# Cartesia Ink vs Groq Speech-to-Text

> Groq Speech-to-Text scores 71.8 (BB) to Cartesia Ink's 67.9 (B) for speech-to-text. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/cartesia-ink-stt-vs-groq-speech-to-text
- Markdown: https://www.anchorterminal.com/compare/cartesia-ink-stt-vs-groq-speech-to-text.md (~2,850 tokens)
- Slim: https://www.anchorterminal.com/compare/cartesia-ink-stt-vs-groq-speech-to-text.min.md (~730 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/cartesia-ink-stt-vs-groq-speech-to-text.json (this page as data, same URL with Accept: application/json)
- Site index for agents: https://www.anchorterminal.com/llms.txt (full text: https://www.anchorterminal.com/llms-full.txt)
- API: https://www.anchorterminal.com/api/v1/index.json
- Updated: 2026-10-09

Groq Speech-to-Text scores 71.8 (BB) on agent readiness against Cartesia Ink's 67.9 (B), and leads in 5 of 7 scored categories. Cartesia Ink leads on schema & documentation and maintenance & community. Both do speech-to-text.

- Cartesia Ink: grade B, 67.9/100, rank #238 of 950. Markdown https://www.anchorterminal.com/tools/cartesia-ink-stt.md · JSON https://www.anchorterminal.com/api/v1/tools/cartesia-ink-stt.json
- Groq Speech-to-Text: grade BB, 71.8/100, rank #117 of 950. Markdown https://www.anchorterminal.com/tools/groq-speech-to-text.md · JSON https://www.anchorterminal.com/api/v1/tools/groq-speech-to-text.json
- Best speech-to-text APIs for AI agents: https://www.anchorterminal.com/best/speech-to-text/index.md
- All 91 stt comparisons: https://www.anchorterminal.com/compare/speech-to-text/index.md

## Which one, for what

### Cartesia Ink (B)

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:
- Schema & documentation, 89 against 58
- Maintenance & community, 85 against 68

Watch for: The terms let Cartesia train models on inputs and outputs unless otherwise agreed. Opting out is a form in the Playground's data controls

### Groq Speech-to-Text (BB)

Good for: Suited to cheap, fast transcription of recorded files in many languages, and to agents that already hold a Groq key or use an OpenAI-compatible client.

Ahead on:
- Reliability, 90 against 73
- Security & auth, 79 against 52
- Payments & pricing, 40 against 35
- Transparency & trust, 85 against 67

Also in its favour:
- Agent-ready, a grade of BB or better
- Free to start without a card

Watch for: No streaming or realtime endpoint and no diarisation in the reviewed documentation


## Score by category

| Category | Weight | Cartesia Ink | Groq Speech-to-Text | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 73 | 90 | Groq Speech-to-Text +17 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 89 | 58 | Cartesia Ink +31 |
| Agent ergonomics | 13% (16.2 this run) | 74 | 75 | Groq Speech-to-Text +1 |
| Security & auth | 14% (17.5 this run) | 52 | 79 | Groq Speech-to-Text +27 |
| Payments & pricing | 10% (12.5 this run) | 35 | 40 | Groq Speech-to-Text +5 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 85 | 68 | Cartesia Ink +17 |
| Transparency & trust | 7% (8.8 this run) | 67 | 85 | Groq Speech-to-Text +18 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **67.9 · B** | **71.8 · BB** | |

## Facts side by side

| Fact | Cartesia Ink | Groq Speech-to-Text |
| --- | --- | --- |
| Kind | Model API | Model API |
| Vendor | Cartesia | Groq |
| Hosted endpoint | `https://api.cartesia.ai` | `https://api.groq.com/openai/v1` |
| Transports | HTTP, websocket, Streamable HTTP | HTTP |
| Auth | API key | API key |
| Pricing | Freemium | Freemium |
| x402 | no | no |
| Licence | Proprietary hosted service under the Cartesia Terms of Service. The Python and JavaScript SDKs are Apache-2.0 | Proprietary hosted service under the Groq Services Agreement. The SDKs are Apache-2.0 and the Whisper weights are published by OpenAI on Hugging Face |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| Last release | 2026-09-17 | 2026-08-26 |
| Terms last updated | 2024-06-14 | 2026-06-22 |
| Privacy policy last updated | 2024-06-14 | 2025-11-12 |
| 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 | yes |
| Terms or service can change without notice | not found in the text | not found in the text |
| Arbitration or class-action waiver | yes | not found in the text |
| Popularity | 134 stars | 621 stars |

## Verdicts

**Cartesia Ink.** Ink 2 streams transcripts with turn detection built into the model, documented by an AsyncAPI file with typed ranges and structured errors. The terms, last revised 14 June 2024, let Cartesia train on inputs and outputs unless the customer opts out, and zero data retention is an Enterprise setting. Ink 2 has no batch endpoint and no diarisation.

**Groq Speech-to-Text.** Whisper Large v3 Turbo costs $0.04 an audio hour and Whisper Large v3 $0.111, with a no-card free plan and zero data retention as a self-serve setting. There is no streaming endpoint, no diarisation and no subtitle output, and uploads stop at 25 MB on the free plan and 100 MB on the Developer plan.

## Before you call either

### Cartesia Ink

1. Use `wss://api.cartesia.ai/stt/turns/websocket` with `model=ink-2`, `encoding`, `sample_rate` and `cartesia_version=2026-08-14`. All four are required.
2. Send raw mono audio in chunks of about 100 ms at the speed it was spoken. Pushing a whole file into the socket can return an internal server error.
3. Read the final text from `turn.end` only. `transcript` is cumulative within a turn, so joining `turn.update` events duplicates text.
4. Send `{"type": "close"}` after the last audio and keep reading until the server closes the socket, or the buffered tail is lost.
5. Check `encoding` and `sample_rate` against the source before sending. The docs say the server might not return an error when they are wrong.

### Groq Speech-to-Text

1. Send `whisper-large-v3-turbo` for transcription and `whisper-large-v3` for translation to English. The translations endpoint does not accept Turbo.
2. Pass `url` instead of `file` for audio over 25 MB, and split anything over the plan's size limit into overlapping chunks before sending.
3. Set `response_format` to `verbose_json` before asking for `timestamp_granularities[]`. Word timestamps add latency, segment timestamps do not.
4. Every request is billed as at least 10 seconds of audio, so join very short clips where the task allows.
5. Read `retry-after` on a 429 and back off. Audio limits count seconds an hour and a day as well as requests.

## Questions

### Which is better for AI agents, Cartesia Ink or Groq Speech-to-Text?

Groq Speech-to-Text scores 71.8 (BB) on agent readiness against Cartesia Ink's 67.9 (B), and leads in 5 of 7 scored categories. Cartesia Ink leads on schema & documentation and maintenance & community.

### Do Cartesia Ink and Groq Speech-to-Text need an API key?

Both need an API key.

### Can an agent call Cartesia Ink and Groq Speech-to-Text without installing anything?

Yes. Cartesia Ink has a hosted endpoint at https://api.cartesia.ai and Groq Speech-to-Text at https://api.groq.com/openai/v1.


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/cartesia-ink-stt-vs-groq-speech-to-text.json, and with the fewest tokens: https://www.anchorterminal.com/compare/cartesia-ink-stt-vs-groq-speech-to-text.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "cartesia-ink-stt", "b": "groq-speech-to-text"}`. From a terminal: `anchor compare cartesia-ink-stt groq-speech-to-text`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/cartesia-ink-stt.json and https://www.anchorterminal.com/api/v1/tools/groq-speech-to-text.json

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