US voice AI startup Rime raises $24m to overhaul enterprise calls
San Francisco-based Rime has raised $24 million to build speech-to-speech AI models that aim to finally replace legacy customer service systems, a development that highlights both the current limitations and the fierce competition in the enterprise voice market.
Rime, a San Francisco-based artificial intelligence company, has secured $24 million in a Series A funding round led by M13 Ventures. The capital injection will support the startup's push to build voice AI models capable of handling enterprise customer service calls across sectors like healthcare and finance.
Rather than stringing together separate models for transcription, text generation, and voice synthesis, Rime is developing integrated speech-to-speech systems. This architecture is designed to cut latency, handle background noise, and reduce the complex orchestration that currently plagues AI phone agents.
To differentiate itself in a crowded market, Rime records its own conversational data at a dedicated San Francisco studio instead of scraping the web. It employs a phoneme-based architecture that handles industry-specific terminology and brand names without requiring clients to heavily customize or retrain the models.
Despite the hype around voice AI, the technology remains a tough sell for large organizations. “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 co-founder Lily Clifford.
The enterprise voice sector is rapidly fragmenting. European AI firm ElevenLabs has expanded from pure model development into orchestration and applications, competing directly with support-focused startups like Sierra and Decagon. M13’s Morgan Blumberg, who is joining Rime’s board, argued that the market needs deeper technical focus: “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.”
Rime has already signed contracts in heavily regulated industries, listing the Mayo Clinic, Upstart, Dialpad and Asurion among its clients. The company plans to use the funding to expand its 35-person team, recently hiring former Meta and NVIDIA audio researcher Rafael Valle as chief scientist. The round also included Twilio Ventures, Corazon Capital, and Unusual Ventures, following a $5.5 million seed round last May.
