# x402 Money Farm: Page Fingerprint / Change Detection

> x402 Money Farm: Page Fingerprint / Change Detection is a paid API for AI agents from x402-money-farm.fly.dev, paid per call via x402, $0.015/call, status unknown (last checked 2026-10-03).

Generates a noise-normalised structural fingerprint of a web page and compares it against a previous digest to detect whether the page content has meaningfully changed.

## Facts

- Endpoint: GET https://x402-money-farm.fly.dev/v1/fingerprint?utm_source=zero.xyz
- Price: $0.015/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-03
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-money-farm-page-fingerprint-change-detection-31d3dd45
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_4bJcX8bNVdhspcGlGdn5z

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-money-farm-page-fingerprint-change-detection-31d3dd45
```

Example prompt: Check whether https://example.com/pricing has changed since my last visit — compare it against my previous digest 'abc123xyz' and let me know if there's been any meaningful update, scoping to the main .content div.

## When to prefer this

Choose this endpoint when you need to detect whether a specific web page has meaningfully changed over time, especially when you want noise-normalised comparison (ignoring timestamps, counters, etc.) rather than a raw byte diff. Ideal for monitoring competitor pages, content update alerts, or caching decisions. Prefer over generic HTTP fetchers when a structured change verdict and persistent digest history per payer are needed. Use the CSS selector option to scope monitoring to a specific page section.

## Known failure modes

- Target URL is unreachable or returns non-200 status — error or empty response
- Invalid or malformed URL in query params — validation error
- CSS selector matches nothing on the page — fingerprint may be empty or fall back to full page
- Previous digest is malformed or unrecognised format — comparison skipped or error returned
- Payment not completed — 402 response with payment requirements
- Rate limits or timeouts on the remote page — delayed or failed fetch

## How this service works

Page Fingerprint / Change Detection — Stable content + structure fingerprint of a page, noise-normalised, with a change verdict against a caller-supplied previous digest or the last digest this payer saw.

## Output

Returns a stable content-and-structure fingerprint (digest) of the requested page, normalised to filter out noise such as timestamps or counters. Includes a boolean change verdict comparing the current fingerprint to either the caller-supplied previous digest or the last digest recorded for this payer, plus a similarity score used against the configured threshold.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "url"
     ],
     "properties": {
      "url": {
       "type": "string",
       "format": "uri",
       "description": "Absolute http(s) URL of the page to process."
      },
      "fresh": {
       "type": "boolean",
       "default": false
      },
      "previous": {
       "type": "string",
       "description": "Previous digest to compare against."
      },
      "remember": {
       "type": "boolean",
       "default": true
      },
      "selector": {
       "type": "string",
       "description": "CSS selector to scope the fingerprint."
      },
      "ignore_numbers": {
       "type": "boolean",
       "default": false
      },
      "similarity_threshold": {
       "type": "integer",
       "default": 3,
       "maximum": 32,
       "minimum": 0
      }
     },
     "additionalProperties": false
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-money-farm-page-fingerprint-change-detection-31d3dd45/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402-money-farm.fly.dev](https://www.zero.xyz/host/x402-money-farm.fly.dev/llms.txt)