cartesia.ai
Sonic is a blazing fast, lifelike generative voice API (🚀 135ms model latency). Build high quality, real time voice experiences with a diverse voice library, instant voice cloning, voice mixing, and voice design with speed and emotion control.
| What is it | Sonic is a blazing fast, lifelike generative voice API (🚀 135ms model latency). Build high quality, real time voice experiences with a diverse voice library, instant voice cloning, voice mixing, and voice design with speed and emotion control. |
|---|---|
| Pricing | Freemium |
| Free tier | Yes |
| Platform | API |
| API | Yes |
| Best for | building conversational AI agents, enhancing customer support with voice |
| Domain registered | 2023 |
Data updated Aug. 1, 2026
What does cartesia.ai do?
Cartesia's Sonic-3 is a text-to-speech API designed specifically for creating dynamic, conversational voice agents. It goes far beyond simple robotic reading by generating speech that includes realistic laughter, emotional inflection (like excitement or sadness), and real-time streaming. This allows developers to build AI voices that sound genuinely human and engaged in a conversation, not just reciting text.
The tool stands out with its specific, technical features. It handles acronyms and initialisms intelligently (e.g., reading 'NASA' as a word), supports over 40 languages including multiple Indian dialects, and offers both instant voice cloning and professional-grade custom clones. Its biggest technical claim is ultra-low latency, boasting response times faster than a human blink, which is critical for making real-time conversations feel natural and not laggy.
This is a powerful tool for developers and product teams building voice-enabled applications. Obvious use cases include AI customer support agents that can laugh empathetically, interactive companions in gaming or wellness apps, logistics assistants for field workers, and healthcare bots that can convey trust and clarity. It's for anyone who needs a voice interface that doesn't sound like a machine.
Key features
What makes it stand outWho is cartesia.ai for?
Who benefits most from this toolPricing
Free tier available — start without a credit cardFree
- 20,000 credits
- 1 agent slots
- 1 prepaid agents
- 8 concurrent calls
- 8 concurrent stt requests
- 2 concurrent tts requests
- Sonic-3 API access
- Voice Changer
- Sonic-Turbo API access
- Infilling
- Voice Library
- Languages
- Design a Voice
- Line SDK
- Text to Agent
- Reasoning templates
- Telephony
- Call analytics
- Access to Sonic and Ink
- Background agents
- Github integration
- CLI
- Observability
- Ink-Whisper API access
- Multilingual support
Pro
Everything in Free, plus:
- 100,000 credits
- 3 agent slots
- 5 prepaid agents
- 12 concurrent calls
- 12 concurrent stt requests
- 3 concurrent tts requests
- Instant voice cloning
- Commercial Use
Startup
Everything in Pro, plus:
- 1,250,000 credits
- 5 agent slots
- 49 prepaid agents
- 20 concurrent calls
- 20 concurrent stt requests
- 5 concurrent tts requests
- Pro voice cloning
- Organizations
Scale
Everything in Startup, plus:
- 8,000,000 credits
- 10 agent slots
- 299 prepaid agents
- 60 concurrent calls
- 60 concurrent stt requests
- 15 concurrent tts requests
- Priority support
- High concurrency limits
Enterprise
Everything in Scale, plus:
- Custom agent slots
- Custom concurrent calls
- Custom concurrent stt requests
- Custom concurrent tts requests
- Custom usage pricing
- Custom concurrency
- Enterprise support via slack
- Enterprise-grade security & compliance
- Priority Dedicated Support via Slack
- Single Sign-On (SSO)
- PCI compliance
- Custom SLAs
- Custom Security Review
- HIPAA compliance
Trust & presence
Gallery
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