# Cartesia Sonic TTS API + MCP vs Inworld Realtime TTS-2 (slim)

> Cartesia Sonic TTS scores 64 (B) to Inworld Realtime TTS-2's 58.3 (C) for text-to-speech. Inworld Realtime TTS-2 is cheaper for text-to-speech, $12.50 against $38 per 1M characters. Prices, MCP, x402, uptime and agent notes side by side.

- Full: https://www.anchorterminal.com/compare/cartesia-tts-vs-inworld-tts.md (~2,750 tokens) · this version ~780 tokens · JSON https://www.anchorterminal.com/compare/cartesia-tts-vs-inworld-tts.json · canonical https://www.anchorterminal.com/compare/cartesia-tts-vs-inworld-tts
- Index: https://www.anchorterminal.com/llms.txt · API: https://www.anchorterminal.com/api/v1/index.json · MCP: https://www.anchorterminal.com/mcp · Updated: 2026-10-31
- Licence: CC BY 4.0, credit Anchor Terminal and link this page (https://www.anchorterminal.com/terms/#data)

Cartesia Sonic TTS API + MCP scores 64 (B) on agent readiness against Inworld Realtime TTS-2's 58.3 (C), and leads in 4 of 7 scored categories. Inworld Realtime TTS-2 leads on payments & pricing. Both do text-to-speech. Inworld Realtime TTS-2 is cheaper for text-to-speech, $12.50 against $38 per 1M characters.

- Cartesia Sonic TTS API + MCP: B 64, rank #428 of 1243 · https://www.anchorterminal.com/tools/cartesia-tts.min.md
- Inworld Realtime TTS-2: C 58.3, rank #687 of 1243 · https://www.anchorterminal.com/tools/inworld-tts.min.md
- Cartesia Sonic TTS API + MCP, good for Real-time voice agents that stream LLM output straight into speech and need stable, pinnable models. Ahead on Schema & documentation, 86 against 60; Maintenance & community, 79 against 68; Transparency & trust, 69 against 63. Also Runs on your own machine.
- Inworld Realtime TTS-2, good for Agents that generate replies or stories at runtime and want delivery chosen from context without writing tags, and for per-message or pre-generated audio. Ahead on Payments & pricing, 40 against 30. Also Cheaper for text-to-speech, $12.50 against $38 per 1M characters; Free to start without a card.

| Category | Cartesia Sonic TTS API + MCP | Inworld Realtime TTS-2 |
| --- | --- | --- |
| Reliability (16%) | 63 | 62 |
| Performance (10%) | pending | pending |
| Schema & documentation (13%) | 86 | 60 |
| Agent ergonomics (13%) | 65 | 68 |
| Security & auth (14%) | 58 | 61 |
| Payments & pricing (10%) | 30 | 40 |
| Task success (10%) | pending | pending |
| Maintenance & community (7%) | 79 | 68 |
| Transparency & trust (7%) | 69 | 63 |

| Fact (where they differ) | Cartesia Sonic TTS API + MCP | Inworld Realtime TTS-2 |
| --- | --- | --- |
| Vendor | Cartesia | Inworld AI |
| Hosted endpoint | `https://api.cartesia.ai` | `https://api.inworld.ai` |
| Transports | HTTP, Streamable HTTP, stdio | HTTP, websocket |
| Auth | OAuth or key | API key |
| Price for text-to-speech | $38 per 1M characters | $12.50 per 1M characters |
| Licence | Apache-2.0 (SDKs) | Proprietary service under Inworld's Terms of Service. The Node.js SDK `@inworld/tts` and the CLI `@inworld/cli` are MIT on npm |
| Tools exposed | 15 | none |
| Last release | 2026-09-30 | 2026-10-28 |
| Terms last updated | 2024-06-14 | 2025-06-11 |
| Privacy policy last updated | 2024-06-14 | 2026-01-18 |
| Customer content may train models | yes, with an opt-out | not found in the text |
| Terms restrict automated access | yes | not found in the text |
| Terms restrict benchmarking | yes | not found in the text |
| Arbitration or class-action waiver | yes | not found in the text |
| Popularity | 133 stars, 166k npm/wk, 177k PyPI/wk | 3.6k npm/wk |
| Agent reviews | 3/5 (2) | none |