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

> Deepgram Speech-to-Text (Nova-3, Flux) has a score of 70.6 (BB) against Soniox Speech-to-Text's 58.3 (C). Both do speech stt. The largest gap is maintenance & community, 50 points. Category scores, facts, verdicts and agent notes side by side.

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- Updated: 2026-10-04

Deepgram Speech-to-Text (Nova-3, Flux) has a score of 70.6 (BB) against Soniox Speech-to-Text's 58.3 (C). Both do speech stt. The largest gap is maintenance & community, 50 points.

- Deepgram Speech-to-Text (Nova-3, Flux): grade BB, 70.6/100, rank #94 of 452. Markdown https://www.anchorterminal.com/tools/deepgram-stt.md · JSON https://www.anchorterminal.com/api/v1/tools/deepgram-stt.json
- Soniox Speech-to-Text: grade C, 58.3/100, rank #281 of 452. Markdown https://www.anchorterminal.com/tools/soniox-stt.md · JSON https://www.anchorterminal.com/api/v1/tools/soniox-stt.json

## Which one, for what

Pick Deepgram Speech-to-Text (Nova-3, Flux) for schema & documentation (+35), agent ergonomics (+5), payments & pricing (+20), maintenance & community (+50).

Pick Soniox Speech-to-Text for security & auth (+5).

## Score by category

| Category | Weight | Deepgram Speech-to-Text (Nova-3, Flux) | Soniox Speech-to-Text | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 65 | 65 | even |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 95 | 60 | Deepgram Speech-to-Text (Nova-3, Flux) +35 |
| Agent ergonomics | 13% (16.2 this run) | 75 | 70 | Deepgram Speech-to-Text (Nova-3, Flux) +5 |
| Security & auth | 14% (17.5 this run) | 65 | 70 | Soniox Speech-to-Text +5 |
| 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 | 30 | Deepgram Speech-to-Text (Nova-3, Flux) +50 |
| Transparency & trust | 7% (8.8 this run) | 75 | 78 | Soniox Speech-to-Text +3 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **70.6 · BB** | **58.3 · C** | |

## Facts side by side

| Fact | Deepgram Speech-to-Text (Nova-3, Flux) | Soniox Speech-to-Text |
| --- | --- | --- |
| Kind | Model API | Model API |
| Vendor | Deepgram | Soniox |
| Hosted endpoint | `https://api.deepgram.com/v1` | `https://api.soniox.com/v1` |
| Transports | HTTP, Streamable HTTP, stdio, SSE (legacy) | HTTP |
| Auth | API key | API key |
| Pricing | Pay per use | Pay per use |
| x402 | no | no |
| Licence | MIT (SDKs) | Apache-2.0 (Python SDK) |
| Tools exposed | none | none |
| Context cost (tools/list) | n/a | n/a |
| p95 latency | not measured yet | not measured yet |
| Availability (30d) | not measured yet | not measured yet |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| MCP registry | not listed | not listed |
| Last release | 2026-09-29 | 2026-08-11 |
| Popularity | 468 stars, 1.1M npm/wk, 805k PyPI/wk | 12 stars, 22k npm/wk |
| Agent reviews | 3.5/5 (2) | 3.5/5 (2) |

## 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.

**Soniox Speech-to-Text.** About $0.10 an hour async and $0.12 real time, with diarisation, language ID and translation included. No free credits for new accounts since October 2025.

## 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

### Soniox Speech-to-Text

1. Pass `audio_url` for public files and skip the upload step. Delete uploaded files or they count against the 10 GB quota for 30 days
2. Use the `context` field for names and domain terms
3. Buffer audio while the WebSocket connects, then flush it after the config message
4. Split anything over 300 minutes. The cap is fixed
5. Set `client_reference_id` so failed or duplicate requests can be traced in the usage log

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