Ultravox

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Ultravox is an AI Agents & Automation tool that provides a fast multimodal LLM for real-time voice interactions. It allows for building real-time Voice AI agents and can understand text as well as human speech without a separate ASR stage.

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At a glance

Pricing

Open Source

Free tier

Yes

API

Yes

Skill level

Technical

About

What is ultravox?

Ultravox is a fast multimodal LLM designed for real-time voice interactions, developed by Fixie.ai. It distinguishes itself by understanding both text and human speech directly, eliminating the need for a separate Audio Speech Recognition (ASR) stage. This direct coupling enables Ultravox to respond much more quickly than traditional systems. The model is built on research from AudioLM, SeamlessM4T, Gazelle, and SpeechGPT, extending open-weight LLMs like Llama 3, Mistral, and Gemma with a multimodal projector. It currently takes audio input and emits streaming text, with future plans to emit speech tokens for direct audio conversion. Ultravox offers an 8B variant on Hugging Face and allows for training against any open-weight model, making it highly customizable for various use cases.

Best used for

Ideal for developers and researchers who need to build real-time voice AI agents, integrate audio understanding into LLMs, and develop custom speech-to-text solutions. Especially valuable for those looking to extend open-weight LLMs with multimodal capabilities for faster, more natural voice interactions.

Common actions

build voice agents

process real-time audio

train custom LLMs

integrate speech recognition

open-sourcecollaborationworkflowsdeepfakegithub copilotface swappinglow-code/no-codeautomated workflow"AI Agents"

Capabilities

Key features

Multimodal LLM
Real-time voice interaction
No separate ASR
Supports open-weight LLMs
Customizable training
Streaming text output

Target Audience

developersai researchersvoice ai engineers

Integrations

Not yet documented

Pricing & Plans

Open Source

Free

FAQs

What LLMs can Ultravox be trained with?

Ultravox can be trained against any open-weight LLM. The default model is built on Llama 3.3 70B, and an 8B variant is available on Hugging Face. It has also been trained with Mistral and Gemma.

How does Ultravox achieve real-time voice interaction without ASR?

Ultravox uses a multimodal projector to convert audio directly into the high-dimensional space used by the LLM, bypassing the need for a separate Audio Speech Recognition (ASR) stage. This direct coupling allows for much faster responses.

Can I run Ultravox on my own infrastructure?

Yes, you can spin up an Ultravox instance on platforms like BaseTen for using your own audio content. For real-time capacity, managed APIs are offered, and the project is open-source, allowing for self-hosting and customization.

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Content & Design › Audio & Music Coding & Development › Open Source & Models

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