Voice Assistants

Ultravox.ai

Build real-time, conversational voice AI agents with a speech-native model that avoids slow text transcription.

ultravox.ai

Verified API available Free tier

Quick facts
What is it	Build real-time, conversational voice AI agents with a speech-native model that avoids slow text transcription.
Pricing	Freemium — from $100/mo
Free tier	Yes
Platform	Web Application
API	Yes
Best for	Building customer service voice agents for call centers, Creating conversational AI assistants for mobile apps
Domain registered	2023

Data updated Aug. 1, 2026

What does Ultravox.ai do?

Ultravox.ai is a platform for building real-time voice AI agents that converse naturally with humans. Instead of converting speech to text first like most systems, Ultravox.ai uses a speech-native model that processes audio directly. This approach preserves paralinguistic cues like tone and cadence that give human speech its nuance. The platform is designed for developers who need to create voice interfaces that feel fast and natural, not slow and robotic.

The system runs on dedicated infrastructure that Ultravox.ai manages end-to-end, which keeps latency low by avoiding shared inference pools. The core model, Ultravox v0.7, scores highly on audio intelligence benchmarks. It works with UltraVAD v0.1 for dynamic endpointing, which helps the AI understand conversation flow by recognizing when someone is finished speaking versus just pausing. Developers get REST APIs, SDKs for major platforms, and built-in telephony integrations.

This tool is for teams building voice AI at scale, particularly for customer service, interactive voice response systems, or conversational assistants in apps. The pricing starts with a free tier and scales to enterprise plans, making it accessible for both experimentation and production deployment. Ultravox.ai is built on open-weight models and shares research to advance voice AI technology broadly.

Call Answering Voice Assistants

#ai agents#api#conversational ai#real-time ai#speech-native#telephony#voice ai

Key features

What makes it stand out

Speech-native AI model processes audio directly, preserving tone and cadence for natural conversations

Dedicated infrastructure and full inference stack for low-latency, real-time responses

Developer-friendly REST APIs and SDKs for easy integration across web and mobile

Dynamic endpointing with neural VAD to predict conversation flow and turn-taking

Built-in telephony support for integration with major voice call providers

Who is Ultravox.ai for?

Who benefits most from this tool

Building customer service voice agents for call centers

Creating conversational AI assistants for mobile apps

Developing interactive voice response (IVR) systems with natural conversation flow

Pricing

Free tier available — start without a credit card

Pay as You go

Free

0.005 sip per minute
0.05 price per minute
1 custom voice clones
30 free included minutes
2 number of corpora rag
5 hard cap concurrent calls
2 threads input per 1M tokens
15 threads output per 1M tokens
30 minutes of free calls
$0.05 per minute after
No surge pricing
Unlimited playground calls
Up to 5 concurrent calls

Pro

$100.0/month

Everything in Pay as You go, plus:

0.0048 sip per minute
0.05 price per minute
30 free included minutes
No hard caps on concurrency
Outbound Call Scheduler
5 custom voices
20 corpora for RAG

Enterprise

Custom

Priority SLA
Org support
Customizable everything

Trust & presence

Domain Domain registered 2023

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