A framework for building real-time, voice-enabled AI agents — combining STT, LLM reasoning, and TTS into a low-latency conversational pipeline over WebRTC.
LiveKit Agents is a Python framework (part of the LiveKit open-source ecosystem) for building real-time AI agents that communicate over voice and video. It handles the full pipeline: speech-to-text (STT), LLM reasoning, text-to-speech (TTS), and the WebRTC transport layer. The framework manages turn-taking, interruptions, and streaming so you can focus on the agent logic.
A voice agent pipeline: (1) Audio input arrives over WebRTC. (2) VAD (voice activity detection) detects speech start/end. (3) STT converts audio to text in real-time (streaming). (4) LLM generates a response to the transcribed input. (5) TTS converts the response text to audio. (6) Audio is streamed back to the caller. Each stage runs in parallel with the next where possible to minimise latency.
from livekit.agents import AutoSubscribe, JobContext, WorkerOptions, cli, llm
from livekit.agents.voice_assistant import VoiceAssistant
from livekit.plugins import deepgram, openai, silero
async def entrypoint(ctx: JobContext):
await ctx.connect(auto_subscribe=AutoSubscribe.AUDIO_ONLY)
initial_ctx = llm.ChatContext().append(
role="system",
text="You are a helpful voice assistant. Keep responses concise and conversational.",
)
assistant = VoiceAssistant(
vad=silero.VAD.load(),
stt=deepgram.STT(),
llm=openai.LLM(model="gpt-4o-mini"),
tts=openai.TTS(voice="alloy"),
chat_ctx=initial_ctx,
)
assistant.start(ctx.room)
await assistant.say("Hello! How can I help you today?", allow_interruptions=True)
if __name__ == "__main__":
cli.run_app(WorkerOptions(entrypoint_fnc=entrypoint))LiveKit Agents handles barge-in (user interrupts the agent mid-speech): when VAD detects the user speaking while the agent is talking, the agent stops, the current TTS output is discarded, and the user's new utterance is processed. This makes conversations feel natural rather than stilted. The framework also handles silence detection to know when the user has finished speaking.
STT: Deepgram (recommended, low latency), OpenAI Whisper, AssemblyAI, Google STT. LLM: OpenAI GPT-4o-mini (low latency), Anthropic Claude, local models via Ollama. TTS: OpenAI TTS, ElevenLabs, Cartesia, Deepgram TTS. For lowest latency: Deepgram STT + GPT-4o-mini + Cartesia TTS achieves ~500 ms round-trip.
Deploy LiveKit Agents as worker processes that connect to a LiveKit server (cloud or self-hosted). The server handles WebRTC signalling and media routing; agents handle the AI logic. Scale by running multiple worker processes — the server distributes incoming calls. LiveKit Cloud offers managed infrastructure; self-hosted via the open-source LiveKit server.
This section covers advanced patterns and implementation considerations for production environments. Understanding these concepts ensures robust and scalable deployments.
// Publishing a local video stream
const localParticipant = room.localParticipant;
const videoTrack = await createLocalVideoTrack({
resolution: { width: 1280, height: 720 },
aspectRatio: 16 / 9
});
localParticipant.publishTrack(videoTrack);| Criteria | Description | Consideration |
|---|---|---|
| Performance | Latency and throughput metrics | Measure against baselines |
| Scalability | Horizontal and vertical scaling | Plan for growth |
| Integration | Compatibility with ecosystem | Reduce friction |
| Cost | Operational and infrastructure costs | Total cost of ownership |
Understanding the fundamentals enables practitioners to make informed decisions about tool selection and implementation strategy. These foundational concepts shape how systems are architected and operated in production environments.
Production deployments require careful consideration of operational characteristics including resource consumption, latency profiles, and failure modes. Comprehensive testing against real-world scenarios helps validate assumptions and identify edge cases.
Community adoption and ecosystem maturity directly impact long-term viability. Active maintenance, thorough documentation, and responsive support channels significantly reduce implementation friction and maintenance burden.
Cost considerations extend beyond initial implementation to include ongoing operational expenses, training requirements, and opportunity costs of technology choices. A holistic cost analysis accounts for both direct and indirect expenses over the system lifetime.
Integration patterns and interoperability with existing infrastructure determine deployment success. Compatibility layers, standardized interfaces, and clear migration paths smooth the adoption process for teams with legacy systems.
Monitoring and observability are critical aspects of production systems. Establishing comprehensive metrics, logging, and alerting mechanisms enables rapid detection and resolution of issues before they impact end users.
