# Delx Commerce — Referrer Policy Check

> Delx Commerce — Referrer Policy Check is a paid API for AI agents from commerce.delx.ai, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-01).

Validates whether an HTTP Referrer-Policy header value is accepted against a list of allowed policy values

## Facts

- Endpoint: POST https://commerce.delx.ai/api/v1/x402/referrer-policy-check?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-01
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/delx-commerce-referrer-policy-check-878a7d14
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_YK9dXZOvCIjGMy2di_prq

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability delx-commerce-referrer-policy-check-878a7d14 -d '<json body>'
```

Example prompt: Check if the referrer policy value 'strict-origin-when-cross-origin' is accepted — the allowed values are 'no-referrer', 'same-origin', and 'strict-origin-when-cross-origin'.

## When to prefer this

Choose this endpoint when you need a lightweight, pay-per-call, no-signup validation of HTTP Referrer-Policy header values against a custom allowed list — especially in agent pipelines requiring verifiable, in-memory-only processing with no data retention. Prefer it over building custom logic when auditability (input SHA-256, zero external calls) matters for compliance or CI checks.

## Known failure modes

- Invalid or missing 'value' field returns an error
- Allowed list exceeds 256 items or individual strings exceed 8192 characters may be rejected
- Malformed JSON body returns a parse error
- Non-string values in the allowed array may cause schema validation failures

## How this service works

Pay-per-result APIs for agents. No signup. Exact price. Verifiable delivery. USDC on Base + Solana via x402.

## Output

Returns a JSON object indicating whether the provided referrer-policy value is accepted, including the matched value, a pass/fail status, the operation name, and evidence metadata such as whether input was retained, its SHA-256 hash, and the number of external calls made (always 0 — fully in-memory).

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "value": {
   "type": "string",
   "maxLength": 8192,
   "description": "Value supplied to Referrer Policy Check; used only for this bounded calculation and processed in memory without retention."
  },
  "allowed": {
   "type": "array",
   "items": {
    "type": "string",
    "maxLength": 8192
   },
   "maxItems": 256,
   "description": "Allowed supplied to Referrer Policy Check; used only for this bounded calculation and processed in memory without retention."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "result": {
   "value": "strict-origin-when-cross-origin",
   "accepted": true
  },
  "schema": "delx/util-referrer-policy-check/v1",
  "status": "pass",
  "evidence": {
   "retained": false,
   "input_sha256": "d9c8b9b264fe994897afb78430721e7bed86899de05bf6d219f03a39c301eaa1",
   "external_calls": 0
  },
  "operation": "web_reliability:referrer_policy_check"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/delx-commerce-referrer-policy-check-878a7d14/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from commerce.delx.ai](https://www.zero.xyz/host/commerce.delx.ai/llms.txt)