Head to head · Speech-to-text · October 2026 research run

IBM Watson Speech to Text vs MiniMax Speech-to-Text

IBM Watson Speech to Text scores 54.5 (C) on agent readiness against MiniMax Speech-to-Text's 48.4 (D), and leads in 4 of 7 scored categories. MiniMax Speech-to-Text leads on reliability and schema & documentation. Both do speech-to-text.

Best speech-to-text APIs for AI agents · All 320 stt comparisons

Which one, for what

IBM Watson Speech to Text C

Best for Enterprises on IBM Cloud needing custom acoustic models, HIPAA on Premium and many locations.

Ahead on

  • Security & auth, 68 against 33
  • Payments & pricing, 40 against 20
  • Maintenance & community, 33 against 6
  • Transparency & trust, 80 against 63

Watch for

No public OpenAPI file or llms.txt

MiniMax Speech-to-Text D

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

Ahead on

  • Reliability, 47 against 40
  • Schema & documentation, 82 against 55

Watch for

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

Why the edge

Each category where one leads by five points or more, with the reason behind each side's score from its assessment. The numbers are in the table below; this is what they stand for.

Security & auth IBM Watson Speech to Text +35

IBM Watson Speech to Text 68

Model reading of the checklist, with training and retention in place of the least-privilege and injection lines. IAM API keys per instance with Reader, Writer and Manager roles and short-lived bearer tokens (30). The WebSocket interface takes the token as an access_token query parameter, so 10 off (20 of 30). Request and response data are logged by default to improve the service, and any account can opt out per account or per request (10 of 20). Async results expire after a week by default (results_ttl shortens it), a delete method exists, and DELETE /v1/user_data removes data by customer ID (10 of 15). Activity Tracker events record changes to the service's state (10 of 15). Valid security.txt to 6 December 2026, PSIRT and HackerOne, HIPAA readiness on Premium. Certifications weren't read (18 of 20). Total 68.

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 MiniMax Speech-to-Text +27

IBM Watson Speech to Text 55

No public OpenAPI or other machine-readable definition was found (0). No llms.txt (0). The reference says which parameters each model family supports and the docs cover each feature (15 of 20). Typed parameters with defaults, ranges and enums (13 of 15). curl and SDK examples on every method, and errors with error, code, code_description and warnings, with invalid arguments reported as warnings (12 of 15). Versioned /v1 paths and dated release notes back to 2015 (15). Total 55.

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.

Maintenance & community IBM Watson Speech to Text +27

IBM Watson Speech to Text 33

Read as a model. The newest release note is 29 June 2026 (parameter_set for large speech models), 130 days ago (10). No dated entries in the 90 days from 8 August (0). Release notes, IBM support and a public docs repository last changed 30 June 2026 (8 of 15). Official SDKs, ibm-watson 11.2.0 on PyPI (26 January 2026) and 12.2.0 on npm (January 2026) (10 of 15). CI not read (5 of 10). Total 33.

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.

Payments & pricing IBM Watson Speech to Text +20

IBM Watson Speech to Text 40

No x402, MPP or L402 (0). Per-minute Plus prices published in the docs without a login (20). The Lite plan gives 500 free minutes a month, and no page read says a card is needed (20). A person creates an IBM Cloud account and service instance in a browser (0). Total 40.

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.

Transparency & trust IBM Watson Speech to Text +17

IBM Watson Speech to Text 80

Closed service under the IBM Cloud terms (15). The data security page states default logging for improvement with an opt-out, async retention, GDPR deletion by customer ID and plan-level separation, and they agree with each other. The DPA wasn't read (20 of 30). Previous-generation models carried a dated deprecation of 15 March 2022 and removal on 31 July 2023, and release notes say changes are compatible unless noted (18 of 20). Ten locations are named, with sub-processors not read (12 of 20). Total 65.

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.

