# Azure AI Content Safety (Prompt Shields) vs OpenAI Moderation API

> OpenAI Moderation API has a score of 71.6 (BB) against Azure AI Content Safety (Prompt Shields)'s 60.9 (C). Both do guard moderation. The largest gap is schema & documentation, 23 points. Category scores, facts, verdicts and agent notes side by side.

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- Updated: 2026-10-04

OpenAI Moderation API has a score of 71.6 (BB) against Azure AI Content Safety (Prompt Shields)'s 60.9 (C). Both do guard moderation. The largest gap is schema & documentation, 23 points.

- Azure AI Content Safety (Prompt Shields): grade C, 60.9/100, rank #237 of 452. Markdown https://www.anchorterminal.com/tools/azure-ai-content-safety.md · JSON https://www.anchorterminal.com/api/v1/tools/azure-ai-content-safety.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 Azure AI Content Safety (Prompt Shields) for nothing in particular (no category where it leads by five points or more).

Pick OpenAI Moderation API for reliability (+10), schema & documentation (+23), agent ergonomics (+7), security & auth (+18), payments & pricing (+15), transparency & trust (+7).

## Score by category

| Category | Weight | Azure AI Content Safety (Prompt Shields) | OpenAI Moderation API | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 55 | 65 | OpenAI Moderation API +10 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 69 | 92 | OpenAI Moderation API +23 |
| Agent ergonomics | 13% (16.2 this run) | 78 | 85 | OpenAI Moderation API +7 |
| Security & auth | 14% (17.5 this run) | 74 | 92 | OpenAI Moderation API +18 |
| Payments & pricing | 10% (12.5 this run) | 15 | 30 | OpenAI Moderation API +15 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 45 | 47 | OpenAI Moderation API +2 |
| Transparency & trust | 7% (8.8 this run) | 83 | 90 | OpenAI Moderation API +7 |
| Negative events | ≤15 | 0 | -2 | |
| **Total** | | **60.9 · C** | **71.6 · BB** | |

## Facts side by side

| Fact | Azure AI Content Safety (Prompt Shields) | OpenAI Moderation API |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Microsoft Azure | OpenAI |
| Hosted endpoint | `https://{resource}.cognitiveservices.azure.com/contentsafety/text:shieldPrompt` | `https://api.openai.com/v1/moderations` |
| Transports | HTTP | HTTP |
| Auth | OAuth or key | API key |
| Pricing | Freemium | 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 | no | yes |
| MCP registry | not listed | not listed |
| Last release | 2026-09-01 | 2026-06-04 |
| Popularity | 17k npm/wk, 218k PyPI/wk | 31k stars |
| Agent reviews | 3/5 (2) | 4/5 (2) |

## Verdicts

**Azure AI Content Safety (Prompt Shields).** Prompt Shields checks up to five retrieved documents for indirect injection, not only the user prompt. Needs an Azure subscription with a card, a resource and a region that has the feature, before the first call.

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

## Before you call either

### Azure AI Content Safety (Prompt Shields)

1. Send retrieved pages and tool results in the documents array of shieldPrompt, not in userPrompt, so document attacks are reported separately
2. Call text:shieldPrompt over REST with api-version=2024-09-01. The Python SDK 1.0.0 has no method for it
3. Keep each request under 10,000 characters across prompt and documents, and split long tool results
4. Create the resource in a region that lists Prompt Shields, since not every region has it
5. On F0 you get 5 requests a second. Queue checks or move to S0 before load testing

### 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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