
Cartesia
Real-time text-to-speech API for developers and voice agents.
About
Cartesia (cartesia.ai) is the developer TTS platform built for real-time use: the Sonic model family delivers low-latency streaming speech for voice agents, with instant voice cloning (10 seconds of audio) and 44 languages.
Pricing (2026): free tier ~20k credits/mo; Pro from ~$4–5/mo with instant cloning. The developer favorite for conversational AI — ElevenLabs' sharpest rival on the API side.
What it can do
- Real-time streaming TTS
- Sonic model family
- Instant voice cloning
- 44 languages
- Voice-agent ready
Setup
- Sign up at cartesia.ai and get an API key.
POST /tts/byteswith text + voice id.- Stream audio via WebSocket for real-time agents.
- Clone a voice with 10s of reference audio (Pro).
Prerequisites
API key; paid tier for cloning.
Use cases
Works with
Trust score — 7/10
Scored 7/10 (metrics tier). Strong developer traction in 2026 with real-time TTS and competitive pricing, but proprietary with provider-tier adoption estimates (thinner evidence). Metrics tier.
How the trust score is built
Full methodology →- Adoption · stars/downloads, log-scaled vs peers
- 7.0/10
- Maintenance · recency, releases, issue load
- 7.0/10
- Openness · license + docs
- 4.8/10
- Manual review · sanity read + red-flag check
- 8.0/10
- · provider-tier estimate — thinner evidence (no public adoption metric)
- · developer TTS; no public repo — adoption estimated
- · released 285 days ago
- · manual review: real-time TTS/voice-agent API (Sonic); Pro from ~$4-5/mo; strong developer traction in 2026; license: proprietary
Sources
Every fact above was checked against these sources. Where a claim comes from the provider and couldn't be independently verified, the text says so.