Reliability MiniMax Speech-to-Text +7

IBM Watson Speech to Text 40

IBM Cloud has a status page at cloud.ibm.com/status, but it is drawn by script and showed no components or history to our reader, read as gemini-live's script-shell page was (10 of 20, and 5 for no readable history). Plus allows up to 100 concurrent transcription requests across WebSocket and HTTP (15). No 429 or backoff guidance was found in the API reference or the docs repository (0). No SLA was read for the service (0, unchecked). Next-generation and large speech models are GA, language by language (10). 10 + 5 + 15 + 0 + 0 + 10 = 40.

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.

Score by category

CategoryWeight this runIBM Watson Speech to TextMiniMax Speech-to-TextEdge
Reliability16%204047MiniMax Speech-to-Text +7
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.25582MiniMax Speech-to-Text +27
Agent ergonomics13%16.26670MiniMax Speech-to-Text +4
Security & auth14%17.56833IBM Watson Speech to Text +35
Payments & pricing10%12.54020IBM Watson Speech to Text +20
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.8336IBM Watson Speech to Text +27
Transparency & trust7%8.88063IBM Watson Speech to Text +17
Negative events≤1500
TotalC 54.5/100D 48.4/100

Facts side by side

FactIBM Watson Speech to TextMiniMax Speech-to-Text
KindModel APIModel API
VendorIBMMiniMax
Hosted endpointno (local only)no (local only)
TransportsHTTP, websocketHTTP
AuthAPI keyAPI key
PricingFreemiumPay per use
x402nono
Tools exposed00
Read-only variant documentednono
llms.txtnoyes
Last release2026-06-29none
Terms last updatedno date givencouldn't be read
Privacy policy last updated2026-08-25couldn't be read
Customer content may train modelsnot found in the textcouldn't be read
Terms restrict automated accessnot found in the textcouldn't be read
Terms restrict benchmarkingnot found in the textcouldn't be read
Terms or service can change without noticenot found in the textcouldn't be read
Arbitration or class-action waivernot found in the textcouldn't be read

What the same task costs

TaskIBM Watson Speech to TextMiniMax Speech-to-Text
Transcribe a one-hour meeting60 minutes of recorded audio$0.60 to $1.20$0.38

Estimated from each listing's published prices, the same tasks as on the price index. Plans, minimums and free allowances aren't counted.

Verdicts

IBM Watson Speech to Text

Watson STT covers sync, async and WebSocket transcription in ten locations, with custom models, $0.02 a minute on Plus and 500 free minutes. There is no machine-readable spec or readable status history, requests are logged for improvement unless opted out, the WebSocket token goes in the URL, and the last release note is from June 2026.

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

IBM Watson Speech to Text

  1. Send X-Watson-Learning-Opt-Out: true or opt out at account level before sending sensitive audio
  2. Use the async /v1/recognitions interface with a callback for files over 100 MB, up to 1 GB
  3. Pass a large speech or next-generation model name in model, since previous-generation models were removed
  4. Tag requests with X-Watson-Metadata: customer_id=... so the data can be deleted later
  5. Keep within 100 concurrent requests on Plus across HTTP and WebSocket

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, IBM Watson Speech to Text or MiniMax Speech-to-Text?

IBM Watson Speech to Text scores 54.5 (C) on agent readiness against MiniMax Speech-to-Text's 48.4 (D), and leads in 4 of 7 scored categories. MiniMax Speech-to-Text leads on reliability and schema & documentation.

Do IBM Watson Speech to Text and MiniMax Speech-to-Text need an API key?

Both need an API key.

Can an agent call IBM Watson Speech to Text and MiniMax Speech-to-Text without installing anything?

No hosted endpoint is listed for IBM Watson Speech to Text. No hosted endpoint is listed for MiniMax Speech-to-Text.

Other comparisons with IBM Watson Speech to Text or MiniMax Speech-to-Text

Machine-readable

For companies

Do agents find, use and choose your tools?

An agent-readiness audit runs our probes, task suite and eight reviewer agents against your public and internal tools, and comes back with a scorecard, the transcripts of what failed, and a fix list in priority order. From $2,500, re-run included. We never take payment to move a rank. We do help companies earn one.