# OpenAI Speech to Text vs Speechmatics Speech-to-Text

> OpenAI Speech to Text scores 72.4 (BB) to Speechmatics Speech-to-Text's 67.1 (B) for speech-to-text. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/openai-speech-to-text-vs-speechmatics-stt
- Markdown: https://www.anchorterminal.com/compare/openai-speech-to-text-vs-speechmatics-stt.md (~2,850 tokens)
- Slim: https://www.anchorterminal.com/compare/openai-speech-to-text-vs-speechmatics-stt.min.md (~780 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/openai-speech-to-text-vs-speechmatics-stt.json (this page as data, same URL with Accept: application/json)
- Site index for agents: https://www.anchorterminal.com/llms.txt (full text: https://www.anchorterminal.com/llms-full.txt)
- API: https://www.anchorterminal.com/api/v1/index.json
- Updated: 2026-10-09

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.

- OpenAI Speech to Text: grade BB, 72.4/100, rank #106 of 950. Markdown https://www.anchorterminal.com/tools/openai-speech-to-text.md · JSON https://www.anchorterminal.com/api/v1/tools/openai-speech-to-text.json
- Speechmatics Speech-to-Text: grade B, 67.1/100, rank #262 of 950. Markdown https://www.anchorterminal.com/tools/speechmatics-stt.md · JSON https://www.anchorterminal.com/api/v1/tools/speechmatics-stt.json
- Best speech-to-text APIs for AI agents: https://www.anchorterminal.com/best/speech-to-text/index.md
- All 91 stt comparisons: https://www.anchorterminal.com/compare/speech-to-text/index.md

## Which one, for what

### 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 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

### Speechmatics Speech-to-Text (B)

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 | OpenAI Speech to Text | Speechmatics Speech-to-Text | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 80 | 70 | OpenAI Speech to Text +10 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 88 | 65 | OpenAI Speech to Text +23 |
| Agent ergonomics | 13% (16.2 this run) | 78 | 80 | Speechmatics Speech-to-Text +2 |
| Security & auth | 14% (17.5 this run) | 86 | 65 | OpenAI Speech to Text +21 |
| Payments & pricing | 10% (12.5 this run) | 20 | 40 | Speechmatics Speech-to-Text +20 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 75 | 75 | even |
| Transparency & trust | 7% (8.8 this run) | 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

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.

### Speechmatics Speech-to-Text

1. Set `"model": "enhanced"` explicitly. The default is `standard`
2. Use notifications instead of polling. Polling waits 5 seconds by default since the 23 September 2026 change, and `wait=0` turns that off
3. Fetch batch transcripts within 7 days. After that the API returns 404 `expired`
4. Pass a `fetch_data` URL for files over 1 GB
5. Use `/v2/agent` with `linden-1` for 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.


## For agents

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

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