# Cartesia Ink vs MiniMax Speech-to-Text

> Cartesia Ink scores 67 (B) to MiniMax Speech-to-Text's 48.4 (D) for speech-to-text. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/cartesia-ink-stt-vs-minimax-stt
- Markdown: https://www.anchorterminal.com/compare/cartesia-ink-stt-vs-minimax-stt.md (~5,700 tokens)
- Site index for agents: https://www.anchorterminal.com/llms.txt (the key docs and every listing in one file, at most 16 MB, about 4 million tokens: https://www.anchorterminal.com/llms-full.txt)
- API: https://www.anchorterminal.com/api/v1/index.json
- MCP: https://www.anchorterminal.com/mcp (the whole catalogue as tools, no key)
- DNS: dig +short TXT <slug>.grade.anchorterminal.com (the grade as a DNS TXT record, for a sandbox with no HTTP where names still resolve; also top., best.<category>. and <a>.vs.<b>. under the zone, and the same under grade.letme.dev)
- Licence: CC BY 4.0, credit Anchor Terminal and link this page (https://www.anchorterminal.com/terms/#data)
- Updated: 2026-11-07

Cartesia Ink scores 67 (B) on agent readiness against MiniMax Speech-to-Text's 48.4 (D), and leads in every scored category. Both do speech-to-text.

- Cartesia Ink: grade B, 67/100, rank #341 of 1510. Markdown https://www.anchorterminal.com/tools/cartesia-ink-stt.md · JSON https://www.anchorterminal.com/api/v1/tools/cartesia-ink-stt.json
- MiniMax Speech-to-Text: grade D, 48.4/100, rank #1126 of 1510. Markdown https://www.anchorterminal.com/tools/minimax-stt.md · JSON https://www.anchorterminal.com/api/v1/tools/minimax-stt.json
- Best speech-to-text APIs for AI agents: https://www.anchorterminal.com/best/speech-to-text/index.md
- All 320 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:
- Reliability, 73 against 47
- Schema & documentation, 89 against 82
- Security & auth, 47 against 33
- Payments & pricing, 35 against 20
- Maintenance & community, 84 against 6
- Transparency & trust, 68 against 63

Also in its favour:
- A hosted endpoint, with nothing to install

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

### MiniMax Speech-to-Text (D)

Good for: Cheap file transcription with diarisation and subtitles, strongest on Chinese and code-switched audio by the vendor's account.

Watch for: Files only, up to 500 seconds and 50 MB; live audio input isn't supported


## Why the edge

### Maintenance & community: Cartesia Ink +78

- Cartesia Ink (84): Read as a model, on the lines deepgram-stt, gladia-stt and cartesia-tts use for hosted speech models (recency 30, dated releases 10, deprecation notice 10, support 15, issues 10, SDKs 15, health 10). The `cartesia-mcp` server, which has a `speech_to_text` tool, released 0.28.1 on 30 October 2026 with a bug fix, after 0.27.0 (20 October) and 0.28.0 (27 October). The model page still dates `ink-2` and `ink-preview` 17 September 2026 (30). In the 90 days from 3 August the SDKs released 4.0.0, 4.0.1, 4.1.0 and 4.2.0 (14 August to 2 September) and the MCP server several releases, with changelog entries for August and September (10). The deprecations page gives dated sunsets, and Sonic-2, Sonic Turbo and `sonic-3-2025-10-27` were sunset after 20 October 2026, announced in the July changelog. No minimum notice period is stated and no Ink model has been retired, read as cartesia-tts is on the same page (5 of 10). The changelog has speech-to-text entries in May, June, July and September 2026, dated by month only, and no October entry (11 of 15). The Python SDK repository had 4 open issues on 9 October, per that check, not re-read on 1 November since GitHub's pages answered 403 (5 of 10). Official `cartesia` and `@cartesia/cartesia-js` SDKs at 4.2.0 (2 September 2026), generated for API version 2026-08-14 (15). CI workflows, release automation and lock files in both SDK repositories, with dependency updates merged on 23 October (8 of 10). 30 + 10 + 5 + 11 + 5 + 15 + 8 = 84.
- MiniMax Speech-to-Text (6): Read as a model. No dated release or change of `asr-1.0` was found on the model or API release notes or the status page (0). No dated ASR entries in the last 90 days (0). Support by email and Discord, not tested (6 of 15). No official SDK, and the MCP servers have no transcription tool (0 of 15). No package to judge (0 of 10). Total 6.

