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LiveKit Agents API Documentation

Overview

A production-ready backend for building and operating real-time voice AI agents with LiveKit, OpenAI, and SIP telephony integration.

Get Started API Reference

What You Can Build

  • Outbound SIP calls — dial a phone number, connect an AI assistant, receive a webhook when the call ends
  • Inbound SIP calls — map a phone number to an assistant; incoming calls are routed automatically
  • Web calls — embed a voice/chat widget in any browser or mobile app, no SIP required
  • Caller-context enrichment — fetch live CRM or ticket data before the assistant speaks on inbound calls

Key Concepts

Concept Description
Assistant Defines the agent's behavior: system prompt, TTS voice (cartesia, sarvam, elevenlabs, mistral), interaction settings, and optional end-call tool
Tool Extends assistant capabilities with webhook calls or static-return actions during a conversation
SIP Trunk Stores your telephony provider credentials (Twilio or Exotel) for outbound dialing
Inbound Mapping Links a phone number to an assistant for inbound call routing
Inbound Context Strategy Optionally fetches caller-specific data (CRM, tickets) before prompt rendering on inbound calls

Supported Providers

Provider Inbound Outbound Integration
Twilio Not yet Supported LiveKit managed SIP
Exotel Supported Supported Custom SIP bridge
Web (WebRTC) — Supported Browser/mobile, no SIP

Platform Architecture

graph TD
    Client[Client Application] -->|REST API| API[API Server\nFastAPI]
    Client -->|WebRTC| LiveKit[LiveKit Server]

    API -->|CRUD| DB[(MongoDB)]

    Worker[Agent Worker] -->|Connect| LiveKit
    Worker -->|Fetch Config| DB
    Worker -->|LLM + TTS| AI[OpenAI + TTS Providers]
    Worker -->|Webhook| External[External Services]

See Architecture for full call-flow diagrams and integration modes.

For inbound caller-context setup and APIs, see Inbound Context Strategies.