Moderations API

POST /api/v1/moderations — classify text for harmful content. OpenAI-compatible, served by guard models.

Check whether text is harmful before you send it to a model or show it to a user. The request and response follow OpenAI's POST /v1/moderations, so the OpenAI SDKs work by changing the base URL and key. Guard models such as NVIDIA Nemotron Content Safety and Llama Guard do the classification.

Authenticate with an LLM API key (sk-ar-v1-…) from /dashboard/keys, sent as Authorization: Bearer ….

Request

Field	Type	Required	Description
`input`	string \| string[] \| `{type:"text", text}`[]	yes	Up to 32 texts, each up to 32,000 characters. Images are not supported.
`model`	string	no	A moderation model id. Defaults to `nvidia/nemotron-3.5-content-safety`. OpenAI ids such as `omni-moderation-latest` use the default too.
`session_id`	string	no	Groups related requests in Request Logs.

curl https://anyrouter.dev/api/v1/moderations \
  -H "Authorization: Bearer $ANYROUTER_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"input": ["What is a good pasta recipe?", "How do I buy a gun with no background check?"]}'

Response

{
  "id": "modr-req_01HXYZ",
  "model": "nvidia/nemotron-3.5-content-safety",
  "results": [
    {
      "flagged": false,
      "categories": { "harassment": false, "illicit/violent": false, "violence": false },
      "category_scores": { "harassment": 0, "illicit/violent": 0, "violence": 0 },
      "guard_categories": []
    },
    {
      "flagged": true,
      "categories": { "harassment": false, "illicit/violent": true, "violence": false },
      "category_scores": { "harassment": 0, "illicit/violent": 1, "violence": 0 },
      "guard_categories": ["guns_and_illegal_weapons"]
    }
  ],
  "usage": { "prompt_tokens": 955, "completion_tokens": 24, "total_tokens": 979, "cost": 0 }
}

The example is shortened. Every result lists all 13 OpenAI categories: harassment, harassment/threatening, hate, hate/threatening, illicit, illicit/violent, self-harm, self-harm/intent, self-harm/instructions, sexual, sexual/minors, violence, violence/graphic.

Field	Description
`results[]`	One result per input, in input order.
`flagged`	`true` when the guard model judged the text unsafe.
`categories`	OpenAI categories the guard's verdict maps to.
`category_scores`	`1` for a flagged category, else `0`. Guard models return a verdict, not a probability.
`guard_categories`	The guard model's own labels. Some (privacy, defamation, elections, …) have no OpenAI category: the text is still `flagged`, but no OpenAI category is set.
`usage`	Tokens summed over every input. Priced at the model's per-1M token rates.

Models

Moderation models appear under the Moderation tab at anyrouter.dev/models:

Model	Notes
`nvidia/nemotron-3.5-content-safety`	Default. Returns categories.
`meta/llama-guard-4-12b`	MLCommons hazard codes S1–S14. Requires your own DeepInfra or OpenRouter key (BYOK).
`openai/gpt-oss-safeguard-20b`	Policy-following reasoning classifier. Requires your own key (Groq, OpenRouter, Vercel, Hugging Face, or Nous).

Errors

Status	Code	When
400	`invalid_request`	`input` is missing, empty, contains an image, or exceeds the limits.
400	`model_not_moderation_compatible`	The model is not a moderation model.
502	`upstream_invalid_response`	The guard model replied without a verdict.
502	`upstream_error`	Every provider for the model failed.