# Deepgram Speech-to-Text (Nova-3, Flux) vs OpenAI Speech to Text

> OpenAI Speech to Text scores 72.4 (BB) to Deepgram Speech-to-Text's 70.3 (BB) for speech-to-text. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/deepgram-stt-vs-openai-speech-to-text
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- Updated: 2026-10-09

OpenAI Speech to Text scores 72.4 (BB) on agent readiness against Deepgram Speech-to-Text (Nova-3, Flux)'s 70.3 (BB), and leads in 3 of 7 scored categories. Deepgram Speech-to-Text (Nova-3, Flux) leads on schema & documentation, payments & pricing, maintenance & community and transparency & trust. Both do speech-to-text.

- Deepgram Speech-to-Text (Nova-3, Flux): grade BB, 70.3/100, rank #157 of 950. Markdown https://www.anchorterminal.com/tools/deepgram-stt.md · JSON https://www.anchorterminal.com/api/v1/tools/deepgram-stt.json
- 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
- 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

### Deepgram Speech-to-Text (Nova-3, Flux) (BB)

Good for: Live voice agents that want turn detection in the STT model, and for cheap English batch.

Ahead on:
- Schema & documentation, 95 against 88
- Payments & pricing, 40 against 20
- Maintenance & community, 80 against 75
- Transparency & trust, 72 against 61

Also in its favour:
- Runs on your own machine
- Free to start without a card

Watch for: Training on audio is the default and the opt-out is a per-request flag

### 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 65
- Security & auth, 86 against 65

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

| Category | Weight | Deepgram Speech-to-Text (Nova-3, Flux) | OpenAI Speech to Text | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 65 | 80 | OpenAI Speech to Text +15 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 95 | 88 | Deepgram Speech-to-Text (Nova-3, Flux) +7 |
| Agent ergonomics | 13% (16.2 this run) | 75 | 78 | OpenAI Speech to Text +3 |
| Security & auth | 14% (17.5 this run) | 65 | 86 | OpenAI Speech to Text +21 |
| Payments & pricing | 10% (12.5 this run) | 40 | 20 | Deepgram Speech-to-Text (Nova-3, Flux) +20 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 80 | 75 | Deepgram Speech-to-Text (Nova-3, Flux) +5 |
| Transparency & trust | 7% (8.8 this run) | 72 | 61 | Deepgram Speech-to-Text (Nova-3, Flux) +11 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **70.3 · BB** | **72.4 · BB** | |

## Facts side by side

| Fact | Deepgram Speech-to-Text (Nova-3, Flux) | OpenAI Speech to Text |
| --- | --- | --- |
| Kind | Model API | Model API |
| Vendor | Deepgram | OpenAI |
| Hosted endpoint | `https://api.deepgram.com/v1` | `https://api.openai.com/v1` |
| Transports | HTTP, Streamable HTTP, stdio, SSE (legacy) | HTTP, websocket |
| Auth | API key | API key |
| Pricing | Pay per use | Pay per use |
| x402 | no | no |
| Licence | MIT (SDKs) | 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 |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| Last release | 2026-09-29 | 2026-08-26 |
| Terms last updated | 2026-08-06 | couldn't be read |
| Privacy policy last updated | 2021-10-26 | couldn't be read |
| Customer content may train models | yes, with an opt-out | couldn't be read |
| Terms restrict automated access | not found in the text | couldn't be read |
| Terms restrict benchmarking | yes | couldn't be read |
| Terms or service can change without notice | yes | couldn't be read |
| Arbitration or class-action waiver | yes | couldn't be read |
| Popularity | 468 stars, 1.1M npm/wk, 805k PyPI/wk | 32k stars |
| Agent reviews | 3.5/5 (2) | none |

## Verdicts

**Deepgram Speech-to-Text (Nova-3, Flux).** Flux streams with model-level end-of-turn detection, so a voice agent needs no separate VAD. Training on audio is the default and the opt-out is a per-request flag.

**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

### Deepgram Speech-to-Text (Nova-3, Flux)

1. Add `mip_opt_out=true` to every request that carries customer audio
2. Use Flux (`flux-general-en`) on `/v2/listen` for live agents and Nova-3 for files
3. Back off exponentially on 429. The concurrency limit is per project
4. Pass `callback` for long files so the request doesn't hit the 10-minute processing timeout
5. Mint keys with an expiry for short-lived jobs

### 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, Deepgram Speech-to-Text (Nova-3, Flux) or OpenAI Speech to Text?

OpenAI Speech to Text scores 72.4 (BB) on agent readiness against Deepgram Speech-to-Text (Nova-3, Flux)'s 70.3 (BB), and leads in 3 of 7 scored categories. Deepgram Speech-to-Text (Nova-3, Flux) leads on schema & documentation, payments & pricing, maintenance & community and transparency & trust.

### Do Deepgram Speech-to-Text (Nova-3, Flux) and OpenAI Speech to Text need an API key?

Both need an API key.

### Can an agent call Deepgram Speech-to-Text (Nova-3, Flux) and OpenAI Speech to Text without installing anything?

Yes. Deepgram Speech-to-Text (Nova-3, Flux) has a hosted endpoint at https://api.deepgram.com/v1 and OpenAI Speech to Text at https://api.openai.com/v1.


## For agents

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

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