Cartesia

Low-latency voice API built for real-time agents and streaming speech

AI Audio & MusicFree planOverseasβ˜…β˜…β˜…β˜†β˜† 3.0

What is Cartesia?

Cartesia is a voice AI company whose Sonic text-to-speech models are built on state-space architectures instead of transformers, a choice aimed squarely at time-to-first-audio. The result is streaming speech quick enough for live phone agents and conversational apps, with emotional control and instant voice cloning from a short sample. Deployment can be cloud, on-premise or on-device for teams that cannot send audio out. It is infrastructure for developers rather than a studio: there is a playground and SDKs, but no timeline editor. Latency numbers should be measured on your own traffic.

Last updated: 2026-09-20. This site only provides an index; for exact features, pricing, and licensing, see the official website.

Key features

  • Streaming text-to-speech API tuned for very low time-to-first-audio
  • Instant voice cloning from roughly ten seconds of reference audio
  • Emotion, pacing and expression controls including laughter
  • Speech-to-text models for full speech-in, speech-out pipelines
  • Runs in the cloud, on-premise or on device through SDKs
  • Telephony and agent framework integrations for phone agents

Pros & cons

Strengths

  • Latency is the headline feature and it holds up in live agents
  • A usable voice clone comes from a very short audio sample
  • On-premise and on-device options suit data-sensitive deployments

Watch out for

  • Developer infrastructure: expect to build rather than click
  • Latency needs benchmarking, since results vary by region and load
  • Free tier is limited and intended for non-commercial evaluation

Best for & use cases

voice agents, phone support bots, live translation and interactive apps

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FAQ

What makes Cartesia fast?

The Sonic models use a state-space architecture rather than the transformer design behind most speech models. That approach streams audio with very low time-to-first-audio, which is what makes a spoken exchange feel immediate instead of delayed.

Can I clone a voice?

Yes, instant cloning works from a sample of roughly ten seconds, and a higher-fidelity professional clone is available on higher tiers. Consent and local law still govern what you may do with another person's voice.

Is there a studio interface?

Not really. There is a playground for testing voices and an API for production, but it is not a video or podcast editing tool. Teams normally pair it with their own front end or agent framework.