Cartesia Sonic by Cartesia
Sonic TTS API (Sonic 3.6 claims 44 languages) with instant and pro voice cloning.
Voiceover (text-to-speech) Service
Price
Free tier
paid from $5 a month
Commercial use
With conditions
Credit the author
—
Agent access
Official MCP server
API key needed
Rules for your agent
Copied.
- Cartesia Sonic (Voiceover (text-to-speech)). Sonic TTS API (Sonic 3.6 claims 44 languages) with instant and pro voice cloning. Price: free tier; commercial use with conditions; ship inside your app with conditions. Connect: API docs https://docs.cartesia.ai (API key needed); npm @cartesia/cartesia-js; PyPI cartesia. Rule: Use Pro or above for commercial use; the commercial use license is a Pro-plan addition.
Paste it into your prompt or AGENTS.md. It is built from the license and API terms below.
License
| License | — |
|---|---|
| Commercial use | Commercial use with conditions |
| Credit | — |
| Inside your app or game | Ship inside your app with conditions |
| Monetized YouTube | Monetized YouTube with conditions |
| AI training | Not stated |
| Bots and bulk downloads | Not stated |
| Rules |
|
Connect it to an agent
| MCP server | Official |
|---|---|
| API | API docs · key needed |
| npm | npm install @cartesia/cartesia-js |
| PyPI | pip install cartesia |
| Status page | status.cartesia.ai |
Pricing
| Free | 20K credits/month (1 credit = 1 character; one minute of audio is about 750-800 credits). |
|---|---|
| Paid from | $5 a month |
| Usage price | Pro $5/100K credits; Startup $49/1.25M; Scale $299/month. |
| Good to know | Instant cloning from Pro; Pro Voice Clone needs Startup or above and 30+ minutes of audio. |
Sources
Read on Oct 10, 2026: cartesia.ai/pricing, docs.cartesia.ai/build-with-cartesia/tts-models/latest, docs.cartesia.ai/integrations/mcp.
Not confirmed: The free-plan commercial status is inferred from the plan table (ToS not read).
Not legal advice. Check the license page before you ship.
Alternatives to Cartesia Sonic
| Pick for your agent | Source | Price | License | Monetized YouTube | Agent access |
|---|---|---|---|---|---|
| ElevenLabs Text-to-speech and voice cloning API in many languages, with an official MCP server. |
Free tier · from $6/mo | Commercial: conditions | With conditions | MCP API | |
| Fish Audio TTS app and pay-as-you-go API priced per UTF-8 byte; S2.1-Pro claims 83 languages. |
Free tier · from $11/mo | Commercial: conditions | With conditions | MCP API | |
| Hume Octave Octave TTS with voice cloning and an official MCP server. |
Free tier · from $3/mo | Commercial: conditions | With conditions | MCP API | |
| Speechify API TTS API (Simba models) with a free plan that lists commercial use. |
Free tier · from $10/mo | Commercial OK | With conditions | API | |
| WellSaid TTS voices with commercial rights on paid plans; API access is available. |
Free tier · from $10/mo | Commercial: conditions | With conditions | API | |
| Chatterbox MIT-licensed open TTS with zero-shot cloning in 23 languages and a built-in Perth watermark. |
Free | Commercial OK No credit | Yes | PyPI | |
| Kokoro-82M 82M-parameter open-weight TTS model under Apache-2.0 with fixed voice packs. |
Free | Commercial OK No credit | Yes | npm | |
| Piper Fast local TTS engine (GPL-3.0) with downloadable voices under per-voice licenses. |
Free | Commercial: conditions Credit varies | With conditions | PyPI |
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Copied. Paste it into your prompt or AGENTS.md.