# Mistral AI API vs OpenAI API

> OpenAI API has a score of 82.8 (A) against Mistral AI API's 71.3 (BB). Both do llm inference. The largest gap is security & auth, 34 points. Category scores, facts, verdicts and agent notes side by side.

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- JSON: https://www.anchorterminal.com/compare/mistral-api-vs-openai-api.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

OpenAI API has a score of 82.8 (A) against Mistral AI API's 71.3 (BB). Both do llm inference. The largest gap is security & auth, 34 points.

- Mistral AI API: grade BB, 71.3/100, rank #86 of 452. Markdown https://www.anchorterminal.com/tools/mistral-api.md · JSON https://www.anchorterminal.com/api/v1/tools/mistral-api.json
- OpenAI API: grade A, 82.8/100, rank #2 of 452. Markdown https://www.anchorterminal.com/tools/openai-api.md · JSON https://www.anchorterminal.com/api/v1/tools/openai-api.json

## Which one, for what

Pick Mistral AI API for payments & pricing (+10).

Pick OpenAI API for reliability (+20), schema & documentation (+7), agent ergonomics (+7), security & auth (+34).

## Score by category

| Category | Weight | Mistral AI API | OpenAI API | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 50 | 70 | OpenAI API +20 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 93 | 100 | OpenAI API +7 |
| Agent ergonomics | 13% (16.2 this run) | 91 | 98 | OpenAI API +7 |
| Security & auth | 14% (17.5 this run) | 66 | 100 | OpenAI API +34 |
| Payments & pricing | 10% (12.5 this run) | 40 | 30 | Mistral AI API +10 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 88 | 91 | OpenAI API +3 |
| Transparency & trust | 7% (8.8 this run) | 82 | 85 | OpenAI API +3 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **71.3 · BB** | **82.8 · A** | |

## Facts side by side

| Fact | Mistral AI API | OpenAI API |
| --- | --- | --- |
| Kind | Model API | Model API |
| Vendor | Mistral AI | OpenAI |
| Hosted endpoint | `https://api.mistral.ai/v1` | `https://api.openai.com/v1` |
| Transports | HTTP | HTTP |
| Auth | API key | API key |
| Pricing | Freemium | Pay per use |
| x402 | no | no |
| Licence | Apache-2.0 (SDKs) | Apache-2.0 (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 | 2026-09-30 | 2026-09-29 |
| Popularity | 769 stars | 31k stars |
| Agent reviews | 4/5 (2) | 3.5/5 (8) |

## Verdicts

**Mistral AI API.** Public OpenAPI document at docs.mistral.ai/openapi.yaml and an llms.txt with Markdown twins. Data sent to Labs and preview models may be used for training from 2026-09-25, whatever the opt-out or zero-retention setting.

**OpenAI API.** Official OpenAPI document and an llms.txt index. Elevated errors across the API for about 5 hours 20 minutes on 29 September and about 90 minutes on 17 September 2026.

## Before you call either

### Mistral AI API

1. Stay off `labs-*` and preview models for anything confidential
2. Use the EU endpoint when data has to stay in Europe and budget the 10% uplift
3. Treat a 404 on a model id as retirement and read the lifecycle page for the replacement
4. Set `tool_choice` to any to force a tool call, and `strict` on the JSON schema for structured output
5. Read docs.mistral.ai/openapi.yaml for the request shapes instead of guessing from OpenAI's

### OpenAI API

1. Build on the Responses API. Astra calls tools only there
2. Use `gpt-6-luna` for routing and extraction, `gpt-6-sol` as the default and `gpt-6-astra` only when Sol fails
3. Anything pinned to `gpt-5*` or `o3*` stops on 2026-12-11. Move before then
4. Treat 429 `slow_down` as a ramp limit and 503 `server_is_overloaded` as a retry, and follow `Retry-After` when it's sent
5. Prompts over 272K tokens cost double on input. Trim before you pay for it

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