The San Francisco voice AI firm says its fine-tunable model beat OpenAI and Google on customer service benchmarks
Rime, a San Francisco enterprise voice AI company, has built Prism, a speech-to-speech model aimed at businesses where a wrong answer on a phone call actually costs something. The launch follows a fundraising haul that the company’s announcement on X puts at $35 million.
Prism was unveiled on October 28, 2026. Rime describes it as the first fine-tunable speech-to-speech model built specifically for enterprises.
Speech-to-speech, or S2S, means the model takes in audio and produces audio, without the traditional relay race of separate transcription, reasoning, and voice systems.
The twist is a checkpoint in the middle. Before Prism speaks, it generates a text output that can be verified. That gives companies a written record of what the model intends to say before a customer hears it.
Prism can also be fine-tuned on a client’s own data. Companies can deploy it in a private cloud or fully on-premises, which addresses the compliance and security demands that keep many regulated firms away from public AI services.
The numbers Rime is pointing to
Speed is the first selling point. Prism responds to the first audio input in roughly 500 to 570 milliseconds, around half a second.
On the τ-Voice benchmark, which simulates customer service interactions, Prism scored 56.6. Rime says that result put it ahead of real-time models from OpenAI and Google.
In a trial with Revmo, Prism completed order placement 94% of the time after securing the caller’s consent. An OpenAI model in the same comparison managed 57%.
The trial also showed 100% order confirmations and 85% of calls free of hallucinations. Rime says those rates improved on what previous models delivered.
Who is behind it, and who is paying
Rime was founded by CEO Lily Clifford, Brooke Larson, a linguist who previously worked on Amazon’s Alexa, and Ares Geovanis, an engineer with Stanford and UCSF experience.
The company already handles a sizable volume of voice traffic. Rime powers nearly 100 million phone calls each month for clients across several industries.
Its customer list includes major enterprises such as the Mayo Clinic and Dialpad. The company is targeting healthcare, finance, airlines, and food service.
On the funding side, Rime closed a $24 million Series A in July 2026. That round followed an earlier $5.5 million seed round. Those publicly detailed rounds account for approximately $29.5 to $32.6 million in total funding, while the announcement on X cites a $35 million raise.
