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Key Features

Overview: Ultravox Realtime

X-API-Key

Ultradox

Understanding the core concepts and architecture of Ultravox Realtime

How Ultravox Works

A guide to prompting for great voice AI experiences

Prompting Guide

Scaling & Call Concurrency

Connect with our community and get support for building voice AI agents

Getting Help

Create consistent, reusable voice AI experience with agents or direct call configuration.

Overview: Agents & Calls

Create and manage reusable voice assistant templates for consistent experiences.

Building & Editing Agents

Start conversations using agents or direct call configuration.

Making Calls

Retrieve call information, from active conversation monitoring to historical data analysis and cleanup.

Call Management

A guide to steering your agent toward good experiences

Guiding Agents

Create dynamic, multi-stage conversations.

Call Stages

Monitor, troubleshoot, and optimize your voice conversations for production quality.

Testing & Debugging

Connect Ultravox to traditional phone networks for AI-powered voice calls.

Overview: Telephony

Comprehensive guide to telephony providers that integrate with Ultravox.

Supported Providers

Configure AI agents to make outbound phone calls to users.

Outbound Calls

Configure AI agents to answer incoming phone calls.

Inbound Calls

Transfer calls between AI agents and human operators.

Call Transfers

Build interactive voice response systems with keypad input and DTMF tones.

Handling IVR Flows

Create incoming & outgoing SIP calls with Ultravox agents.

SIP Guide (PREVIEW)

Add conversational voice AI to any application - from web and mobile apps to custom server integrations using WebSockets.

Overview: Using Ultravox in Apps or via WebSockets.

Ultravox Client SDK for building user-facing experiences.

SDKs

Integrate with your server via direct WebSocket connections.

WebSocket Integration

Protocol documentation for messages exchanged between client and server during Ultravox calls.

Protocol & Data Messages

Give your agents additional capabilities while maintaining a natural conversation flow.

Overview: Tools

Ready-to-use tools for common functionality in voice applications.

Built-in Tools

Handle long-running operations and optimize tool performance for real-time conversations.

Async Tools

Voice options available in Ultravox Realtime

Overview: Voices

Voice Cloning

How to use Ultravox with your own text-to-speech provider

Bring Your Own (Key)

Learn how webhooks work with Ultravox and get started with real-time notifications.

Overview: Webhooks

Complete reference of all webhook events available in Ultravox.

Available Webhooks

Understand how Ultravox automatically retries failed webhook deliveries with exponential backoff to ensure reliable event notifications.

Error Handling & Retries

Learn how to verify webhook authenticity and protect your endpoints from malicious requests.

Securing Webhooks

Learn how Ultravox intelligently handles voice activity detection and background noise to create natural, responsive conversations.

Overview: Noise & VAD

Learn how Ultravox's multi-model VAD system works and when to adjust voice activity detection parameters.

Understanding VAD

Built-in robust noise handling to keep your calls on track and fast.

Handling Background Noise

Built-in filtering to focus on the primary speaker in multi-speaker environments.

Handling Background Speakers

Ultravox REST API Overview

Returns account details for a single account

Get Account

Returns aggregated and per-day call usage data

Get Call Usage

Allows adding or updating TTS provider API keys to an account, enabling ExternalVoices

Set TTS API keys

Returns the TTS provider API keys associated with the active account

Get Account TTS API Keys

List Agents

Creates a new agent using the specified name and call template

Create Agent

Get Agent

Update Agent

Delete Agent

Lists all calls that were created using the specified agent

List Agent Calls

Creates a new call using the the specified agent

Create Agent Call

Calls Overview

List Calls

Get Call

Creates a new call using the specified system prompt and other properties

Create Call

Delete Call

Returns all messages generated during the given call

List Call Messages

Returns all tools that were available at any point during the call

List Call Tools

Returns a link to the recording of the call

Get Call Recording

Lists all stages that occurred during the specified call

List Call Stages

Retrieves details for a specific stage of a call

Get Call Stage

Returns all messages that were exchanged during a specific stage of a call

List Call Stage Messages

Returns all tools that were available during a specific stage of a call

List Call Stage Tools

Get Call Stage Message Audio

List Deleted Calls

Gets details for the specified deleted call

Get Deleted Call

Returns any events logged during the call

List Call Events

Understanding Retrieval Augmented Generation in Ultravox

Corpus Service (RAG) Overview

List Corpora

Creates a new corpus using the specified name and description

Create Corpus

Get Corpus

Update Corpus

Delete Corpus

Queries the specified corpus and returns the specified number of results

Query Corpus

Lists all sources that are part of the specified corpus

List Corpus Sources

Creates a new source for the specified corpus

Create Corpus Source

Retrieves details for the specified source

Get Corpus Source

Update Corpus Source

Delete Corpus Source

Returns details for all documents contained in the source

List Corpus Source Documents

Retrieves details for the specified source document

Get Corpus Source Document

Creates a new URL and document ID to use for uploading a static file

Create Corpus File Upload

List Tools

Get Tool

Create Tool

Update Tool

Delete Tool

Gets all calls that have used the specified tool

Get Tool History

List Voices

Get Voice

Create (Clone) Voice

Delete Voice

Retrieves all webhooks configured on an account

List Webhooks

Gets details for the specified webhook configuration

Get Webhook

Creates a new webhook configuration for an account

Create Webhook

Replaces the specified webhook configuration

Replace Webhook

Updates the specified webhook configuration

Update Webhook

Deletes the specified webhook configuration

Delete Webhook

Call Definition

Base Tool Definition

Ultravox Data Message Protocol

Retrieves the list of all available models that can be used for inference

List Models

Gets the OpenAPI schema for the Ultravox REST API

Get OpenAPI Schema

Ultravox Client SDK

Connecting Ultravox to SIP Using Voximplant

Voximplant

Stay informed about Ultravox platform announcements.

News & Updates

Track upcoming breaking changes, migration timelines, and deprecation notices for the Ultravox platform.

Deprecation Guide

Ultravox Realtime

Key concepts to understand before building a voice AI agent.

It's All Prompting

There is no ASR

Tools are Just Functions

The Start Call 2-Step

Ultravox Realtime is Fast and Cheap

Prompting Quickstart

Connect outoing Twilio calls to an Ultravox agent in 5 minutes or less.

Outgoing Phone Calls

Connect incoming calls to an AI agent in 6 minutes.

Incoming Phone Calls

Build and Deploy an Agent to the Browser in 5 Minutes

Web Quickstart

Creating an API Key

Using Tools

Give you agent access to product documents, KBs, and more.

Adding Knowledge (RAG)

Use Ultravox to make and receive calls using WebRTC, via Telnyx, Twilio, Plivo, or jambonz.

Getting Started

Agents & Calls

Telephony

Web, Apps, Websockets

Tools

Voices

Webhooks

Noise & VAD

Overview: Ultravox Realtime

Sign-up

Quickstart

API Reference + Playground

Key Features

Getting Started

Agents & Calls

Telephony

Web, Apps, Websockets

Tools

Voices

Webhooks

Noise & VAD

Sign-up

Quickstart

API Reference + Playground

​Key Features

Key Features