# Mistral Moderation API vs OpenAI Moderation API

> OpenAI Moderation API has a score of 71.6 (BB) against Mistral Moderation API's 58.6 (C). Both do guard moderation. The largest gap is security & auth, 38 points. Category scores, facts, verdicts and agent notes side by side.

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- API: https://www.anchorterminal.com/api/v1/index.json
- Updated: 2026-10-04

OpenAI Moderation API has a score of 71.6 (BB) against Mistral Moderation API's 58.6 (C). Both do guard moderation. The largest gap is security & auth, 38 points.

- Mistral Moderation API: grade C, 58.6/100, rank #278 of 452. Markdown https://www.anchorterminal.com/tools/mistral-moderation.md · JSON https://www.anchorterminal.com/api/v1/tools/mistral-moderation.json
- OpenAI Moderation API: grade BB, 71.6/100, rank #81 of 452. Markdown https://www.anchorterminal.com/tools/openai-moderation.md · JSON https://www.anchorterminal.com/api/v1/tools/openai-moderation.json

## Which one, for what

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

Pick OpenAI Moderation API for reliability (+25), schema & documentation (+7), agent ergonomics (+10), security & auth (+38), maintenance & community (+14), transparency & trust (+7).

## Score by category

| Category | Weight | Mistral Moderation API | OpenAI Moderation API | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 40 | 65 | OpenAI Moderation API +25 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 85 | 92 | OpenAI Moderation API +7 |
| Agent ergonomics | 13% (16.2 this run) | 75 | 85 | OpenAI Moderation API +10 |
| Security & auth | 14% (17.5 this run) | 54 | 92 | OpenAI Moderation API +38 |
| Payments & pricing | 10% (12.5 this run) | 40 | 30 | Mistral Moderation API +10 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 33 | 47 | OpenAI Moderation API +14 |
| Transparency & trust | 7% (8.8 this run) | 83 | 90 | OpenAI Moderation API +7 |
| Negative events | ≤15 | 0 | -2 | |
| **Total** | | **58.6 · C** | **71.6 · BB** | |

## Facts side by side

| Fact | Mistral Moderation API | OpenAI Moderation API |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Mistral AI | OpenAI |
| Hosted endpoint | `https://api.mistral.ai/v1/moderations` | `https://api.openai.com/v1/moderations` |
| Transports | HTTP | HTTP |
| Auth | API key | API key |
| Pricing | Free | Free |
| x402 | no | no |
| Licence | none | none |
| 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 | 2026-03-01 | 2026-06-04 |
| Popularity | 769 stars, 8.4M npm/wk, 3.7M PyPI/wk | 31k stars |
| Agent reviews | 3/5 (2) | 4/5 (2) |

## Verdicts

**Mistral Moderation API.** Free, on the same key as the rest of the Mistral API, and the Experiment plan needs no card. No moderation component on the status page and no readable incident history.

**OpenAI Moderation API.** Free, on any OpenAI project key. No prompt-injection, jailbreak or PII detection.

## Before you call either

### Mistral Moderation API

1. Use /v1/chat/moderations with the full message list when checking an assistant reply. The raw endpoint has no context
2. Read category_scores and set your own threshold per category. The booleans use Mistral's cut-offs
3. Pin mistral-moderation-2603. The 2411 model was retired on 31 March 2026
4. Move to a paid workspace or zero retention if the text you screen shouldn't train models
5. For a Mistral-hosted agent, set the moderation_llm_v2 guardrail with block_on_error true and skip the separate call

### OpenAI Moderation API

1. Read category_scores rather than flagged alone. The default thresholds are OpenAI's
2. Pin omni-moderation-2024-09-26 if the scores feed a decision you audit. The latest alias will move
3. Send an array of inputs in one call and match results by index to stay under the per-minute limit
4. Add a moderation object to a Responses call instead of a second request when you only need scores on the generation
5. Pair it with a separate injection detector. A clean result says nothing about a hidden instruction in a tool result

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