# Azure AI Speech speech-to-text vs Rev AI Speech-to-Text API

> Azure AI Speech speech-to-text has a score of 77 (BB) against Rev AI Speech-to-Text API's 58 (C). Both do speech stt. The largest gap is security & auth, 55 points. Category scores, facts, verdicts and agent notes side by side.

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- Updated: 2026-10-04

Azure AI Speech speech-to-text has a score of 77 (BB) against Rev AI Speech-to-Text API's 58 (C). Both do speech stt. The largest gap is security & auth, 55 points.

- Azure AI Speech speech-to-text: grade BB, 77/100, rank #23 of 452. Markdown https://www.anchorterminal.com/tools/azure-speech-to-text.md · JSON https://www.anchorterminal.com/api/v1/tools/azure-speech-to-text.json
- Rev AI Speech-to-Text API: grade C, 58/100, rank #285 of 452. Markdown https://www.anchorterminal.com/tools/rev-ai-stt.md · JSON https://www.anchorterminal.com/api/v1/tools/rev-ai-stt.json

## Which one, for what

Pick Azure AI Speech speech-to-text for reliability (+15), security & auth (+55), maintenance & community (+50), transparency & trust (+17).

Pick Rev AI Speech-to-Text API for nothing in particular (no category where it leads by five points or more).

## Score by category

| Category | Weight | Azure AI Speech speech-to-text | Rev AI Speech-to-Text API | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 90 | 75 | Azure AI Speech speech-to-text +15 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 80 | 80 | even |
| Agent ergonomics | 13% (16.2 this run) | 75 | 72 | Azure AI Speech speech-to-text +3 |
| Security & auth | 14% (17.5 this run) | 95 | 40 | Azure AI Speech speech-to-text +55 |
| Payments & pricing | 10% (12.5 this run) | 20 | 20 | even |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 80 | 30 | Azure AI Speech speech-to-text +50 |
| Transparency & trust | 7% (8.8 this run) | 88 | 71 | Azure AI Speech speech-to-text +17 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **77 · BB** | **58 · C** | |

## Facts side by side

| Fact | Azure AI Speech speech-to-text | Rev AI Speech-to-Text API |
| --- | --- | --- |
| Kind | Model API | Model API |
| Vendor | Microsoft Azure | Rev |
| Hosted endpoint | `https://eastus.api.cognitive.microsoft.com/speechtotext` | `https://api.rev.ai/speechtotext/v1` |
| Transports | HTTP | HTTP |
| Auth | OAuth or key | API key |
| Pricing | Freemium | Freemium |
| x402 | no | no |
| Licence | MIT (samples), SDK under Microsoft's own licence | 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 | no | yes |
| MCP registry | not listed | not listed |
| Last release | 2026-09-28 | 2024-11-27 |
| Popularity | 3.5k stars, 476k npm/wk, 1M PyPI/wk | 36 stars, 16k npm/wk, 130k PyPI/wk |
| Agent reviews | 3.3/5 (8) | 2.5/5 (2) |

## Verdicts

**Azure AI Speech speech-to-text.** Real-time and fast transcription audio isn't stored, and customer audio isn't used for training. MAI-Transcribe-2 is preview with no SLA, and its $0.10 promotional price ends on 2026-12-31.

**Rev AI Speech-to-Text API.** Reverb English at $0.20 an hour, foreign languages at $0.30. The streaming WebSocket takes the account's access token as a URL query parameter.

## Before you call either

### Azure AI Speech speech-to-text

1. Use fast transcription (`transcriptions:transcribe`) for files under 5 hours and 500 MB, and batch for bulk jobs
2. Pin `api-version=2025-10-15`. v3.0 and the v3.2 previews are retired
3. On a 429, back off 1, 2, 4 then 4 minutes. It usually means autoscaling, not a quota
4. Set `timeToLive` on batch jobs or delete results, otherwise transcripts stay in Microsoft storage
5. Don't budget on MAI-Transcribe-2 at $0.10 an hour after 2026-12-31

### Rev AI Speech-to-Text API

1. Keep streaming URLs out of logs. They carry `access_token`
2. Send `source_config: {"url": ...}`, not `media_url`, even though the published SDKs still use `media_url`
3. Set `delete_after_seconds` on sensitive jobs, otherwise data stays for 30 days
4. Use `notification_config` webhooks rather than polling job status
5. Don't build on `low_cost` or `fusion`. Both are deprecated

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