Rime, a San Francisco voice AI startup, just raised $24 million in Series A funding to build artificial intelligence voices designed specifically for enterprise phone calls, not chatbots or audiobooks. The company now processes over 100 million phone conversations monthly for more than 20 enterprise customers, competing directly against well-funded rivals like ElevenLabs and Deepgram.

What Makes Rime Different From Other Voice AI Companies?

Most voice AI platforms try to be everything: customer service, audiobook narration, video game characters, voice cloning. Rime is betting that phone calls deserve their own specialized technology stack. The company was founded in 2022 by Lily Clifford, a computational linguistics PhD student from Stanford; Brooke Larson, a former Amazon Alexa engineer; and Ares Geovanos, who previously built brain-computer interfaces for patients who lost the ability to speak.

That background matters. A call center voice model has to survive bad phone lines, cross talk, and background noise. A quiet lab demo doesn't face those challenges. Rime's founders spent years thinking about what makes a voice sound human under real-world pressure, not just intelligible in a controlled environment.

The company built a recording studio in San Francisco to collect conversational data from real people talking naturally with friends and family, rather than relying on voice actors reading polished scripts. This approach produces what Rime calls "working audio" instead of "showroom audio," which is exactly what a restaurant chain needs when a caller is in a car, kitchen, or noisy room.

How Does Rime's Technology Actually Work on Live Calls?

• Speech-to-Speech Models: Rime is shifting away from the traditional pipeline of separate speech-to-text, language model, and text-to-speech components. Instead, it is developing speech-to-speech models that reduce latency, improve turn-taking between human and machine, and handle background noise more effectively.
• Phoneme-Based Architecture: The company uses a phoneme-based system to adapt to different pronunciations, so customers don't have to retrain models for their specific industry or brand terminology.
• Real-World Performance: Rime's models are tuned to nail the pronunciation of different brand entities and industry-specific terms, which is critical when a customer mumbles through a bad connection.

The speed of response matters enormously. An arXiv technical tutorial published in March 2026 described the current industry pattern as a streaming pipeline where each stage passes output along instead of waiting for the whole answer to finish. Pause too long and the caller knows something is wrong.

Which Companies Are Already Using Rime's Voice AI?

Rime's customer base spans multiple industries. The company claims customers in food service, healthcare, airlines, and fintech, with enterprise contracts from clients including Mayo Clinic, Dialpad, Upstart, and Asurion. The most visible use case is pizza ordering. Business Insider reported in May 2025 that Rime's text-to-speech technology was being used by Domino's and Wingstop for phone ordering, with Domino's using the feature in approximately 80 percent of its North American phone orders.

The reason customers stayed on the line at Domino's reveals something important about Rime's design philosophy. Clifford told Business Insider the voice should sound like someone who could work at Domino's, not a 20th-century radio announcer. People don't call a pizza shop looking for emotional range. They want the order right, the menu item pronounced correctly, and the call over quickly.

"The voice technology is still not there to automate the vast majority of enterprise phone calls. LLMs have made it a lot easier to build voice applications that work, but they haven't changed how it feels to interact. Talking with a voice AI agent is not the most compelling experience for the end user. It's kinda like a new IVR, but with a better voice," said Lily Clifford, founder of Rime.

Lily Clifford, Founder, Rime

How Does Rime's Funding Compare to Its Competitors?

Rime's $24 million Series A round, led by M13 Ventures with participation from Twilio Ventures, Corazon Capital, and Unusual Ventures, comes just 14 months after the company raised a $5.5 million seed round in May 2025. The rapid follow-up funding reflects investor confidence in the company's traction.

However, Rime is walking into a market with an obvious giant already in it. The Wall Street Journal reported in February 2026 that ElevenLabs raised $500 million at an $11 billion valuation and generated $330 million in recurring revenue in 2025, with plans to double that in 2026. ElevenLabs has pushed into customer service, onboarding, marketing, dubbing, and voice licensing, and it has the capital to chase enterprise phone calls if that becomes a priority.

Rime's narrower pitch is that phone calls deserve specialized models, not generic synthetic voices bolted onto whatever agent a company already uses. That gives it a sharper story than most startups in the space, but also less room to hide. If the voice misses a name, mangles a limited-time menu item, or sounds too cheerful for a drive-thru at rush hour, the customer hears the failure in real time.

What Will Rime Do With the New Funding?

With the $24 million Series A, Rime is planning to expand its team of 35 people, aiming to hire for model development, engineering, and partnerships. The company recently brought on Rafael Valle, who worked on audio understanding at Meta Superintelligence Labs and Nvidia's applied deep learning audio research team, as its chief scientist.

Morgan Blumberg, a partner at M13 Ventures who is joining Rime's board as part of the fundraise, explained the investment thesis: "Companies like ElevenLabs have moved into being an orchestration and the application layer, going head to head with the Sierras and Decagons of the world. I think there's just so much more to be done technically, and Rime's approach of pushing forward on the best model with low latency and high reliability in a regulated environment stands out".

The competitive landscape remains uncertain. ElevenLabs and Deepgram both have the resources to build call center-specific products of their own, and Twilio, now one of Rime's investors through Twilio Ventures, already runs infrastructure that carries a huge share of business phone calls. That distribution could be useful for Rime's growth, or it could signal a potential conflict of interest if Twilio decides to compete directly. For now, the $24 million buys Rime time to widen its enterprise base before larger companies turn their attention to the same phone lines Rime built for first.