### Reliability: Cartesia Ink +26

- Cartesia Ink (73): Hosted reading. The status page at status.cartesia.ai (incident.io) lists Speech to Text as its own component in four regions (20). Its RSS feed, re-read on 1 November, now names each incident's components. In the 90 days from 3 August two incidents touch speech-to-text, both partial and read as minor, as this run reads one region or some requests. On 2 September some clients in the US regions saw connection errors that cleared on retry (Text to Speech and Speech to Text, US), and on 7 October customers in the US regions saw higher latency for some API requests, from 12:29 to about 18:23 (partial outage, Text to Speech, Speech to Text and Voice Cloning, US). The 3 September throttling named only Text to Speech in APAC, the 8 October errors only the Playground and Voice Agents, and the 15 October Playground outage says API services were unaffected. The 1 August API-wide incident has left the window. Minor only (20). Concurrency limits are published per plan, 8, 12, 20 and 60 concurrent STT requests, with a 3-minute idle timeout on sockets (15). Exceeding the limit returns 429 with the `concurrency_limited` code, and the SDKs retry 429 and 5xx twice with backoff on HTTP calls. No `Retry-After` header, backoff guidance or reconnection advice for a dropped socket was found (8 of 15). No SLA was found for any plan (0). `ink-2` is marked Stable on the model page re-read on 1 November, with `ink-preview` as the preview line (10). 20 + 20 + 15 + 8 + 0 + 10 = 73.
- MiniMax Speech-to-Text (47): Atlassian Statuspage at status.minimax.io with component history, but its components are LLM, Text-to-Speech and Video Generation, with none for speech to text (10 of 20). With no component, the history holds no record for transcription (5). Limits published with numbers, 2 concurrent connections and 30,000 audio seconds a minute (15). 429 is documented as `rate_limit_error`, and the general error code page says to retry later, with no backoff figures or Retry-After (7 of 15). No SLA in the terms or docs (0). `asr-1.0` is called the current public model with no beta label (10). 10 + 5 + 15 + 7 + 0 + 10 = 47.

### Payments & pricing: Cartesia Ink +15

- Cartesia Ink (35): No x402, MPP or L402 (0). The docs pricing page gives 3 credits a second for `ink-2` and the public pricing page gives plan prices and overage rates of $65, $45 and $38 per million credits, all read without a login (20). The Free plan is $0 with 20,000 credits a month, about 1 hour 51 minutes of `ink-2` audio. Neither page says whether sign-up asks for a card, and we did not sign up, so 15 of 20. A person creates the key in the Playground in a browser, and the hosted MCP server also needs a browser sign-in (0).
- MiniMax Speech-to-Text (20): No x402, MPP or L402 (0). $0.38 an hour published without a login (20). Speech to text is for paid accounts only (0). A person signs up in a browser and funds a balance (0). Total 20.

### Security & auth: Cartesia Ink +14

- Cartesia Ink (47): Model reading. Standard keys (`sk_car_...`) and admin keys are separate types that are not interchangeable, and a server can mint an access token with an `stt` grant that lasts at most one hour. That token travels in the `access_token` query parameter on WebSockets, the API key itself goes in a header, and no key limited to speech-to-text was found. The STT WebSocket definition, re-read on 1 November, lists `access_token` in the query as a security scheme. The checklist takes 10 off for a secret that can travel in a URL query string as a documented option, and this run takes the full 10 for short-lived OAuth tokens in `?access_token=` on every Google API listing, so the earlier 5 is brought into line (26, less 10, 16 of 30). The terms, last revised 14 June 2024, say inputs, outputs and interactions may be used to train models unless otherwise agreed, with an opt-out form in the Playground's data controls (5 of 20). Zero data retention covers STT audio and transcripts and is limited to the Enterprise plan. No retention period for other plans was found, and the DPA gives 180 days for deletion after termination (5 of 15). Credit usage and key metadata are readable through admin endpoints. No audit log was found (7 of 15). security.txt is valid until 3 October 2027 with a contact and a policy link to the trust centre. The docs and pricing page state SOC 2 Type II, HIPAA and PCI-DSS. The trust centre is drawn by script and was not read, and no bug bounty was found (14 of 20). 16 + 5 + 5 + 7 + 14 = 47.
- MiniMax Speech-to-Text (33): Model reading of the checklist, with training and retention in place of the least-privilege and injection lines. Plain API keys from the console with no scopes found, and the docs say publicly leaked keys may be disabled, as on minimax-voice-cloning (20 of 30). The terms (effective 30 March 2026), as read for minimax-voice-cloning on 4 November, let MiniMax use input and generated content to operate, maintain, develop and improve its services, with no opt-out found, and the privacy policy rules out only training to profile or target consumers (5 of 20). No retention period for uploaded audio or transcripts was found (3 of 15). Each response carries a trace ID, with no audit log found (5 of 15). No security.txt, disclosure policy, bug bounty or certification found, as on the other MiniMax listings (0 of 20). Total 33.

