Glossary · AI & Agents
Cartesia
Overview
What Cartesia is
Cartesia is an AI research and infrastructure company focused on real-time generative voice. Its flagship product is Sonic, a text-to-speech model designed for very low latency so that generated speech can begin almost immediately, which is critical for live conversation.
Cartesia offers its models through an API, with capabilities including streaming speech synthesis, a library of voices, and voice cloning. It positions itself for developers building interactive voice applications rather than only batch audio generation.
How it works
Developers send text to Cartesia's API and receive synthesized audio, typically streamed in small chunks so playback can start before the full response is generated. This streaming design keeps perceived latency low, which matters when speech is one turn in a back-and-forth conversation.
Cartesia is often used as the text-to-speech stage inside a larger voice pipeline, paired with a speech-to-text service and a language model. It integrates with agent frameworks and orchestration tools such as Pipecat and LiveKit.
Why it matters
For voice agents and assistants, latency is the difference between a natural exchange and an awkward one. By optimizing for real-time synthesis, Cartesia targets the conversational use cases where slower TTS engines feel laggy.
It competes in a market that includes ElevenLabs, Deepgram's Aura, PlayHT, and OpenAI's voice models. Choosing among them usually comes down to latency, voice quality, language coverage, pricing, and how well each fits an existing pipeline. As with any voice cloning tool, use requires appropriate consent and rights to the voices involved.
Where we use it
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How our team puts Cartesia to work in real projects.
FAQ
Cartesia — common questions
What is Cartesia's Sonic model?
Sonic is Cartesia's generative text-to-speech model built for low-latency, real-time speech synthesis. Its speed makes it well suited to live voice agents and assistants where responses must begin almost instantly.
What is Cartesia used for?
Cartesia is used to add real-time, natural-sounding speech to applications such as voice agents, phone assistants, and interactive tools. It typically serves as the text-to-speech layer in a voice pipeline alongside speech recognition and a language model.
How does Cartesia compare to ElevenLabs?
Both offer high-quality generative voices and voice cloning via API. Cartesia emphasizes very low latency for real-time conversation, while ElevenLabs is known for expressive quality and a large voice library. The right choice depends on latency needs, quality, and pricing.
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