Ultravox review

Ultravox builds its own speech model rather than chaining separate transcription and LLM steps, and publishes the weights on Hugging Face. Its pricing is the plainest here: the first 30 minutes are free, then $0.05 per minute with text-to-speech included, SIP at half a cent per minute, and no surge pricing. Pay as you go allows 5 concurrent calls, one custom voice and two RAG corpora; Pro, at $100 a month on the annual rate, removes the hard concurrency cap and adds an outbound call scheduler, five voices and 20 corpora. Developers work through REST APIs and SDKs for web and mobile, with built-in links to major telephony providers. The UltraVAD model handles turn-taking. Ultravox has been acquired by Inworld, which the site says will speed up its speech-to-speech work, but buyers should watch for plan changes. The low concurrency cap makes pay as you go a test tier for anything beyond small lines.

Who it is for

Developers who want a speech-native model and a flat per-minute rate through a REST API and SDKs.

Price

Pay as you go: first 30 minutes free, then $0.05 per minute including TTS; Pro $100 per month billed yearly.

First 30 minutes free, $0.05/min after that.
Quoted from the vendor pricing page on November 7, 2026.

Key features

• Ultravox v0.7 speech model with open weights on Hugging Face
• UltraVAD neural model for turn-taking
• REST APIs and SDKs for web and mobile
• RAG corpora and custom voice clones
• Outbound call scheduler on Pro

Strengths and weaknesses

• Strength: Flat $0.05 per minute that includes text-to-speech
• Strength: No surge pricing on any plan
• Strength: 30 free minutes and unlimited playground calls
• Weakness: Pay as you go has a hard cap of 5 concurrent calls
• Weakness: Pro costs $100 per month at the annual rate to lift caps
• Weakness: Acquired by Inworld, so the roadmap may change

Key facts

• Free minutes: 30
• SIP: $0.005 per minute on pay as you go
• Concurrency: 5 on pay as you go, no hard cap on Pro

Where it ranks

Ultravox is No. 7 in our Best AI Voice Agent Platforms verdict.