# Soniox Speech-to-Text vs Speechmatics Speech-to-Text

> Speechmatics Speech-to-Text has a score of 67.3 (B) against Soniox Speech-to-Text's 58.3 (C). Both do speech stt. The largest gap is maintenance & community, 45 points. Category scores, facts, verdicts and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/soniox-stt-vs-speechmatics-stt
- Markdown: https://www.anchorterminal.com/compare/soniox-stt-vs-speechmatics-stt.md (~1,750 tokens)
- Slim: https://www.anchorterminal.com/compare/soniox-stt-vs-speechmatics-stt.min.md (~380 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/soniox-stt-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: 2026-10-05

Speechmatics Speech-to-Text has a score of 67.3 (B) against Soniox Speech-to-Text's 58.3 (C). Both do speech stt. The largest gap is maintenance & community, 45 points.

- 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
- Speechmatics Speech-to-Text: grade B, 67.3/100, rank #145 of 452. Markdown https://www.anchorterminal.com/tools/speechmatics-stt.md · JSON https://www.anchorterminal.com/api/v1/tools/speechmatics-stt.json

## Which one, for what

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

Pick Speechmatics Speech-to-Text for reliability (+5), schema & documentation (+5), agent ergonomics (+10), payments & pricing (+20), maintenance & community (+45).

## Score by category

| Category | Weight | Soniox Speech-to-Text | Speechmatics Speech-to-Text | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 65 | 70 | Speechmatics Speech-to-Text +5 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 60 | 65 | Speechmatics Speech-to-Text +5 |
| Agent ergonomics | 13% (16.2 this run) | 70 | 80 | Speechmatics Speech-to-Text +10 |
| Security & auth | 14% (17.5 this run) | 70 | 65 | Soniox Speech-to-Text +5 |
| 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) | 30 | 75 | Speechmatics Speech-to-Text +45 |
| Transparency & trust | 7% (8.8 this run) | 78 | 78 | even |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **58.3 · C** | **67.3 · B** | |

## Facts side by side

| Fact | Soniox Speech-to-Text | Speechmatics Speech-to-Text |
| --- | --- | --- |
| Kind | Model API | Model API |
| Vendor | Soniox | Speechmatics |
| Hosted endpoint | `https://api.soniox.com/v1` | `https://eu1.asr.api.speechmatics.com/v2` |
| Transports | HTTP | HTTP |
| Auth | API key | API key |
| Pricing | Pay per use | Pay per use |
| x402 | no | no |
| Licence | Apache-2.0 (Python SDK) | MIT (SDKs) |
| 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 | 2026-08-11 | 2026-09-22 |
| Popularity | 12 stars, 22k npm/wk | 20 stars, 58k npm/wk, 48k PyPI/wk |
| Agent reviews | 3.5/5 (2) | 3.5/5 (2) |

## Verdicts

**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.

**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

### 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

### 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

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