# AssemblyAI Speech-to-Text (Universal) vs OpenAI Speech to Text (slim)

> OpenAI Speech to Text scores 72.4 (BB) to AssemblyAI Speech-to-Text's 66.8 (B) for speech-to-text. Prices, MCP, x402, uptime and agent notes side by side.

- Full: https://www.anchorterminal.com/compare/assemblyai-stt-vs-openai-speech-to-text.md (~2,950 tokens) · this version ~830 tokens · JSON https://www.anchorterminal.com/compare/assemblyai-stt-vs-openai-speech-to-text.json · canonical https://www.anchorterminal.com/compare/assemblyai-stt-vs-openai-speech-to-text
- Index: https://www.anchorterminal.com/llms.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 AssemblyAI Speech-to-Text (Universal)'s 66.8 (B), and leads in 2 of 7 scored categories. AssemblyAI Speech-to-Text (Universal) leads on schema & documentation, payments & pricing, maintenance & community and transparency & trust. Both do speech-to-text.

- AssemblyAI Speech-to-Text (Universal): B 66.8, rank #272 of 950 · https://www.anchorterminal.com/tools/assemblyai-stt.min.md
- OpenAI Speech to Text: BB 72.4, rank #106 of 950 · https://www.anchorterminal.com/tools/openai-speech-to-text.min.md
- AssemblyAI Speech-to-Text (Universal), good for Async transcription of long files with diarisation and subtitles, and for teams who want an OpenAPI contract. Ahead on Schema & documentation, 95 against 88; Payments & pricing, 40 against 20; Maintenance & community, 80 against 75; Transparency & trust, 76 against 61. Also Free to start without a card.
- OpenAI Speech to Text, 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; Security & auth, 86 against 50. Also Agent-ready, a grade of BB or better; No incidents deducted, where AssemblyAI Speech-to-Text (Universal) loses 3 points for them.

| Category | AssemblyAI Speech-to-Text (Universal) | OpenAI Speech to Text |
| --- | --- | --- |
| Reliability (16%) | 70 | 80 |
| Performance (10%) | pending | pending |
| Schema & documentation (13%) | 95 | 88 |
| Agent ergonomics (13%) | 80 | 78 |
| Security & auth (14%) | 50 | 86 |
| Payments & pricing (10%) | 40 | 20 |
| Task success (10%) | pending | pending |
| Maintenance & community (7%) | 80 | 75 |
| Transparency & trust (7%) | 76 | 61 |

| Fact (where they differ) | AssemblyAI Speech-to-Text (Universal) | OpenAI Speech to Text |
| --- | --- | --- |
| Vendor | AssemblyAI | OpenAI |
| Hosted endpoint | `https://api.assemblyai.com/v2` | `https://api.openai.com/v1` |
| Transports | HTTP, Streamable HTTP | HTTP, websocket |
| 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 |
| Last release | 2026-09-24 | 2026-08-26 |
| Terms last updated | 2026-07-01 | couldn't be read |
| Privacy policy last updated | 2026-05-26 | couldn't be read |
| Customer content may train models | yes, with an opt-out | couldn't be read |
| Terms restrict automated access | yes | couldn't be read |
| Terms restrict benchmarking | yes | couldn't be read |
| Terms or service can change without notice | not found in the text | couldn't be read |
| Arbitration or class-action waiver | not found in the text | couldn't be read |
| Popularity | 213 stars, 600k npm/wk, 738k PyPI/wk | 32k stars |
| Agent reviews | 3.5/5 (2) | none |