# x402-zadenworks URL Change Watcher

> x402-zadenworks URL Change Watcher is a paid API for AI agents from x402-zadenworks.zaden-gaming.workers.dev, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-28).

Checks whether a URL's content has changed since the last check, reporting true/false/null (first check) plus added/removed paragraphs when changed.

## Facts

- Endpoint: POST https://x402-zadenworks.zaden-gaming.workers.dev/watch?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-28
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-zadenworks-url-change-watcher-64842e45
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_4ZhPNTnqDZVsBhVQH8d8v

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-zadenworks-url-change-watcher-64842e45 -d '<json body>'
```

Example prompt: Can you check if the content at https://example.com/blog/latest-news has changed since the last time we looked at it, and if so show me what paragraphs were added or removed?

## When to prefer this

Choose this endpoint when you need lightweight, per-call change detection on a specific URL without setting up a dedicated monitoring service. It is ideal for agents that periodically poll a page and need to know both whether content changed and exactly which paragraphs were added or removed — not just a binary changed signal. Prefer it over full-page scraping endpoints when you already have a prior baseline and only need the diff. It is not a persistent subscription service; the caller is responsible for scheduling repeat checks.

## Known failure modes

- URL is unreachable or returns a non-200 status — endpoint may return an error or null changed value
- First-time check always returns null for changed since no prior snapshot exists
- Dynamic or JavaScript-heavy pages may produce false positives if client-side content varies each render
- Rate limit or payment failure ($0.01 USDC per call) causes request rejection
- Invalid or malformed URL input results in an error response

## How this service works

Fourteen pay-per-call web tools for AI agents, billed in USDC on Base with no account or API key. START WITH /audit -- one call returns a complete page health check (SEO + structured data + accessibility, optionally plus links and sitemap) with a single score and one worst-first findings list. The parts are also sold individually. SITE AUDIT: /seo (on-page SEO and meta tags), /links (broken links), /sitemap (robots.txt and XML sitemap crawlability), /structured (JSON-LD and social preview tags), /a11y (WCAG accessibility) -- each scored 0-100 with a prioritised issue list. READING: /read (clean markdown), /snap (screenshot, PDF or rendered HTML), /tables (every HTML table as structured JSON), /verify (does a claim actually appear on this page). MONITORING: /watch (has this page changed), /compare (what differs between two pages). Plus /rank (best x402 service for a task) and /batch (several operations behind one payment).

## Output

Returns a 'changed' field that is true (content differs from last check), false (content unchanged), or null (first time this URL has been checked — no baseline yet). When changed is true, also returns arrays of added and removed paragraph strings showing exactly what text was added or removed between checks.

## 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",
    "bodyType",
    "body"
   ],
   "properties": {
    "body": {
     "type": "object",
     "required": [
      "url"
     ],
     "properties": {
      "key": {
       "type": "string",
       "description": "Optional private baseline namespace"
      },
      "url": {
       "type": "string",
       "description": "Public http/https URL to watch"
      },
      "waitMs": {
       "type": "integer",
       "maximum": 5000,
       "minimum": 0
      },
      "selector": {
       "type": "string",
       "description": "Optional CSS selector to scope the watched content to"
      }
     }
    },
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "POST"
     ],
     "type": "string"
    },
    "bodyType": {
     "enum": [
      "json",
      "form-data",
      "text"
     ],
     "type": "string"
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "url": {
       "type": "string"
      },
      "changed": {
       "type": [
        "boolean",
        "null"
       ]
      },
      "finalUrl": {
       "type": "string"
      },
      "checkedAt": {
       "type": "string"
      },
      "addedParagraphs": {
       "type": "array",
       "items": {
        "type": "string"
       }
      },
      "removedParagraphs": {
       "type": "array",
       "items": {
        "type": "string"
       }
      }
     }
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "url": "https://example.com",
  "status": 200,
  "changed": null,
  "finalUrl": "https://example.com/",
  "checkedAt": "2026-08-07T00:00:00.000Z",
  "wordCount": 28,
  "addedParagraphs": [],
  "removedParagraphs": []
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-zadenworks-url-change-watcher-64842e45/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402-zadenworks.zaden-gaming.workers.dev](https://www.zero.xyz/host/x402-zadenworks.zaden-gaming.workers.dev/llms.txt)