Understanding the fundamentals enables practitioners to make informed decisions about tool selection and implementation strategy. These foundational concepts shape how systems are architected and operated in production environments. Key considerations include performance characteristics, resource utilization patterns, and integration requirements that vary significantly based on specific use cases and organizational constraints.
Production deployments require careful consideration of operational characteristics including resource consumption, latency profiles, failure modes, and recovery mechanisms. Comprehensive testing against real-world scenarios helps validate assumptions, identify edge cases, and stress-test systems under realistic conditions. Automation of testing pipelines ensures consistent quality and reduces manual effort during deployment cycles.
Community adoption and ecosystem maturity directly impact long-term viability and maintenance burden. Active development communities, thorough documentation, responsive support channels, and regular updates significantly reduce implementation friction. The availability of third-party integrations, plugins, and extensions extends functionality and accelerates time-to-value for organizations adopting these technologies.
Cost considerations extend beyond initial implementation to include ongoing operational expenses, training requirements, infrastructure costs, and opportunity costs of technology choices. A holistic cost analysis accounts for both direct expenses and indirect costs spanning acquisition, deployment, operational overhead, and eventual maintenance or replacement. Return on investment calculations must consider these multifaceted dimensions.
Integration patterns and interoperability with existing infrastructure determine deployment success and organizational impact. Compatibility layers, standardized interfaces, clear migration paths, and backward compatibility mechanisms smooth adoption for teams managing legacy systems. Understanding integration points and potential bottlenecks helps avoid common pitfalls and ensures smooth operational transitions.
Monitoring and observability are critical aspects of modern production systems and operational excellence. Establishing comprehensive metrics, structured logging, distributed tracing, and alerting mechanisms enables rapid detection and resolution of issues before they impact end users. Instrumentation at multiple layers provides visibility into system behavior and helps drive continuous improvements.
Security considerations span multiple dimensions including authentication, authorization, encryption, data protection, and compliance with regulatory frameworks. Implementing defense-in-depth strategies with multiple layers of security controls reduces risk exposure. Regular security audits, penetration testing, and vulnerability assessments help identify and remediate weaknesses proactively before they become exploitable.
Scalability architecture decisions influence system behavior under load and determine capacity for future growth. Horizontal and vertical scaling approaches present different tradeoffs in terms of complexity, cost, and operational overhead. Designing systems with scalability in mind from inception prevents costly refactoring and ensures smooth expansion as demand increases.
Understanding the fundamentals enables practitioners to make informed decisions about tool selection and implementation strategy. These foundational concepts shape how systems are architected and operated in production environments. Key considerations include performance characteristics, resource utilization patterns, and integration requirements that vary significantly based on specific use cases and organizational constraints.
Production deployments require careful consideration of operational characteristics including resource consumption, latency profiles, failure modes, and recovery mechanisms. Comprehensive testing against real-world scenarios helps validate assumptions, identify edge cases, and stress-test systems under realistic conditions. Automation of testing pipelines ensures consistent quality and reduces manual effort during deployment cycles.
Community adoption and ecosystem maturity directly impact long-term viability and maintenance burden. Active development communities, thorough documentation, responsive support channels, and regular updates significantly reduce implementation friction. The availability of third-party integrations, plugins, and extensions extends functionality and accelerates time-to-value for organizations adopting these technologies.
Cost considerations extend beyond initial implementation to include ongoing operational expenses, training requirements, infrastructure costs, and opportunity costs of technology choices. A holistic cost analysis accounts for both direct expenses and indirect costs spanning acquisition, deployment, operational overhead, and eventual maintenance or replacement. Return on investment calculations must consider these multifaceted dimensions.
Integration patterns and interoperability with existing infrastructure determine deployment success and organizational impact. Compatibility layers, standardized interfaces, clear migration paths, and backward compatibility mechanisms smooth adoption for teams managing legacy systems. Understanding integration points and potential bottlenecks helps avoid common pitfalls and ensures smooth operational transitions.
Monitoring and observability are critical aspects of modern production systems and operational excellence. Establishing comprehensive metrics, structured logging, distributed tracing, and alerting mechanisms enables rapid detection and resolution of issues before they impact end users. Instrumentation at multiple layers provides visibility into system behavior and helps drive continuous improvements.
Security considerations span multiple dimensions including authentication, authorization, encryption, data protection, and compliance with regulatory frameworks. Implementing defense-in-depth strategies with multiple layers of security controls reduces risk exposure. Regular security audits, penetration testing, and vulnerability assessments help identify and remediate weaknesses proactively before they become exploitable.