The real-time voice AI that laughs, sighs, and emotes — sub-100ms latency for live agents.
Cartesia's Sonic 3 is built on state-space models instead of transformers, which is how it achieves latency low enough for live phone and voice-agent work. Beyond speed, its signature trick is genuine non-verbal emotion — laughter, sighs, whispering — generated inline from your text. It's become the default voice layer for a large share of production voice agents.
Who it's for: Voice-agent developers, call-center builders, and interactive apps where round-trip latency decides whether the experience works at all.
Inline laughter, breaths, and sighs — no audio editing needed.
Fast enough for natural back-and-forth on a live call.
One API for English, Spanish, Hindi, Japanese, and more.
Clone a voice from a few seconds of reference audio.
The no-brainer choice for voice agents and interactive audio where latency is physics. For audiobook narration or a giant voice catalog, ElevenLabs still has the edge.