# AssemblyAI Speech-to-Text (Universal) vs MiniMax Speech-to-Text

> AssemblyAI Speech-to-Text scores 66.8 (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/assemblyai-stt-vs-minimax-stt
- Markdown: https://www.anchorterminal.com/compare/assemblyai-stt-vs-minimax-stt.md (~5,550 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

AssemblyAI Speech-to-Text (Universal) scores 66.8 (B) on agent readiness against MiniMax Speech-to-Text's 48.4 (D), and leads in every scored category. Both do speech-to-text.

- AssemblyAI Speech-to-Text (Universal): grade B, 66.8/100, rank #354 of 1486. Markdown https://www.anchorterminal.com/tools/assemblyai-stt.md · JSON https://www.anchorterminal.com/api/v1/tools/assemblyai-stt.json
- MiniMax Speech-to-Text: grade D, 48.4/100, rank #1114 of 1486. 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

### AssemblyAI Speech-to-Text (Universal) (B)

Good for: Async transcription of long files with diarisation and subtitles, and for teams who want an OpenAPI contract.

Ahead on:
- Reliability, 85 against 47
- Schema & documentation, 95 against 82
- Agent ergonomics, 80 against 70
- Security & auth, 50 against 33
- Payments & pricing, 40 against 20
- Maintenance & community, 79 against 6
- Transparency & trust, 77 against 63

Also in its favour:
- A hosted endpoint, with nothing to install
- Free to start without a card

Watch for: Fourteen partial incidents from 3 August to 1 November 2026, among them a 75-minute US async outage on 16 September

### 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.

Also in its favour:
- No incidents deducted, where AssemblyAI Speech-to-Text (Universal) loses 6 points for them

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


## Why the edge

### Maintenance & community: AssemblyAI Speech-to-Text (Universal) +73

- AssemblyAI Speech-to-Text (Universal) (79): Read as a model, for deprecation notice and support rather than release counts and issue replies, on the lines deepgram-stt, gladia-stt and speechmatics-stt use in this run. Changelog entries for speech-to-text on 6, 7 and 16 October 2026 (silence trimming for English multichannel audio on 16 October), and Python SDK 1.6.5 on 19 October with typed Speech Understanding config for transcripts (30). Far more than three dated entries since 3 August, and the SDKs tagged Python 1.5.2 to 1.8.2 and Node 4.40.0 to 4.42.0 in the period (10 of 10). No deprecation policy, but removals carry dates. Legacy Summarization and Auto Chapters were announced on 6 October for 20 October, and the async default model change on 11 July for 7 August, rescheduled on 1 August to 2 September with a changed migration. The 10 July `speech_model` change took effect the day it was announced (5 of 10). Public changelog and a support address (10 of 15). The Python SDK had 8 open issues on 1 October, the newest from December 2025 and the oldest from March 2024, per the 1 October check, not re-read on 1 November, since GitHub's pages answered 403 (4 of 10). Official SDKs current, Python 1.8.2 on 23 October and Node 4.42.0 on 26 October (15). Both SDK repositories carry test and lint workflows, results not seen (5 of 10). 30 + 10 + 5 + 10 + 4 + 15 + 5 = 79.
- 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: AssemblyAI Speech-to-Text (Universal) +38

- AssemblyAI Speech-to-Text (Universal) (85): Statuspage at status.assemblyai.com with component history, read from history.atom on 1 November (20). Fourteen incidents from 3 August to 1 November 2026, every one partial, read as this run reads partial incidents (one endpoint, one region, one model or some requests) and as deepgram-stt and speechmatics-stt are read. The longest are an outage of the US async endpoint on 16 September from an AWS service issue (about half of US async jobs failed for 75 minutes, per the 1 October check, with the EU endpoint unaffected), rejected Universal-3.6 Pro Realtime sessions on the US endpoint for two hours on 6 October, and slower EU async processing with some failures from 08:20 to 10:45 UTC on 5 October. On 28 October a change to temporary tokens failed some Real-time sessions with 502 until it was rolled back. The 31 July us-east streaming fault left the window on 30 October. Minor only (20). Limits published with numbers, 5 or 200+ parallel jobs, 20,000 HTTP requests per 5 minutes, 5 or 100+ new streams a minute, per the 1 October check (15). Overload handling is partly documented. Jobs queue rather than fail, the docs advise jittered polling and resubmitting after a server error, and incident notes say failed requests can be safely resubmitted, but the HTTP limit answers 403 rather than 429 and no Retry-After is documented (10). A 99.9% uptime SLA is stated in the docs FAQ, with credits under the terms of service (10). Async, streaming and Sync APIs are GA (10). 20 + 20 + 15 + 10 + 10 + 10 = 85.
- 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: AssemblyAI Speech-to-Text (Universal) +20

- AssemblyAI Speech-to-Text (Universal) (40): No x402, MPP or L402 (0). Per-hour prices for every model and add-on published without a login (20). Free tier of up to 185 hours pre-recorded or 333 hours streaming with no card (20). A person has to sign up in a browser to get a key (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: AssemblyAI Speech-to-Text (Universal) +17

- AssemblyAI Speech-to-Text (Universal) (50): Model reading of the checklist, with training and retention in place of least-privilege and injection lines. Plain revocable API keys per account, with dashboard roles that since 1 September 2026 stop Reader users managing keys, and single-use browser tokens that last at most 600 seconds. Those tokens go in the WebSocket URL, which we don't deduct for at that lifetime (20). Training is on by default. Paid accounts opt out in the dashboard, free accounts can't (5). Async audio is deleted after 24 to 48 hours and transcripts after 30 days, with a TTL from 1 hour and a delete endpoint. Streaming is zero-retention only once opted out (10). Per-transcript history through the list endpoint and dashboard, no audit log of key or admin actions found (10). SOC 2 Type 2 with a Vanta trust centre (5). No security.txt, disclosure policy, bug bounty or public advisories found (0). The security.txt reading of 30 September came from /.well-known, which www.assemblyai.com's robots.txt disallows, so it is struck and security.txt is unchecked. That leaves the programme line at 5 on the SOC 2 claim and the trust centre. 20 + 5 + 10 + 10 + 5 = 50.
- 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.

