Ultravox
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About
Ultravox is a specialized voice AI platform designed to overcome the limitations of traditional "orchestrator" models. Unlike systems that transcribe speech to text before processing it with a Large Language Model, Ultravox uses a speech-native model. This approach allows the AI to understand paralinguistic signals such as tone, pitch, and cadence, which are typically lost in transcription. By managing the entire inference stack and purpose-built infrastructure, the platform provides a human-like conversational experience that is both fast and intelligent, avoiding the robotic feel of legacy systems. The platform features the Ultravox v0.7 model, which achieves high scores on the Big Bench Audio benchmark, reaching up to 97% accuracy with thinking enabled. Developers can integrate these capabilities using REST APIs and SDKs available for web and mobile platforms. A critical component of the stack is UltraVAD v0.1, a neural voice activity detection model that predicts turn-taking and conversation states, distinguishing between thoughtful pauses and the end of a speaker's turn. Additionally, the platform supports telephony integration, custom voice cloning, and Retrieval-Augmented Generation (RAG) through "corpora" for grounded knowledge base interactions. This tool is primarily built for software developers, product teams, and enterprises looking to build sophisticated voice interfaces. It serves industries requiring high-fidelity interaction, such as customer support automation, virtual assistants, and AI-driven telephony services. Because it offers both a "Pay As You Go" tier for experimenters and a robust "Pro" tier for scaling businesses, it accommodates everyone from solo developers building prototypes to large-scale organizations managing high-volume concurrent calls. What distinguishes Ultravox is its commitment to open science and its end-to-end infrastructure. By providing open-weight models on Hugging Face, the company fosters transparency and community improvement. Furthermore, by eliminating the need for external LLM calls or shared inference pools, Ultravox significantly reduces the latency that causes the "uncanny valley" effect in voice AI. The combination of its specialized VAD model and speech-native architecture ensures that AI agents react more like humans, responding to subtle vocal cues rather than just raw text strings.
Pros & Cons
Eliminates transcription latency by processing audio natively.
Captures paralinguistic signals like tone, cadence, and pitch.
State-of-the-art accuracy with a 91.8% score on Big Bench Audio.
Generous 30-minute free trial with no surge pricing on paid tiers.
Open-weight models are available for transparency on Hugging Face.
Pay As You Go plan is strictly limited to 5 concurrent calls.
Service Level Agreements (SLAs) are only available for Enterprise customers.
Voice generation features are currently listed as 'Coming Soon'.
Telephony/SIP usage incurs additional per-minute costs.
Use Cases
Software developers can integrate low-latency voice assistants into mobile apps using dedicated SDKs.
Customer support teams can deploy AI agents capable of outbound call scheduling and natural phone interaction.
AI researchers can utilize the open-weight Ultravox models on Hugging Face for research and development.
Enterprise businesses can scale high-concurrency voice operations with custom brand voices and RAG support.
Startups can prototype voice-native products using the free 30-minute tier and unlimited playground calls.
Platform
Features
• custom voice cloning
• outbound call scheduler
• web and mobile sdks
• rag corpora support
• telephony integration
• neural voice activity detection
• real-time rest apis
• speech-native ai model
FAQs
What makes Ultravox different from other voice AI?
Ultravox uses a speech-native model rather than transcribing audio to text first. This preserves paralinguistic cues like tone and pitch while significantly reducing latency by removing the transcription step.
How does the pricing work for calls?
The first 30 minutes are free on all plans. After that, usage is billed at a rate of $0.05 per minute, with additional small fees for SIP telephony if required.
Does Ultravox support telephony integrations?
Yes, it includes built-in integrations with major telephony providers. It also offers specific SIP pricing starting at 0.5 cents per minute.
What is the UltraVAD model?
UltraVAD is a neural voice activity detection model that recognizes when a user is likely finished speaking versus just pausing, enabling natural turn-taking in conversations.
Can I use my own knowledge base with Ultravox?
Yes, the platform supports RAG (Retrieval-Augmented Generation) through corpora. The Pay As You Go plan allows 2 corpora, while the Pro plan supports up to 20.
Pricing Plans
Pro
USD100.00 / per month• No hard caps on concurrency
• Outbound Call Scheduler
• 5 custom voices
• 20 corpora for RAG
• 0.48c per minute SIP pricing
• Everything in Pay As You Go
• Annual billing rate
Enterprise
Unknown Price• Priority SLA
• Org support
• Customizable everything
• Response SLA
• Custom minutes
• Custom voices
Pay As You Go
Free Plan• First 30 minutes free
• $0.05 per minute after
• Unlimited playground calls
• Up to 5 concurrent calls
• 1 custom voice clone
• 2 corpora for RAG
• 0.5c per minute SIP pricing
• No surge pricing
Job Opportunities
There are currently no job postings for this AI tool.
Ratings & Reviews
No ratings available yet. Be the first to rate this tool!
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