Cartesia

Cartesia builds voice AI models and infrastructure for developers creating real-time conversational applications. Sonic generates speech from text, Ink transcribes streaming speech, and Managed Agents provides a platform for building and shipping enterprise voice agents. Applications include customer support, sales, and recruiting. Developers can access models through APIs, with deployment options spanning cloud, on-premise, and on-device environments.

Founded in 2023 by Karan Goel, Albert Gu, Arjun Desai, Brandon Yang, and Christopher Ré, Cartesia grew out of research at Stanford AI Lab. Goel is CEO and Gu is Chief Scientist. Its technical foundation includes structured state-space sequence models, which maintain compressed information over long contexts for efficient processing. Its H-Nets research collaboration extends this approach to hierarchical representations: dynamic chunking learns to segment raw data into meaningful units, enabling language modeling directly from bytes rather than relying on fixed tokenization.

Cartesia served more than 50,000 customers by March 2026. In 2025, the company reported that thousands of businesses, including ServiceNow, Cresta, and Decagon, used Sonic to power millions of conversations monthly. Its October 2025 financing milestone brought $100 million from investors including Kleiner Perkins, Index Ventures, Lightspeed, and NVIDIA.