Cartesia Sonic
the voice-agent default: streaming-first, low latency
the go-to for voice agents: streaming-first by design with a vendor-claimed sub-100ms latency and clean credit pricing. quality is very good though not always top of the arena — check tts arena v2 for current standing.
cartesia's sonic line is built for real-time: streaming-first architecture, instant voice cloning, and low latency by design, billed at one credit per character with a genuine free tier and plans scaling from $5/mo. for building a voice agent where time-to-first-audio is the metric that matters, it's the most natural pick in the category.
the honest caveats: the credit accounting is more opaque than a flat per-character rate, its sub-100ms claim is unbenchmarked, and while quality is very good it isn't always the arena leader. for agents specifically, that's usually the right trade.
the description above is ours, condensed from the ranking. pricing moves — check it on the vendor's own page before you rely on it.
- category
- ai text-to-speech models
- pricing
- free tier; from $5/mo (Pro)
- website
- cartesia.ai
the go-to for voice agents: streaming-first by design with a vendor-claimed sub-100ms latency and clean credit pricing. quality is very good though not always top of the arena — check tts arena v2 for current standing.
we researched this category against vendors' own pricing pages and licence files. that is where this line comes from — not from the vendor, and not from anything they paid for.
more ai text-to-speech models
ElevenLabs
we checked this$0.05 per 1K chars (Flash/Turbo v2.5)the quality and ecosystem leader, agents to narration
OpenAI TTS
we checked this$15 per 1M chars (tts-1)cheap, steerable, and one client if you're already on openai