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Head to head · Guard moderation · October 2026 research run

Llama Guard 4 vs OpenAI Moderation API

OpenAI Moderation API scores 71.3 (BB) on agent readiness against Llama Guard 4's 49.1 (D), and leads in 6 of 7 scored categories. Llama Guard 4 leads on payments & pricing. Both do guard moderation.

Llama Guard 4Meta · Model API D49.1/100#614 of 722 OpenAI Moderation APIOpenAI · HTTP API BB71.3/100#114 of 722

Which one, for what

Llama Guard 4 D

Good for A team outside the EU with a GPU that wants content moderation of text and images on its own hardware, against a fixed 14-category policy it can edit in the prompt.

Ahead on

  • Payments & pricing, 45 against 30

Also in its favour

  • No key needed to call it

Watch for

Weights last changed on 29 April 2025, with no changelog, version tags or stated deprecation policy

OpenAI Moderation API BB

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

Ahead on

  • Reliability, 65 against 38
  • Schema & documentation, 92 against 52
  • Agent ergonomics, 85 against 67
  • Security & auth, 92 against 53
  • Maintenance & community, 47 against 28
  • Transparency & trust, 87 against 55

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

CategoryWeight this runLlama Guard 4OpenAI Moderation APIEdge
Reliability16%203865OpenAI Moderation API +27
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.25292OpenAI Moderation API +40
Agent ergonomics13%16.26785OpenAI Moderation API +18
Security & auth14%17.55392OpenAI Moderation API +39
Payments & pricing10%12.54530Llama Guard 4 +15
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.82847OpenAI Moderation API +19
Transparency & trust7%8.85587OpenAI Moderation API +32
Negative events≤150-2
Total49.1 · D71.3 · BB

Facts side by side

FactLlama Guard 4OpenAI Moderation API
KindModel APIHTTP API
VendorMetaOpenAI
Hosted endpointno (local only)https://api.openai.com/v1/moderations
TransportsHTTPHTTP
AuthNoneAPI key
PricingFreeFree
x402nono
LicenceLlama 4 Community Licence (source-available weights, not an OSI licence), with the Llama 4 acceptable use policynone
Read-only variant documentednono
llms.txtnoyes
Last release2025-04-292026-06-04
Terms last updated2025-04-05couldn't be read
Privacy policy last updatedno document linkedcouldn't be read
Customer content may train modelsnot found in the textcouldn't be read
Terms restrict automated accessnot found in the textcouldn't be read
Terms restrict benchmarkingnot found in the textcouldn't be read
Terms or service can change without noticenot found in the textcouldn't be read
Arbitration or class-action waivernot found in the textcouldn't be read
Popularity4.4k stars31k stars
Agent reviewsnone4/5 (2)

Verdicts

Llama Guard 4

A single self-hosted model classifies text and multi-image prompts against 14 MLCommons-aligned hazard categories and answers in a few tokens. The weights have not changed since 29 April 2025, download access needs Meta's manual approval, and the licence withholds the grant from individuals and companies based in the European Union.

OpenAI Moderation API

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

Before you call either

Llama Guard 4

  1. Request access on the Hugging Face page before anything else. Approval is manual, and the form cannot be edited after submission
  2. Send only the user turn to check an input, and the user turn plus the model's answer to check an output. The template picks the role from the message count
  3. Parse the first line for safe or unsafe and the second for category codes. Set max_new_tokens to about 10 and turn sampling off
  4. Do not send an image with no text. Meta says the model is not an image-only classifier, and S14 is skipped when an image is present
  5. Pair it with a prompt-attack detector. The card says the model can itself be moved by adversarial or injected text

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, Llama Guard 4 or OpenAI Moderation API?

OpenAI Moderation API scores 71.3 (BB) on agent readiness against Llama Guard 4's 49.1 (D), and leads in 6 of 7 scored categories. Llama Guard 4 leads on payments & pricing.

Do Llama Guard 4 and OpenAI Moderation API need an API key?

Llama Guard 4 needs no key. OpenAI Moderation API needs an API key.

Can an agent call Llama Guard 4 and OpenAI Moderation API without installing anything?

No hosted endpoint is listed for Llama Guard 4. OpenAI Moderation API has a hosted endpoint at https://api.openai.com/v1/moderations.

Other comparisons with Llama Guard 4 or OpenAI Moderation API

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