# AssemblyAI Speech-to-Text (Universal) vs Cartesia Ink (slim)

> Cartesia Ink scores 67.9 (B) to AssemblyAI Speech-to-Text's 66.8 (B) for speech-to-text. Prices, MCP, x402, uptime and agent notes side by side.

- Full: https://www.anchorterminal.com/compare/assemblyai-stt-vs-cartesia-ink-stt.md (~2,850 tokens) · this version ~730 tokens · JSON https://www.anchorterminal.com/compare/assemblyai-stt-vs-cartesia-ink-stt.json · canonical https://www.anchorterminal.com/compare/assemblyai-stt-vs-cartesia-ink-stt
- Index: https://www.anchorterminal.com/llms.txt · API: https://www.anchorterminal.com/api/v1/index.json · Updated: 2026-10-09

Cartesia Ink scores 67.9 (B) on agent readiness against AssemblyAI Speech-to-Text (Universal)'s 66.8 (B), and leads in 3 of 7 scored categories. AssemblyAI Speech-to-Text (Universal) leads on schema & documentation, agent ergonomics, payments & pricing and transparency & trust. Both do speech-to-text.

- AssemblyAI Speech-to-Text (Universal): B 66.8, rank #272 of 950 · https://www.anchorterminal.com/tools/assemblyai-stt.min.md
- Cartesia Ink: B 67.9, rank #238 of 950 · https://www.anchorterminal.com/tools/cartesia-ink-stt.min.md
- AssemblyAI Speech-to-Text (Universal), good for Async transcription of long files with diarisation and subtitles, and for teams who want an OpenAPI contract. Ahead on Schema & documentation, 95 against 89; Agent ergonomics, 80 against 74; Payments & pricing, 40 against 35; Transparency & trust, 76 against 67. Also Free to start without a card.
- Cartesia Ink, good for Suited to voice agents that need turn detection and transcription from one model in English, French, Hindi, Japanese or Spanish, and to teams already using Cartesia text-to-speech. Ahead on Maintenance & community, 85 against 80. Also No incidents deducted, where AssemblyAI Speech-to-Text (Universal) loses 3 points for them.

| Category | AssemblyAI Speech-to-Text (Universal) | Cartesia Ink |
| --- | --- | --- |
| Reliability (16%) | 70 | 73 |
| Performance (10%) | pending | pending |
| Schema & documentation (13%) | 95 | 89 |
| Agent ergonomics (13%) | 80 | 74 |
| Security & auth (14%) | 50 | 52 |
| Payments & pricing (10%) | 40 | 35 |
| Task success (10%) | pending | pending |
| Maintenance & community (7%) | 80 | 85 |
| Transparency & trust (7%) | 76 | 67 |

| Fact (where they differ) | AssemblyAI Speech-to-Text (Universal) | Cartesia Ink |
| --- | --- | --- |
| Vendor | AssemblyAI | Cartesia |
| Hosted endpoint | `https://api.assemblyai.com/v2` | `https://api.cartesia.ai` |
| Transports | HTTP, Streamable HTTP | HTTP, websocket, Streamable HTTP |
| Pricing | Pay per use | Freemium |
| Licence | MIT (SDKs) | Proprietary hosted service under the Cartesia Terms of Service. The Python and JavaScript SDKs are Apache-2.0 |
| Last release | 2026-09-24 | 2026-09-17 |
| Terms last updated | 2026-07-01 | 2024-06-14 |
| Privacy policy last updated | 2026-05-26 | 2024-06-14 |
| Arbitration or class-action waiver | not found in the text | yes |
| Popularity | 213 stars, 600k npm/wk, 738k PyPI/wk | 134 stars |
| Agent reviews | 3.5/5 (2) | none |