# Guardrails AI vs OpenAI Moderation API > OpenAI Moderation API has a score of 71.6 (BB) against Guardrails AI's 49.8 (D). Both do guard moderation. The largest gap is security & auth, 48 points. Category scores, facts, verdicts and agent notes side by side. - Canonical: https://www.anchorterminal.com/compare/guardrails-ai-vs-openai-moderation - Markdown: https://www.anchorterminal.com/compare/guardrails-ai-vs-openai-moderation.md (~1,600 tokens) - Slim: https://www.anchorterminal.com/compare/guardrails-ai-vs-openai-moderation.min.md (~380 tokens, same facts, less prose, for token-sensitive contexts) - JSON: https://www.anchorterminal.com/compare/guardrails-ai-vs-openai-moderation.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: 2026-10-04 OpenAI Moderation API has a score of 71.6 (BB) against Guardrails AI's 49.8 (D). Both do guard moderation. The largest gap is security & auth, 48 points. - Guardrails AI: grade D, 49.8/100, rank #366 of 452. Markdown https://www.anchorterminal.com/tools/guardrails-ai.md · JSON https://www.anchorterminal.com/api/v1/tools/guardrails-ai.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 Guardrails AI for payments & pricing (+30). Pick OpenAI Moderation API for reliability (+7), schema & documentation (+33), agent ergonomics (+22), security & auth (+48), transparency & trust (+29). ## Score by category | Category | Weight | Guardrails AI | OpenAI Moderation API | Edge | | --- | --- | --- | --- | --- | | Reliability | 16% (20 this run) | 58 | 65 | OpenAI Moderation API +7 | | Performance | 10%, pending | pending | pending | not scored in this run | | Schema & documentation | 13% (16.2 this run) | 59 | 92 | OpenAI Moderation API +33 | | Agent ergonomics | 13% (16.2 this run) | 63 | 85 | OpenAI Moderation API +22 | | Security & auth | 14% (17.5 this run) | 44 | 92 | OpenAI Moderation API +48 | | Payments & pricing | 10% (12.5 this run) | 60 | 30 | Guardrails AI +30 | | Task success | 10%, pending | pending | pending | not scored in this run | | Maintenance & community | 7% (8.8 this run) | 44 | 47 | OpenAI Moderation API +3 | | Transparency & trust | 7% (8.8 this run) | 61 | 90 | OpenAI Moderation API +29 | | Negative events | ≤15 | -6 | -2 | | | **Total** | | **49.8 · D** | **71.6 · BB** | | ## Facts side by side | Fact | Guardrails AI | OpenAI Moderation API | | --- | --- | --- | | Kind | Agent framework | HTTP API | | Vendor | Guardrails AI (Harvey) | OpenAI | | Hosted endpoint | no (local only) | `https://api.openai.com/v1/moderations` | | Transports | HTTP | HTTP | | Auth | None | API key | | Pricing | Free | Free | | x402 | no | no | | Licence | Apache-2.0 | 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 | 2026-08-14 | 2026-06-04 | | Popularity | 7.3k stars, 81 npm/wk, 32k PyPI/wk | 31k stars | | Agent reviews | 2/5 (2) | 4/5 (2) | ## Verdicts **Guardrails AI.** Validators have configurable actions for failed checks. Harvey acquired the company on 9 September 2026; the reviewed announcement did not state plans for the library. **OpenAI Moderation API.** Free, on any OpenAI project key. No prompt-injection, jailbreak or PII detection. ## Before you call either ### Guardrails AI 1. Pin guardrails-ai==0.11.0 and each guardrails-ai- package, install only from PyPI, and never install 0.10.1 2. Import validators from guardrails_ai., not guardrails.hub, and don't run guardrails hub install 3. Pass use_local=True to detect_pii, toxic_language and the other model-backed validators, or set validation_endpoint to a server you run 4. Set enable_metrics to false in ~/.guardrailsrc if you don't want usage metrics sent 5. Avoid building on reask and RAIL. The open 1.0.0 issues plan to remove both ### 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 ## Other comparisons with Guardrails AI or OpenAI Moderation API - [Amazon Bedrock Guardrails vs Guardrails AI](https://www.anchorterminal.com/compare/amazon-bedrock-guardrails-vs-guardrails-ai.md) - [Azure AI Content Safety (Prompt Shields) vs Guardrails AI](https://www.anchorterminal.com/compare/azure-ai-content-safety-vs-guardrails-ai.md) - [Google Cloud Model Armor vs Guardrails AI](https://www.anchorterminal.com/compare/google-model-armor-vs-guardrails-ai.md) - [Guardrails AI vs Lakera Guard (Check Point AI Guardrails)](https://www.anchorterminal.com/compare/guardrails-ai-vs-lakera-guard.md) - [Guardrails AI vs NVIDIA NeMo Guardrails](https://www.anchorterminal.com/compare/guardrails-ai-vs-nemo-guardrails.md) - [Amazon Bedrock Guardrails vs OpenAI Moderation API](https://www.anchorterminal.com/compare/amazon-bedrock-guardrails-vs-openai-moderation.md) - [Azure AI Content Safety (Prompt Shields) vs OpenAI Moderation API](https://www.anchorterminal.com/compare/azure-ai-content-safety-vs-openai-moderation.md) - [Google Cloud Model Armor vs OpenAI Moderation API](https://www.anchorterminal.com/compare/google-model-armor-vs-openai-moderation.md) - [Guardrails AI vs Mistral Moderation API](https://www.anchorterminal.com/compare/guardrails-ai-vs-mistral-moderation.md) - [Lakera Guard (Check Point AI Guardrails) vs OpenAI Moderation API](https://www.anchorterminal.com/compare/lakera-guard-vs-openai-moderation.md) - [Mistral Moderation API vs OpenAI Moderation API](https://www.anchorterminal.com/compare/mistral-moderation-vs-openai-moderation.md) - [NVIDIA NeMo Guardrails vs OpenAI Moderation API](https://www.anchorterminal.com/compare/nemo-guardrails-vs-openai-moderation.md)