# x402 Metadata Drift Detector

> x402 Metadata Drift Detector is a paid API for AI agents from api.zfinia.com, paid per call via x402, $0.006/call, status unknown (last checked 2026-11-01).

Compares a live x402 payment challenge against a saved baseline to surface price changes, offer additions/removals, protocol version changes, and payee address changes — without making any payment.

## Facts

- Endpoint: POST https://api.zfinia.com/x402/v1/x402-metadata-drift?utm_source=zero.xyz
- Price: $0.006/call
- Payment: x402
- Status: unknown
- Last checked: 2026-11-01
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-metadata-drift-detector-d9a62f38
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_-HkyZwhtCnY7yAwf8fs_y

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 x402-metadata-drift-detector-d9a62f38 -d '<json body>'
```

Example prompt: Check if the payment terms for https://api.example.com/premium-data have changed since last week — here's the baseline challenge I saved from the previous preflight — tell me if the price, offers, protocol version, or payee address are any different now.

## When to prefer this

Use this endpoint when you already have a previously captured x402 challenge object and want to detect whether the endpoint's payment terms have drifted — specifically price changes, offer inventory changes, protocol version bumps, or payee address substitutions. Prefer this over x402 Endpoint Preflight when you need a structured diff rather than just the current challenge state, and when detecting unauthorized or silent changes is the primary goal. Ideal for monitoring pipelines, compliance audits, or before re-authorizing payment to a vendor API.

## Known failure modes

- URL uses disallowed credentials, non-standard port, or fragment — request refused
- Target endpoint is not currently serving an x402 challenge — no diff can be computed
- Baseline object is malformed or missing required fields — comparison fails
- Target origin is not on the reviewed allowlist — request refused
- Target endpoint is unreachable or times out — probe failure returned

## How this service works

Did this paid endpoint change its terms since you last looked? Give it a previous challenge as the baseline and it returns every difference: price changes with old and new amounts, offers added or removed, a protocol version change, and a payee_changed flag when a new recipient address appears. Never pays the endpoint.

## Output

A structured diff object showing: each price change with the old and new amounts, a list of offers added since the baseline, a list of offers removed since the baseline, whether the protocol version changed, and a boolean payee_changed flag indicating if the recipient wallet address has changed. No payment is made during this operation.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "url": {
   "type": "string",
   "maxLength": 2048
  },
  "body": {
   "type": "object"
  },
  "method": {
   "enum": [
    "GET",
    "POST"
   ],
   "type": "string"
  },
  "baseline": {
   "type": "object"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-metadata-drift-detector-d9a62f38/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.zfinia.com](https://www.zero.xyz/host/api.zfinia.com/llms.txt)