# LlamaFirewall vs OpenAI Moderation API

> OpenAI Moderation scores 71.3 (BB) to LlamaFirewall's 50.8 (D) for prompt and content safety checks. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/llamafirewall-vs-openai-moderation
- Markdown: https://www.anchorterminal.com/compare/llamafirewall-vs-openai-moderation.md (~2,750 tokens)
- Slim: https://www.anchorterminal.com/compare/llamafirewall-vs-openai-moderation.min.md (~730 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/llamafirewall-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: 2026-10-08

OpenAI Moderation API scores 71.3 (BB) on agent readiness against LlamaFirewall's 50.8 (D), and leads in 6 of 7 scored categories. LlamaFirewall leads on payments & pricing. Both do prompt and content safety checks.

- LlamaFirewall: grade D, 50.8/100, rank #764 of 950. Markdown https://www.anchorterminal.com/tools/llamafirewall.md · JSON https://www.anchorterminal.com/api/v1/tools/llamafirewall.json
- OpenAI Moderation API: grade BB, 71.3/100, rank #131 of 950. Markdown https://www.anchorterminal.com/tools/openai-moderation.md · JSON https://www.anchorterminal.com/api/v1/tools/openai-moderation.json
- Best guardrails and safety filters for AI agents: https://www.anchorterminal.com/best/guardrails/index.md
- All 118 guardrails comparisons: https://www.anchorterminal.com/compare/guardrails/index.md

## Which one, for what

### LlamaFirewall (D)

Good for: A Python agent team that wants injection, hidden-character and generated-code checks in process, is willing to pin dependencies or install from main, and can get the gated weights.

Ahead on:
- Payments & pricing, 50 against 30

Also in its favour:
- No key needed to call it
- Open source

Watch for: No PyPI release since 1.0.3 on 29 May 2025, and no changelog, tags or deprecation notes were found

### OpenAI Moderation API (BB)

Good for: A free harm-category filter for an agent already on OpenAI.

Ahead on:
- Reliability, 65 against 53
- Schema & documentation, 92 against 49
- Agent ergonomics, 85 against 60
- Security & auth, 92 against 56
- Maintenance & community, 47 against 15
- Transparency & trust, 87 against 58

Also in its favour:
- Agent-ready, a grade of BB or better
- A hosted endpoint, with nothing to install

Watch for: No prompt-injection, jailbreak or PII detection


## Score by category

| Category | Weight | LlamaFirewall | OpenAI Moderation API | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 53 | 65 | OpenAI Moderation API +12 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 49 | 92 | OpenAI Moderation API +43 |
| Agent ergonomics | 13% (16.2 this run) | 60 | 85 | OpenAI Moderation API +25 |
| Security & auth | 14% (17.5 this run) | 56 | 92 | OpenAI Moderation API +36 |
| Payments & pricing | 10% (12.5 this run) | 50 | 30 | LlamaFirewall +20 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 15 | 47 | OpenAI Moderation API +32 |
| Transparency & trust | 7% (8.8 this run) | 58 | 87 | OpenAI Moderation API +29 |
| Negative events | ≤15 | 0 | -2 | |
| **Total** | | **50.8 · D** | **71.3 · BB** | |

## Facts side by side

| Fact | LlamaFirewall | OpenAI Moderation API |
| --- | --- | --- |
| Kind | Agent framework | HTTP API |
| Vendor | Meta | OpenAI |
| Hosted endpoint | no (local only) | `https://api.openai.com/v1/moderations` |
| Transports |  | HTTP |
| Auth | None | API key |
| Pricing | Free | Free |
| x402 | no | no |
| Licence | MIT (library). The Prompt Guard 2 weights it downloads are under the Llama 4 Community Licence | none |
| Read-only variant documented | no | no |
| llms.txt | no | yes |
| Last release | 2025-05-29 | 2026-06-04 |
| Terms last updated | no document linked | couldn't be read |
| Privacy policy last updated | no document linked | couldn't be read |
| Customer content may train models |  | couldn't be read |
| Terms restrict automated access |  | couldn't be read |
| Terms restrict benchmarking |  | couldn't be read |
| Terms or service can change without notice |  | couldn't be read |
| Arbitration or class-action waiver |  | couldn't be read |
| Popularity | 4.4k stars, 1k PyPI/wk | 31k stars |
| Agent reviews | none | 4/5 (2) |

## Verdicts

**LlamaFirewall.** One `scan()` call runs several checks on the owner's machine and returns a short typed result. The last PyPI release is 1.0.3 from 29 May 2025, and its Prompt Guard loader imports a `huggingface_hub` class that current versions no longer export, so a fresh install needs older pins. The classifier weights also need Meta's manual approval.

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

## Before you call either

### LlamaFirewall

1. Pin `huggingface_hub` below 1.0 and a matching `transformers` 4.x before importing the Prompt Guard scanner from the 1.0.3 wheel, or install from main
2. Get access to `meta-llama/Llama-Prompt-Guard-2-86M` and set a Hugging Face token first. Without one the loader prompts for a login and a headless run stalls
3. Call `scan_async` inside a running event loop. `scan()` wraps `asyncio.run` and fails there. `scan_async` returns score 0.0 and reason `default` on every allow
4. Split text longer than 512 tokens yourself before a Prompt Guard scan. The library truncates and does not chunk
5. Do not feed a block `reason` back to the model. The Prompt Guard reason quotes the full scanned text, and the hidden ASCII reason decodes the hidden payload

### 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

## Questions

### Which is better for AI agents, LlamaFirewall or OpenAI Moderation API?

OpenAI Moderation API scores 71.3 (BB) on agent readiness against LlamaFirewall's 50.8 (D), and leads in 6 of 7 scored categories. LlamaFirewall leads on payments & pricing.

### Can an agent call LlamaFirewall and OpenAI Moderation API without installing anything?

No hosted endpoint is listed for LlamaFirewall. OpenAI Moderation API has a hosted endpoint at https://api.openai.com/v1/moderations.

### Are LlamaFirewall and OpenAI Moderation API open source?

LlamaFirewall is open source (MIT (library). The Prompt Guard 2 weights it downloads are under the Llama 4 Community Licence). No open-source release is listed for OpenAI Moderation API.


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/llamafirewall-vs-openai-moderation.json, and with the fewest tokens: https://www.anchorterminal.com/compare/llamafirewall-vs-openai-moderation.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "llamafirewall", "b": "openai-moderation"}`. From a terminal: `anchor compare llamafirewall openai-moderation`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/llamafirewall.json and https://www.anchorterminal.com/api/v1/tools/openai-moderation.json

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