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

Mistral Voxtral Transcribe vs OpenAI Speech to Text

OpenAI Speech to Text scores 72.4 (BB) on agent readiness against Mistral Voxtral Transcribe's 64.1 (B), and leads in 5 of 7 scored categories. Mistral Voxtral Transcribe leads on payments & pricing and transparency & trust. Both do speech-to-text.

Best speech-to-text APIs for AI agents · All 91 stt comparisons

Mistral Voxtral TranscribeMistral AI · Model API B64.1/100#365 of 950 OpenAI Speech to TextOpenAI · Model API BB72.4/100#106 of 950

Which one, for what

Mistral Voxtral Transcribe B

Good for Suited to low-cost batch transcription with diarisation in the 13 supported languages, and to live captions or voice agents that can run without speaker labels.

Ahead on

  • Payments & pricing, 40 against 20
  • Transparency & trust, 82 against 61

Watch for

Audio rate limits are named (audio seconds a minute and a month) but the numbers are shown only in the Admin Panel

OpenAI Speech to Text BB

Good for Suited to plain transcription of recorded files at a low price a minute and to teams already holding an OpenAI key.

Ahead on

  • Reliability, 80 against 53
  • Security & auth, 86 against 70
  • Maintenance & community, 75 against 66

Also in its favour

  • Agent-ready, a grade of BB or better
  • No incidents deducted, where Mistral Voxtral Transcribe loses 3 points for them

Watch for

whisper-1, gpt-4o-transcribe, gpt-4o-mini-transcribe and gpt-4o-transcribe-diarize were deprecated on 26 August 2026 and shut down on 26 February 2027

Score by category

CategoryWeight this runMistral Voxtral TranscribeOpenAI Speech to TextEdge
Reliability16%205380OpenAI Speech to Text +27
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.28588OpenAI Speech to Text +3
Agent ergonomics13%16.27778OpenAI Speech to Text +1
Security & auth14%17.57086OpenAI Speech to Text +16
Payments & pricing10%12.54020Mistral Voxtral Transcribe +20
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.86675OpenAI Speech to Text +9
Transparency & trust7%8.88261Mistral Voxtral Transcribe +21
Negative events≤15-30
Total64.1 · B72.4 · BB

Facts side by side

FactMistral Voxtral TranscribeOpenAI Speech to Text
KindModel APIModel API
VendorMistral AIOpenAI
Hosted endpointhttps://api.mistral.ai/v1https://api.openai.com/v1
TransportsHTTP, websocketHTTP, websocket
AuthAPI keyAPI key
PricingFreemiumPay per use
x402nono
LicenceProprietary hosted service under Mistral's commercial terms. Voxtral Mini 4B Realtime weights and the SDKs are Apache-2.0Proprietary hosted service. The service terms were not read (see open questions). The Python SDK is Apache-2.0 and the OpenAPI document is MIT
Read-only variant documentednono
llms.txtyesyes
Last release2026-02-042026-08-26
Terms last updated2026-09-25couldn't be read
Privacy policy last updated2026-09-03couldn't be read
Customer content may train modelsyes, with an opt-outcouldn't be read
Terms restrict automated accessnot found in the textcouldn't be read
Terms restrict benchmarkingyescouldn't be read
Terms or service can change without noticeyescouldn't be read
Arbitration or class-action waivernot found in the textcouldn't be read
Popularity773 stars32k stars

Verdicts

Mistral Voxtral Transcribe

Batch transcription costs $0.003 a minute and takes one multipart call with a file, a URL or an uploaded file ID. Rate limit numbers are shown only in the console, and timestamps cannot be combined with a set language, nor diarisation with the realtime model.

OpenAI Speech to Text

gpt-transcribe costs $0.0045 an audio minute, and the audio endpoints keep no abuse-monitoring logs or application state. Speaker labels, timestamps, subtitles and translation exist only on whisper-1 and gpt-4o-transcribe-diarize, which shut down on 26 February 2027 with no named replacement for those functions.

Before you call either

Mistral Voxtral Transcribe

  1. Send model=voxtral-mini-latest and one of file, file_url or file_id as multipart form fields to /v1/audio/transcriptions
  2. Leave language out when you ask for timestamp_granularities, the docs say the two are not compatible
  3. Use the batch endpoint for diarisation. voxtral-mini-transcribe-realtime-2602 does not accept diarize
  4. Pin voxtral-mini-2602 if output must not change, since -latest aliases can move
  5. Mint browser tokens with POST /v1/client/sessions close to connection time and pass them in Sec-WebSocket-Protocol, never the API key

OpenAI Speech to Text

  1. Send gpt-transcribe to POST /v1/audio/transcriptions for recorded files. Use languages (a list), not language, and never send both.
  2. Keep each upload at 25 MB or less. Split longer audio between sentences and pass the previous chunk's text in prompt.
  3. For speaker labels send gpt-4o-transcribe-diarize with response_format=diarized_json and chunking_strategy=auto for audio over 30 seconds. Plan for its shutdown on 26 February 2027.
  4. Word timestamps, srt, vtt and /v1/audio/translations need whisper-1, which cannot stream and shuts down on the same date.
  5. On 429 or 503 wait at least Retry-After when present, then back off with jitter. Do not retry credit_balance_exhausted or spend-limit errors.

Questions

Which is better for AI agents, Mistral Voxtral Transcribe or OpenAI Speech to Text?

OpenAI Speech to Text scores 72.4 (BB) on agent readiness against Mistral Voxtral Transcribe's 64.1 (B), and leads in 5 of 7 scored categories. Mistral Voxtral Transcribe leads on payments & pricing and transparency & trust.

Do Mistral Voxtral Transcribe and OpenAI Speech to Text need an API key?

Both need an API key.

Can an agent call Mistral Voxtral Transcribe and OpenAI Speech to Text without installing anything?

Yes. Mistral Voxtral Transcribe has a hosted endpoint at https://api.mistral.ai/v1 and OpenAI Speech to Text at https://api.openai.com/v1.

Other comparisons with Mistral Voxtral Transcribe or OpenAI Speech to Text

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