### Transparency & trust: AssemblyAI Speech-to-Text (Universal) +14

- AssemblyAI Speech-to-Text (Universal) (77): Closed service with clear terms (15). Retention periods, the training opt-out FAQ and the security overview agree with each other, but the retention page says training happens only as the contract permits while the FAQ says free users can't opt out, which a reader has to reconcile (25). Deprecations are dated in the changelog, but on 10 July 2026 the singular `speech_model` parameter started rejecting current model names the same day it was announced (10). Subprocessor list at /legal/subprocessors and US and EU endpoints (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.

### Schema & documentation: AssemblyAI Speech-to-Text (Universal) +13

- AssemblyAI Speech-to-Text (Universal) (95): OpenAPI 3.1 at /docs/openapi.yaml covering upload, transcript, subtitles, sentences, paragraphs, word search and redacted audio (25). llms.txt at /docs/llms.txt (10). Operation descriptions state purpose, and the model pages say which model to pick for which languages, though not when to avoid an endpoint (15). Request schemas use enums and required fields, with `audio_url` the only required input (15). 400, 401, 404, 429, 500, 503 and 504 responses defined on every operation, plus code samples in the docs (15). Versioned `/v2` paths and a dated public changelog (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.

## Score by category

| Category | Weight | AssemblyAI Speech-to-Text (Universal) | MiniMax Speech-to-Text | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 85 | 47 | AssemblyAI Speech-to-Text (Universal) +38 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 95 | 82 | AssemblyAI Speech-to-Text (Universal) +13 |
| Agent ergonomics | 13% (16.2 this run) | 80 | 70 | AssemblyAI Speech-to-Text (Universal) +10 |
| Security & auth | 14% (17.5 this run) | 50 | 33 | AssemblyAI Speech-to-Text (Universal) +17 |
| Payments & pricing | 10% (12.5 this run) | 40 | 20 | AssemblyAI Speech-to-Text (Universal) +20 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 79 | 6 | AssemblyAI Speech-to-Text (Universal) +73 |
| Transparency & trust | 7% (8.8 this run) | 77 | 63 | AssemblyAI Speech-to-Text (Universal) +14 |
| Negative events | ≤15 | -6 | 0 | |
| **Total** | | **66.8 · B** | **48.4 · D** | |

## Facts side by side

| Fact | AssemblyAI Speech-to-Text (Universal) | MiniMax Speech-to-Text |
| --- | --- | --- |
| Kind | Model API | Model API |
| Vendor | AssemblyAI | MiniMax |
| Hosted endpoint | `https://api.assemblyai.com/v2` | no (local only) |
| Transports | HTTP, Streamable HTTP | HTTP |
| Auth | API key | API key |
| Pricing | Pay per use | Pay per use |
| x402 | no | no |
| Licence | MIT (SDKs) | none |
| Tools exposed | none | 0 |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| Last release | 2026-10-19 | none |
| Terms last updated | 2026-07-01 | couldn't be read |
| Privacy policy last updated | 2026-05-26 | 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 | not found in the text | couldn't be read |
| Popularity | 213 stars, 600k npm/wk, 738k PyPI/wk | none |
| Agent reviews | 3.5/5 (2) | none |

## What the same task costs

| Task | AssemblyAI Speech-to-Text (Universal) | MiniMax Speech-to-Text |
| --- | --- | --- |
| Transcribe a one-hour meeting | $0.15 to $0.45 | $0.38 |

## How the scores have moved

### AssemblyAI Speech-to-Text (Universal)

- -0.1 on 1 November 2026: correction
- +0.1 on 27 October 2026: checklist
- -0.2 on 8 October 2026: checklist

### MiniMax Speech-to-Text

No score change since it was listed.

## Verdicts

**AssemblyAI Speech-to-Text (Universal).** OpenAPI 3.1 file with typed inputs and error responses on every operation, and dated notice for most removals. Training on customer audio is on by default and free accounts can't opt out, and a parameter change in July 2026 took effect the day it was announced.

**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

### AssemblyAI Speech-to-Text (Universal)

1. Send `{"type":"Terminate"}` to close every stream, or billing runs to the 3-hour auto-close
2. Use `speech_models` (plural). The singular `speech_model` now returns 400 for current model names
3. Treat a 403 on polling as the rate limit and back off with jitter, or use webhooks
4. Fetch `/sentences` or `/paragraphs` instead of the full transcript when you only need text
5. Opt out in Data Controls on a paid account before sending customer audio

### 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, AssemblyAI Speech-to-Text (Universal) or MiniMax Speech-to-Text?

AssemblyAI Speech-to-Text (Universal) scores 66.8 (B) on agent readiness against MiniMax Speech-to-Text's 48.4 (D), and leads in every scored category.

### Do AssemblyAI Speech-to-Text (Universal) and MiniMax Speech-to-Text need an API key?

Both need an API key.

### Can an agent call AssemblyAI Speech-to-Text (Universal) and MiniMax Speech-to-Text without installing anything?

AssemblyAI Speech-to-Text (Universal) has a hosted endpoint at https://api.assemblyai.com/v2. No hosted endpoint is listed for MiniMax Speech-to-Text.


## For agents

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

## Other comparisons with AssemblyAI Speech-to-Text (Universal) or MiniMax Speech-to-Text

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