> ## Documentation Index
> Fetch the complete documentation index at: https://docs.perplexity.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Safety Identifiers

> Identify your end users so a policy violation blocks one user instead of your whole API organization.

## Overview

If your application serves many end users through one API organization, send the `Perplexity-Safety-Identifier` header with each request. Use a stable ID that your application assigns to the end user who triggered the request.

Without this header, Perplexity and its model providers can attribute a request only to your API organization. If one of your end users violates the [Perplexity API Terms of Service](https://www.perplexity.ai/hub/legal/perplexity-api-terms-of-service) or a [model provider's terms](https://www.perplexity.ai/hub/legal/third-party-models), we may have to restrict your whole organization. With the header, we can block just that end user, and the rest of your traffic continues to work.

## Send the header

* Use an opaque ID, such as your internal user ID. Never send personal information.
* 1 to 64 printable ASCII characters, with no spaces or commas. Invalid values are ignored.

```bash cURL theme={null}
curl https://api.perplexity.ai/router/v1/responses \
  -H "Authorization: Bearer $PERPLEXITY_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Perplexity-Safety-Identifier: user_8f14e45f" \
  -d '{"model": "perplexity/kimi-k3", "input": "Reply with OK."}'
```

With the OpenAI or Anthropic SDKs, pass the header with `extra_headers` (Python) or the `headers` request option (TypeScript).

## Blocked users

Requests with a blocked identifier return HTTP 403:

```json theme={null}
{
  "error": {
    "message": "This safety identifier is blocked for your API organization.",
    "type": "safety_identifier_blocked",
    "code": 403
  }
}
```