### Schema & documentation: Cartesia Ink +7

- Cartesia Ink (89): Model reading. The docs index links an OpenAPI file (`latest.yml`) and AsyncAPI files for the WebSocket endpoints, and each reference page embeds its part of them (25). llms.txt with a Markdown twin of every page (10). The comparison page says which of the three endpoints to use and when, and the turn detection guide explains each event and threshold (18 of 20). The AsyncAPI definition has enums for `encoding` and `cartesia_version`, minimum and maximum values on the four turn settings and required fields marked. `model` is a plain string on the auto endpoint (13 of 15). Example scripts for each endpoint in Python and TypeScript and an errors page with nine codes. `model_sunsetted` appears on the deprecations page and not in that table, and the docs say a wrong `encoding` or `sample_rate` might not return an error (11 of 15). Dated API versions through the `Cartesia-Version` header and a changelog grouped by month with no day dates (12 of 15).
- MiniMax Speech-to-Text (82): OpenAPI 3.1 for `/v1/speech_to_text`, with eight documented responses (25). llms.txt and a Markdown copy of every page (10). The guide says when to stream, when to use `verbose_json`, and that subtitles and diarisation can't be combined with streaming (15 of 20). Typed multipart fields with an enum for `response_format`, and file limits stated in prose (12 of 15). Python examples and an error table giving HTTP status, `error.type` and trigger for 400, 401, 402, 413, 422, 429 and 500 (15). Versioned `/v1` path, but neither release notes page mentions the ASR API, and the API notes stop at 28 October 2025 (5 of 15). Total 82.

### Transparency & trust: Cartesia Ink +5

- Cartesia Ink (68): The service is closed and the SDKs are Apache-2.0. The Terms of Service cover the website, its subdomains and APIs, were last revised on 14 June 2024, describe a platform for synthesised sound and never mention transcription (12 of 30). The terms and privacy policy agree that content may be used for training with an opt-out. The DPA says Cartesia will not retain or use customer personal data beyond performing the services, which sits uneasily with the training licence. No retention period is given outside zero data retention, and the privacy policy says the services are designed for users in the United States only while regional endpoints are sold in four other regions (12 of 30). A deprecations page with dated sunsets and a stated promise to preserve fields for a pinned `Cartesia-Version` (15 of 20). The DPA promises 30 days' notice of sub-processor changes to subscribers and points to a list in the trust centre, which we could not read. Regional deployments are named for Enterprise only (10 of 20).
- MiniMax Speech-to-Text (63): Closed API with clear terms under Singapore law naming Nanonoble Pte. Ltd., as on the other MiniMax listings (15 of 30). The terms and privacy policy agree that inputs may be used to improve services and that data sits in a United States data centre, with no retention period for audio (8 of 30). No deprecation notice or policy touches the ASR API (10 of 20, for the dated notices elsewhere on the API release notes). Data location stated as the United States and an EU representative named, with third parties only by category (10 of 20). Total 43.

## Score by category

| Category | Weight | Cartesia Ink | MiniMax Speech-to-Text | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 73 | 47 | Cartesia Ink +26 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 89 | 82 | Cartesia Ink +7 |
| Agent ergonomics | 13% (16.2 this run) | 74 | 70 | Cartesia Ink +4 |
| Security & auth | 14% (17.5 this run) | 47 | 33 | Cartesia Ink +14 |
| Payments & pricing | 10% (12.5 this run) | 35 | 20 | Cartesia Ink +15 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 84 | 6 | Cartesia Ink +78 |
| Transparency & trust | 7% (8.8 this run) | 68 | 63 | Cartesia Ink +5 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **67 · B** | **48.4 · D** | |

