provider · Cartesia
Cartesia (Sonic)
Cartesia's Sonic model is built for one thing: speed. It streams audio back in well under 100ms, which is the difference between a voice agent that feels like a real conversation and one that feels like a phone menu with an awkward pause after every sentence. Sonic-2, released February 2026, covers 15+ languages and is positioned specifically as the latency leader among TTS APIs — competitors like ElevenLabs are excellent but noticeably slower to start speaking. For a student this is less "something you click a button on" and more the engine behind a live voice assistant, an interactive lab tutor, or any app where the AI needs to start talking back almost instantly. It is priced to be cheap at volume, which matters if you are building something that talks a lot rather than narrating a single video.
What it can help with
- real-time tts
- low-latency speech
- streaming audio
- voice agents
- multilingual tts
- high-volume usage
- instant voice response