Free
$0
Entry tier for testing text-to-speech and transcription
- 20K credits/month
- Text to Speech
- Speech to Text
- 2 concurrent TTS requests
- 1 phone number
Cartesia
Real-time speech AI for developers: fast text-to-speech, transcription and voice agents
Freemiumcartesia.aiUpdated
About Cartesia
Cartesia is a speech AI platform for developers and enterprises that provides text-to-speech, speech-to-text and managed voice agents through an API. Its Sonic models generate speech with a published time to first audio of about 90 milliseconds, and its Ink models handle streaming transcription with built-in turn detection. Voices can be cloned from a short audio clip, with the docs citing support for 40+ languages and accents.
Best for
- Low-latency voice agents, real-time text-to-speech and streaming transcription inside applications
- Customer Service Voice Agents: Building phone agents that answer and place calls using Ink, an LLM and Sonic.
- Outbound Verification Calls: Real-time calls for step-up authentication and identity checks.
- Live Voice Features in Apps: Adding streaming text-to-speech to assistants, games and interactive products.
- Streaming Transcription: Using Ink-2 with turn detection for live captioning and conversation capture.
- Branded Custom Voices: Cloning a company voice and localizing it into additional accents.
Not ideal for
- Non-technical users wanting a consumer voiceover app, or teams needing a large library of preset narration voices
Popular with
- Developers
- Voice AI Engineers
- Contact Centre Teams
- Enterprises
- Product Teams
Screenshots
Key features
- Sonic Text-to-Speech
- Ink Speech-to-Text
- Managed Agents
- Voice Cloning
- Pronunciation Dictionaries
- Regional API Routing
- Telephony Support
- Python and JavaScript SDKs
- Usage and Access Controls
Pros and cons
Pros
- Published time to first audio of about 90 ms for Sonic 3.6, suited to live conversation.
- Free tier with 20K credits per month and a $5 Pro plan with commercial use and instant cloning.
- One platform covers text-to-speech, speech-to-text and managed voice agents.
- Regional endpoints in the US, EU and APAC, with on-premise and on-device options.
- Frequent releases: the changelog shows monthly model, voice and API updates in 2026.
- Ranked first on Artificial Analysis speech leaderboards according to the company.
Cons
- The free tier has no instant voice cloning, only 2 concurrent TTS requests and no commercial license.
- Credit-based billing with overage up to $65 per 1M credits can be hard to forecast as usage grows.
- Independent reviews note a smaller preset voice library than some narrative-focused competitors.
- Developer-oriented; there is no consumer app and no released iOS or Android app.
Pricing
Plans as listed by the vendor on . Check their site for current prices.
Pro
$5/month
Individuals building with commercial use rights
- 100K credits/month
- commercial use license
- instant voice cloning
- 3 concurrent TTS requests
Startup
$49/month
Small teams shipping voice products
- 1.25M credits/month
- professional voice cloning (2 slots)
- Organizations
- 5 concurrent TTS requests
Scale
$299/month
Higher-volume production workloads
- 8M credits/month
- priority support
- high concurrency
- 15 concurrent TTS requests
- 4 professional voice clone slots
Enterprise
Custom/custom
Large organizations with custom requirements
- Custom limits
- DPAs and BAAs
- SSO
- shared Slack channel
- security questionnaire support
Our ratings
Scored out of 10 by the Finder Atlas editorial team.
8.3overall
- Ease of Use
- 7.8
- Feature Depth
- 8.5
- Value for Money
- 8.2
- Performance & Speed
- 9.0
- Documentation & Support
- 8.2
Platforms and integrations
Available on
- Web
- API
Works with
- Twilio
- Anthropic
- OpenAI
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Release history
Sonic 3.6 became generally available with Odia and Urdu support, and Managed Agents launched with hosted LLMs and bui...
Sonic 3.6 became generally available with Odia and Urdu support, and Managed Agents launched with hosted LLMs and built-in tools.
Ink-2 speech-to-text added Spanish, French, Hindi and Japanese
Ink-2 speech-to-text added Spanish, French, Hindi and Japanese.
Ink-2 launched, initially English-only, alongside Sonic 3.5 general availability
Ink-2 launched, initially English-only, alongside Sonic 3.5 general availability.
US, EU and APAC routing launched
US, EU and APAC routing launched.
Reviews
No reviews yet
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Frequently asked questions
What is Cartesia Sonic?
Sonic is Cartesia's text-to-speech model family. The current generation, Sonic 3.6, became generally available in August 2026 and is listed with about 90 ms time to first audio.
Does Cartesia have a free plan?
Yes. The Free plan costs $0 and includes 20K credits per month, text-to-speech and speech-to-text, but no instant voice cloning. A commercial use license starts on the $5 Pro plan.
Can I clone a voice with Cartesia?
Instant voice cloning is available on Pro and above, and professional voice clones on Startup, Scale and Enterprise. The docs state cloning works from a 10-second clip across 40+ languages and accents.
How much does a voice agent cost?
Agent call duration is $0.06 per minute, plus $0.014 per minute for telephony on a Cartesia-provided number. LLM usage was free for UI-created agents until October 1, 2026.
Can Cartesia run on-premise or on-device?
The website lists cloud deployment through regional API endpoints, as well as on-premise and on-device options. Details are not published on the pages reviewed.
Which older models are being retired?
The changelog says Sonic-2, Sonic-turbo and Sonic-3-2025-10-27 will be retired after October 20, 2026, and Line SDK agents stop being hosted on December 1, 2026.
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