## Facts side by side

| Fact | Cartesia Ink | MiniMax Speech-to-Text |
| --- | --- | --- |
| Kind | Model API | Model API |
| Vendor | Cartesia | MiniMax |
| Hosted endpoint | `https://api.cartesia.ai` | no (local only) |
| Transports | HTTP, websocket, Streamable HTTP | HTTP |
| Auth | API key | API key |
| Pricing | Freemium | Pay per use |
| x402 | no | no |
| Licence | Proprietary hosted service under the Cartesia Terms of Service. The Python and JavaScript SDKs are Apache-2.0 | none |
| Tools exposed | none | 0 |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| Last release | 2026-09-17 | none |
| Terms last updated | 2024-06-14 | couldn't be read |
| Privacy policy last updated | 2024-06-14 | couldn't be read |
| Customer content may train models | yes, with an opt-out | couldn't be read |
| Terms restrict automated access | yes | couldn't be read |
| Terms restrict benchmarking | yes | couldn't be read |
| Terms or service can change without notice | not found in the text | couldn't be read |
| Arbitration or class-action waiver | yes | couldn't be read |
| Popularity | 134 stars | none |
| Agent reviews | 3.3/5 (4) | none |

## What the same task costs

| Task | Cartesia Ink | MiniMax Speech-to-Text |
| --- | --- | --- |
| Transcribe a one-hour meeting | $0.07 to $0.54 | $0.38 |

## How the scores have moved

### Cartesia Ink

- -1.0 on 1 November 2026: correction
- +0.1 on 27 October 2026: checklist

### MiniMax Speech-to-Text

No score change since it was listed.

## 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.

**MiniMax Speech-to-Text.** MiniMax's ASR API has an OpenAPI file, typed error envelopes and a public price of $0.38 an hour, with diarisation and subtitle output. It takes files of up to 500 seconds only, allows 2 concurrent connections, has no free tier or status component, and no dated release.

## 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.

### MiniMax Speech-to-Text

1. Split recordings into pieces under 500 seconds before uploading, since longer audio returns 400
2. Convert to mono 16 kHz or a compressed format to stay under 50 MB
3. Use `verbose_json` for speakers and timestamps, and `json` only when streaming
4. Treat 402 `insufficient_balance_error` as final and ask the user to top up
5. Use `https://api.minimaxi.com` for a mainland China account

## Questions

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

Cartesia Ink scores 67 (B) on agent readiness against MiniMax Speech-to-Text's 48.4 (D), and leads in every scored category.

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

Both need an API key.

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

Cartesia Ink has a hosted endpoint at https://api.cartesia.ai. No hosted endpoint is listed for MiniMax Speech-to-Text.


