Ultravox, a Seattle-based voice AI company that originally operated under the name Fixie, has been acquired by Inworld for an undisclosed sum. The firm was established in 2022 by former executives from Google and Apple to build a speech model capable of real-time, human-like voice interactions.
In late 2023, Ultravox drew notice for its experimental project, HiSanta.ai, which allowed users to converse with AI versions of Santa Claus, Rudolph, and other North Pole figures. The platform, which used British-accented voice models, is now offline.
The startup secured $17 million in seed funding in March 2023, achieving a valuation of $51.46 million at the time, per PitchBook. Backers included Redpoint Ventures, Madrona Venture Group, Zetta Venture Partners, SignalFire, Bloomberg Beta, and Kearny Jackson. Current and former executives at Google, Amazon, and Apple also invested. Before the acquisition, Ultravox employed 10 people.
Inworld, headquartered in Mountain View, California, plans to incorporate Ultravox’s technology, particularly its ability to manage turn-taking and interruptions in voice exchanges, to enhance its real-time AI chat capabilities. The acquisition follows Inworld’s $119.8 million in total funding and a valuation of $515 million.
Ultravox’s leadership has undergone changes since its launch. Zach Koch, who previously served as CEO, now holds a vice president role at Shopify. Peter Salas, brought on in 2023, is the current chief technology officer. The founding CEO, Matt Welsh, departed two years ago and is now head of AI systems at defense company Palantir Technologies. Co-founders Hessam Bagherinezhad and Justin Uberti also left, in 2023 and 2024 respectively, and both joined OpenAI.
Inworld’s CEO, Kylan Gibbs, described the acquisition as a move to broaden its platform. The company also confirmed that Ultravox’s existing customers will transition to Inworld’s Realtime TTS-2 voice technology.