Inworld TTS 1.5 Voices Are Now Available in Ultravox Realtime

There’s no such thing as “one-size-fits-all” when it comes to voice agents. Accent, tone, and expressiveness can make or break the end user experience, but the “right” choice depends entirely on the product you’re building. That’s why we’re excited to announce that Ultravox Realtime now allows users to build natural, conversational voice agent experiences using pre-built and custom voices using Inworld TTS 1.5. 

Emotionally expressive voices are the perfect complement to Ultravox’s best-in-class conversational voice AI, which is why we’ve teamed up with our friends at Inworld. Agents can now be configured to use any of Inworld’s pre-built voices in 15 languages; existing Inworld users who have created custom voice clones can also opt to assign a cloned voice to an Ultravox agent.

Try Inworld voices on Ultravox

To get started, simply log in to your existing Ultravox account (or create a new account).  

You can browse a list of all available Inworld voices and listen to sample audio by navigating to the Voices screen, where you can filter the list of available voices by language, provider, or both.

Once you’ve settled on a voice you like, you can either add it to an existing agent or create a new agent and select your preferred voice in the Agents screen.

Earn up to $100 in Ultravox Credits

To celebrate the launch of Inworld TTS 1.5, we’re giving away up to $100 in promotional credits for all our customers who run production voice agents with Inworld voices. 

How to qualify

1. Use Inworld voices for at least 60 call minutes during the promotion period: January 21 - February 28, 2026

2. Submit the usage survey form before March 13, 2026

3. Retain (do not delete) any eligible call records before April 1, 2026

4. For every 60 minutes of call time using Inworld voices during the promotional period, you’ll earn $1.00 in Ultravox account credits – up to $100!

All Ultravox customers (new and existing) on any paid or pay-as-you-go plan are eligible to participate, and there’s no cap on the number of customers who can take part in this promotion. 

For more information and FAQ, please visit this page. 

In our mission to deliver the best all-around conversational experience, Ultravox trained the world’s most advanced speech understanding model, capable of understanding real-world speech with no text transcription required. And Ultravox outperforms other speech-to-speech models in benchmarks that account for real-world requirements: accurate tool calling, reliable instruction following, and consistent low latency. If you haven’t given Ultravox a try yet, you can create your account here.