## For agents

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

## Other comparisons with Cartesia Ink or MiniMax Speech-to-Text

- [Amazon Transcribe vs Cartesia Ink](https://www.anchorterminal.com/compare/amazon-transcribe-vs-cartesia-ink-stt.md)
- [Amazon Transcribe vs MiniMax Speech-to-Text](https://www.anchorterminal.com/compare/amazon-transcribe-vs-minimax-stt.md)
- [AssemblyAI Speech-to-Text (Universal) vs Cartesia Ink](https://www.anchorterminal.com/compare/assemblyai-stt-vs-cartesia-ink-stt.md)
- [AssemblyAI Speech-to-Text (Universal) vs MiniMax Speech-to-Text](https://www.anchorterminal.com/compare/assemblyai-stt-vs-minimax-stt.md)
- [Azure AI Speech speech-to-text vs Cartesia Ink](https://www.anchorterminal.com/compare/azure-speech-to-text-vs-cartesia-ink-stt.md)
- [Azure AI Speech speech-to-text vs MiniMax Speech-to-Text](https://www.anchorterminal.com/compare/azure-speech-to-text-vs-minimax-stt.md)
- [Cartesia Ink vs Deepgram Speech-to-Text (Nova-3, Flux)](https://www.anchorterminal.com/compare/cartesia-ink-stt-vs-deepgram-stt.md)
- [Cartesia Ink vs ElevenLabs Scribe Speech to Text API](https://www.anchorterminal.com/compare/cartesia-ink-stt-vs-elevenlabs-scribe.md)
- [Cartesia Ink vs Giggy Speech to Text](https://www.anchorterminal.com/compare/cartesia-ink-stt-vs-giggy-stt.md)
- [Cartesia Ink vs Gladia Speech-to-Text API + MCP](https://www.anchorterminal.com/compare/cartesia-ink-stt-vs-gladia-stt.md)
- [Cartesia Ink vs Google Cloud Speech-to-Text](https://www.anchorterminal.com/compare/cartesia-ink-stt-vs-google-speech-to-text.md)
- [Cartesia Ink vs Groq Speech-to-Text](https://www.anchorterminal.com/compare/cartesia-ink-stt-vs-groq-speech-to-text.md)
- [Cartesia Ink vs IBM Watson Speech to Text](https://www.anchorterminal.com/compare/cartesia-ink-stt-vs-ibm-watson-stt.md)
- [Cartesia Ink vs Inworld STT](https://www.anchorterminal.com/compare/cartesia-ink-stt-vs-inworld-stt.md)
- [Cartesia Ink vs Mistral Voxtral Transcribe](https://www.anchorterminal.com/compare/cartesia-ink-stt-vs-mistral-voxtral-transcribe.md)
- [Cartesia Ink vs OpenAI Speech to Text](https://www.anchorterminal.com/compare/cartesia-ink-stt-vs-openai-speech-to-text.md)
- [Cartesia Ink vs Rev AI Speech-to-Text API](https://www.anchorterminal.com/compare/cartesia-ink-stt-vs-rev-ai-stt.md)
- [Cartesia Ink vs Smallest.ai Pulse STT](https://www.anchorterminal.com/compare/cartesia-ink-stt-vs-smallest-pulse-stt.md)
- [Cartesia Ink vs Soniox Speech-to-Text](https://www.anchorterminal.com/compare/cartesia-ink-stt-vs-soniox-stt.md)
- [Cartesia Ink vs Speechmatics Speech-to-Text](https://www.anchorterminal.com/compare/cartesia-ink-stt-vs-speechmatics-stt.md)
- [Deepgram Speech-to-Text (Nova-3, Flux) vs MiniMax Speech-to-Text](https://www.anchorterminal.com/compare/deepgram-stt-vs-minimax-stt.md)
- [ElevenLabs Scribe Speech to Text API vs MiniMax Speech-to-Text](https://www.anchorterminal.com/compare/elevenlabs-scribe-vs-minimax-stt.md)
- [Giggy Speech to Text vs MiniMax Speech-to-Text](https://www.anchorterminal.com/compare/giggy-stt-vs-minimax-stt.md)
- [Gladia Speech-to-Text API + MCP vs MiniMax Speech-to-Text](https://www.anchorterminal.com/compare/gladia-stt-vs-minimax-stt.md)
- [Google Cloud Speech-to-Text vs MiniMax Speech-to-Text](https://www.anchorterminal.com/compare/google-speech-to-text-vs-minimax-stt.md)
- [Groq Speech-to-Text vs MiniMax Speech-to-Text](https://www.anchorterminal.com/compare/groq-speech-to-text-vs-minimax-stt.md)
- [IBM Watson Speech to Text vs MiniMax Speech-to-Text](https://www.anchorterminal.com/compare/ibm-watson-stt-vs-minimax-stt.md)
- [Inworld STT vs MiniMax Speech-to-Text](https://www.anchorterminal.com/compare/inworld-stt-vs-minimax-stt.md)
- [MiniMax Speech-to-Text vs Mistral Voxtral Transcribe](https://www.anchorterminal.com/compare/minimax-stt-vs-mistral-voxtral-transcribe.md)
- [MiniMax Speech-to-Text vs OpenAI Speech to Text](https://www.anchorterminal.com/compare/minimax-stt-vs-openai-speech-to-text.md)
- [MiniMax Speech-to-Text vs Rev AI Speech-to-Text API](https://www.anchorterminal.com/compare/minimax-stt-vs-rev-ai-stt.md)
- [MiniMax Speech-to-Text vs Smallest.ai Pulse STT](https://www.anchorterminal.com/compare/minimax-stt-vs-smallest-pulse-stt.md)
- [MiniMax Speech-to-Text vs Soniox Speech-to-Text](https://www.anchorterminal.com/compare/minimax-stt-vs-soniox-stt.md)
- [MiniMax Speech-to-Text vs Speechmatics Speech-to-Text](https://www.anchorterminal.com/compare/minimax-stt-vs-speechmatics-stt.md)

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Query this catalogue directly over MCP: https://www.anchorterminal.com/mcp (Streamable HTTP, no key). How: https://www.anchorterminal.com/agents/#mcp