Voice AI quickstart

Get started with LiveKit Agents and AssemblyAI.

AssemblyAI LiveKit guide

Guide to using AssemblyAI Universal Streaming STT with LiveKit.