09.30.2026
We have acquired Ultravox to Advance Realtime Voice AI
Summarize with:
Inworld has acquired Ultravox, the platform developers use to build real-time voice agents. Ultravox team members who have joined Inworld will continue developing the platform.
We've worked closely with Ultravox through our text-to-speech partnership, sharing a focus on delivering Realtime AI at scale. Through that work, we saw how our technologies complement each other, and how bringing them together could help developers build better voice experiences.
Why we're coming together
Ultravox brings experience in speech understanding, reasoning, and task completion, alongside tools for managing turn-taking and interruptions in live conversations. Inworld brings top-of-benchmarks speech models (Realtime TTS-2 and Realtime STT-1), model serving, and real-time inference infrastructure for consumer-facing AI applications. Together, we can improve the full conversation: understanding what a user says, helping them accomplish a task, and responding in a voice that fits the moment.
For developers, this means better speech-to-speech experiences ahead through Inworld, alongside continued improvements to the voices and capabilities available on Ultravox. The first improvement is available today.
“I'm incredibly proud of what the Ultravox team built: real-time voice AI that customers depend on every day. When we partnered with Inworld on text-to-speech, we saw a team that moves fast and shares our commitment to delivering real-time AI at scale. I believe Inworld is the right home for Ultravox and the right team to take it further.”
Zach Koch · Co-founder and former CEO, Ultravox
What you get today
Built-in Inworld voices on Ultravox now run on Realtime TTS-2. If your agent already uses one of these voices, the upgrade is in place. Your existing voice IDs continue to work, with no code changes required. TTS-2 is a top-ranked voice model on Artificial Analysis.
More control over how your agent speaks. TTS-2 introduces natural-language steering, giving developers control over an agent's pace, tone, and emotional delivery. You can ask a voice to slow down when explaining a complicated step, sound warmer when reassuring a customer, or bring more energy to a character, all through inline instructions.
That control helps developers shape how an agent speaks around the conversation it's having. The speaker identity stays the same, though pacing and intonation may differ with the updated model. Steering is optional, so you can introduce it where it helps your application.
“At Equal AI, we're building a personal AI for aspiring Indians that knows you, speaks your language, and helps manage your calls every day. We were already working with Inworld's voice technology before the acquisition, so we're excited to see Inworld's voices and the Ultravox platform come together. Bringing them under one roof is a natural next step for the voice experiences we're building for our customers.”
Akhilesh Damaraju · CEO, Equal AI
What this means for existing Ultravox customers
Your agents keep running as usual. There is no migration or code change required as part of this announcement, and the TTS-2 upgrade comes at no additional cost. If you use a voice from another provider, nothing changes today.
You can continue using Ultravox through your existing account, with continued support from Inworld and members of the team who built the platform. For questions about your account or agents, reach us at support@inworld.ai.
What we're working on next
This acquisition advances our work on speech-to-speech experiences that bring speech understanding, reasoning, and expressive voice generation closer together. We'll share more about those capabilities and further improvements for Ultravox customers in the coming weeks.