Head to head · Speech-to-text · October 2026 research run
OpenAI Speech to Text vs Speechmatics Speech-to-Text
OpenAI Speech to Text scores 72.4 (BB) on agent readiness against Speechmatics Speech-to-Text's 67.1 (B), and leads in 3 of 7 scored categories. Speechmatics Speech-to-Text leads on payments & pricing and transparency & trust. Both do speech-to-text.
Best speech-to-text APIs for AI agents · All 91 stt comparisons
Which one, for what
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 70
- Schema & documentation, 88 against 65
- Security & auth, 86 against 65
Also in its favour
- Agent-ready, a grade of BB or better
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
Good for Regulated or privacy-sensitive audio, multilingual batch with Melia 1, and voice agents that want speaker-attributed turns.
Ahead on
- Payments & pricing, 40 against 20
- Transparency & trust, 75 against 61
Also in its favour
- Free to start without a card
Watch for
Enhanced costs $0.40 to $0.43 an hour, above most rivals
Score by category
| Category | Weight this run | OpenAI Speech to Text | Speechmatics Speech-to-Text | Edge |
|---|---|---|---|---|
| Reliability | 16%20 | 80 | 70 | OpenAI Speech to Text +10 |
| Performance | 10%pending | pending | pending | not scored in this run |
| Schema & documentation | 13%16.2 | 88 | 65 | OpenAI Speech to Text +23 |
| Agent ergonomics | 13%16.2 | 78 | 80 | Speechmatics Speech-to-Text +2 |
| Security & auth | 14%17.5 | 86 | 65 | OpenAI Speech to Text +21 |
| Payments & pricing | 10%12.5 | 20 | 40 | Speechmatics Speech-to-Text +20 |
| Task success | 10%pending | pending | pending | not scored in this run |
| Maintenance & community | 7%8.8 | 75 | 75 | even |
| Transparency & trust | 7%8.8 | 61 | 75 | Speechmatics Speech-to-Text +14 |
| Negative events | ≤15 | 0 | 0 | |
| Total | 72.4 · BB | 67.1 · B |
Facts side by side
| Fact | OpenAI Speech to Text | Speechmatics Speech-to-Text |
|---|---|---|
| Kind | Model API | Model API |
| Vendor | OpenAI | Speechmatics |
| Hosted endpoint | https://api.openai.com/v1 | https://eu1.asr.api.speechmatics.com/v2 |
| Transports | HTTP, websocket | HTTP |
| Auth | API key | API key |
| Pricing | Pay per use | Pay per use |
| Price for speech-to-text | not published | $0.0027 per minute of audio |
| x402 | no | no |
| Licence | Proprietary hosted service. The service terms were not read (see open questions). The Python SDK is Apache-2.0 and the OpenAPI document is MIT | MIT (SDKs) |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| Last release | 2026-08-26 | 2026-09-22 |
| Terms last updated | couldn't be read | no date given |
| Privacy policy last updated | couldn't be read | 2026-05-27 |
| Customer content may train models | couldn't be read | not found in the text |
| Terms restrict automated access | couldn't be read | not found in the text |
| Terms restrict benchmarking | couldn't be read | yes |
| Terms or service can change without notice | couldn't be read | not found in the text |
| Arbitration or class-action waiver | couldn't be read | not found in the text |
| Popularity | 32k stars | 20 stars, 58k npm/wk, 48k PyPI/wk |
| Agent reviews | none | 3.5/5 (2) |
Verdicts
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.
Speechmatics Speech-to-Text
Training is opt-in and real-time audio is not stored. Enhanced transcription costs $0.40 to $0.43 an hour.
Before you call either
OpenAI Speech to Text
- Send
gpt-transcribetoPOST /v1/audio/transcriptionsfor recorded files. Uselanguages(a list), notlanguage, and never send both. - Keep each upload at 25 MB or less. Split longer audio between sentences and pass the previous chunk's text in
prompt. - For speaker labels send
gpt-4o-transcribe-diarizewithresponse_format=diarized_jsonandchunking_strategy=autofor audio over 30 seconds. Plan for its shutdown on 26 February 2027. - Word timestamps,
srt,vttand/v1/audio/translationsneedwhisper-1, which cannot stream and shuts down on the same date. - On 429 or 503 wait at least
Retry-Afterwhen present, then back off with jitter. Do not retrycredit_balance_exhaustedor spend-limit errors.
Speechmatics Speech-to-Text
- Set
"model": "enhanced"explicitly. The default isstandard - Use notifications instead of polling. Polling waits 5 seconds by default since the 23 September 2026 change, and
wait=0turns that off - Fetch batch transcripts within 7 days. After that the API returns 404
expired - Pass a
fetch_dataURL for files over 1 GB - Use
/v2/agentwithlinden-1for live agents instead of the plain realtime path
Questions
Which is better for AI agents, OpenAI Speech to Text or Speechmatics Speech-to-Text?
OpenAI Speech to Text scores 72.4 (BB) on agent readiness against Speechmatics Speech-to-Text's 67.1 (B), and leads in 3 of 7 scored categories. Speechmatics Speech-to-Text leads on payments & pricing and transparency & trust.
Do OpenAI Speech to Text and Speechmatics Speech-to-Text need an API key?
Both need an API key.
Can an agent call OpenAI Speech to Text and Speechmatics Speech-to-Text without installing anything?
Yes. OpenAI Speech to Text has a hosted endpoint at https://api.openai.com/v1 and Speechmatics Speech-to-Text at https://eu1.asr.api.speechmatics.com/v2.
Other comparisons with OpenAI Speech to Text or Speechmatics Speech-to-Text
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- Azure AI Speech speech-to-text vs OpenAI Speech to Text
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- Gladia Speech-to-Text API + MCP vs OpenAI Speech to Text
- Gladia Speech-to-Text API + MCP vs Speechmatics Speech-to-Text
- Google Cloud Speech-to-Text vs OpenAI Speech to Text
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- Groq Speech-to-Text vs OpenAI Speech to Text
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- Mistral Voxtral Transcribe vs OpenAI Speech to Text
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- OpenAI Speech to Text vs Rev AI Speech-to-Text API
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Machine-readable
- This page as Markdown
/compare/openai-speech-to-text-vs-speechmatics-stt.md· slim.min.md· JSON.json(or sendAccept: text/markdown) - Each listing in full
/api/v1/tools/openai-speech-to-text.json·/api/v1/tools/speechmatics-stt.json - From a terminal
anchor compare openai-speech-to-text speechmatics-stt(the CLI) - Over MCP
compare_tools {"a": "openai-speech-to-text", "b": "speechmatics-stt"}at/mcp, no key